Tizanidine

Generic name: tizanidine hydrochloride · Brand names: Zanaflex (capsules and tablets), Ontralfy (oral solution, not covered)

Quick facts

Drug class
The label calls it a central alpha-2-adrenergic agonist. MedlinePlus calls it a skeletal muscle relaxant. openFDA pharmacologic class (EPC) could not be retrieved.
Source
DailyMed Rising label Highlights; MedlinePlus
Source text (exact source wording)
Tizanidine tablets are a central alpha-2-adrenergic agonist indicated for the treatment of spasticity. (Highlights, Indications and Usage) || MedlinePlus: Tizanidine is in a class of medications called skeletal muscle relaxants.
Rx or otc
Rx (package label: Rx only)
Controlled schedule
Not a controlled substance (label 9.1)
Forms and strengths
  • Tablets USP 2 mg: white to off-white, round, uncoated, debossed 39, functionally scored (Rising). Source: Section 3
  • Tablets USP 4 mg: white to off-white, round, uncoated, debossed 40, functionally scored (Rising). Source: Section 3
  • Other forms exist (capsules, oral solution) and are not covered in this record
Generic available
Value
Yes; many ANDA tablet labels on DailyMed
Source
https://dailymed.nlm.nih.gov/dailymed/services/v2/spls.json?drug_name=tizanidine
Common use one line
Central alpha-2 agonist used to treat spasticity in adults (Section 1).

What it is used for

Tizanidine tablets are used to treat spasticity in adults.
Section
1 INDICATIONS AND USAGE
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine tablets are indicated for the treatment of spasticity in adults.

How it works

Tizanidine is a central alpha-2 agonist that presumably reduces spasticity by increasing presynaptic inhibition of motor neurons, with the greatest effects on polysynaptic pathways.
Section
12.1 Mechanism of Action
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine is a central alpha-2-adrenergic receptor agonist and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. The effects of tizanidine are greatest on polysynaptic pathways. The overall effect of these actions is thought to reduce facilitation of spinal motor neurons.

Dosage: adults

The recommended starting dose is 2 mg by mouth every 6 to 8 hours as needed, up to three doses in 24 hours. Dosage can be increased every 1 to 4 days by 2 mg to 4 mg per dose. The maximum total daily dosage is 36 mg, and single doses greater than 16 mg have not been studied. Tablets may be taken with or without food but consistently. Aminotransferase levels should be checked at baseline and 1 month after the maximum dose. When stopping, decrease the dosage by 2 mg to 4 mg per day.
Section
2.1; 2.2; 2.5; 2.6
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
2.1 Recommended Evaluation and Testing Before and After Initiating Tizanidine Tablets: Monitoring of aminotransferase levels is recommended at baseline and 1 month after maximum dose is achieved [see Warnings and Precautions (5.2)]. || 2.2 Recommended Dosage: The recommended starting dose is 2 mg by mouth every 6 to 8 hours, as needed, to a maximum of three doses in 24 hours. Dosage can be gradually increased every 1 to 4 days by 2 mg to 4 mg at each dose based on clinical response and tolerability. The maximum total daily dosage is 36 mg. Single doses greater than 16 mg have not been studied. There are pharmacokinetic differences when administering tizanidine between the fed or fasted state [see Clinical Pharmacology (12.3)]. Tizanidine tablets may be taken with or without food; however, consistent administration with respect to food is recommended to reduce variability in tizanidine plasma exposure. Because of the short duration of therapeutic effect, treatment with tizanidine tablets should be reserved for those daily activities and times when relief of spasticity is most important. || 2.5 Discontinuation of Tizanidine Tablets: When discontinuing tizanidine tablets, particularly in patients who have been receiving high doses for long periods or who may be on concomitant treatment with narcotics, decrease the dosage by 2 mg to 4 mg per day to minimize the risk of withdrawal adverse reactions [see Drug Abuse and Dependence (9.3)]. || 2.6 Switching Between With/Without Food and Different Tizanidine Dosage Forms: There are pharmacokinetic differences when: 1) switching between administration of tizanidine tablets with or without food 2) switching between dosage forms if being administered with food. If these situations occur, monitor patients for therapeutic effect or adverse reactions [see Dosage and Administration (2.2) and Clinical Pharmacology (12.3)].

Dosage: children

Safety and effectiveness in pediatric patients have not been established.
Section
8.4 Pediatric Use
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
8.4 Pediatric Use: Safety and effectiveness in pediatric patients have not been established.

Dosage adjustments

Drug interaction caps
The label gives no fixed dose caps. It says to avoid moderate or weak CYP1A2 inhibitors, and if needed together and side effects occur, to reduce or stop tizanidine.
Section
7.2
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Kidney
With creatinine clearance below 25 mL/min, use lower individual doses during titration, and if higher doses are needed increase the individual doses rather than the frequency.
Section
2.3; 8.6
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
2.3 Recommended Dosage in Patients with Renal Impairment: In patients with creatinine clearance < 25 mL/min, use lower individual doses during titration. If higher doses are required, the individual doses rather than dosing frequency should be increased [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)]. || 8.6 Renal Impairment: In patients with renal insufficiency (creatinine clearance < 25 mL/min), clearance of tizanidine was reduced [see Clinical Pharmacology (12.3)]. In these patients, dosage reduction is recommended [see Dosage and Administration (2.3)]. Because the risk of adverse reactions to tizanidine may be greater in patients with impaired renal function, monitor these patients closely for the onset or increase in severity of common adverse reactions [see Adverse Reactions (6.1)].
Liver
With liver impairment, use lower individual doses during titration. Dosage reduction is recommended and tizanidine should be used with caution.
Section
2.4; 8.7
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
2.4 Recommended Dosage in Patients with Hepatic Impairment: In patients with hepatic impairment, use lower individual doses during titration. If higher doses are required, individual doses rather than dosing frequency should be increased [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3)]. || 8.7 Hepatic Impairment: Tizanidine should be used with caution in patients with hepatic impairment. The influence of hepatic impairment on the pharmacokinetics of tizanidine has not been evaluated. Because tizanidine is extensively metabolized in the liver, hepatic impairment would be expected to have significant effects on pharmacokinetics of tizanidine [see Warnings and Precautions (5.2) and Clinical Pharmacology (12.3)]. In patients with hepatic impairment, dosage reduction is recommended [see Dosage and Administration (2.4)].
Elderly
Elderly patients may clear tizanidine more slowly, especially with kidney impairment, so care is taken in dose selection and renal function monitoring may be useful. Individual doses should be reduced during titration.
Section
8.5 Geriatric Use
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
8.5 Geriatric Use: Tizanidine is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function. Clinical studies of tizanidine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently than younger subjects. Pharmacokinetic data showed that younger subjects cleared tizanidine faster than the elderly subjects [see Clinical Pharmacology (12.3)]. In elderly patients with renal insufficiency (creatinine clearance < 25 mL/min), tizanidine clearance is reduced compared to healthy elderly subjects; this would be expected to lead to a longer duration of clinical effect. During titration, the individual doses should be reduced. If higher doses are required, individual doses rather than dosing frequency should be increased. Monitor elderly patients because they may have an increased risk for adverse reactions associated with tizanidine.

Missed dose

Medlineplus
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip it. Do not double up.
Section
MedlinePlus: What should I do if I forget a dose?
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
If your doctor has told you to take tizanidine regularly, take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Overdose

Label
Overdose cases included fatalities, often with multiple drugs. Signs include lethargy, somnolence, confusion, coma, slow heartbeat, low blood pressure and respiratory depression. Dialysis is not likely to be efficient. Symptoms generally resolve within one to three days. Management is similar to clonidine overdose.
Section
10 OVERDOSAGE
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
A review of the safety surveillance database revealed cases of intentional and accidental tizanidine overdose. Some of the cases resulted in fatality and many of the intentional overdoses were with multiple drugs, including CNS depressants. The clinical manifestations of tizanidine overdose were consistent with its known pharmacology. In the majority of cases, a decrease in sensorium was observed including lethargy, somnolence, confusion, and coma. Depressed cardiac function is also observed including most often bradycardia and hypotension. Respiratory depression is another common feature of tizanidine overdose. Should overdose occur, ensure the adequacy of an airway and monitor cardiovascular and respiratory function. Dialysis is not likely to be an efficient method of removing tizanidine from the body [see Description (11)]. In general, symptoms resolve within one to three days following discontinuation of tizanidine and administration of appropriate therapy. Because of the similar mechanism of action, symptoms and management of tizanidine overdose are similar to that following clonidine overdose. For the most recent information concerning the management of overdose, contact a poison control center.
Medlineplus
For overdose call poison control at 1-800-222-1222. Call 911 if the person has collapsed, had a seizure, has trouble breathing or can't be awakened.
Section
MedlinePlus: In case of emergency/overdose
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911. Symptoms of overdose may include: drowsiness extreme tiredness confusion slow heartbeat fainting dizziness slow or shallow breathing loss of consciousness

Storage

Label
Store at 25°C (77°F), with short trips to 15° to 30°C (59° to 86°F) allowed, in containers with a child resistant closure.
Section
16.2 Storage and Handling (Rising; labeler-specific)
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Dispense in containers with child resistant closure.
Medlineplus
Keep it in the original container, tightly closed, out of reach of children, at room temperature away from heat and moisture.
Section
MedlinePlus: storage and disposal
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Boxed warning

NONE

Contraindications

Do not use with strong CYP1A2 inhibitors or if you have had hypersensitivity (including anaphylaxis and angioedema) to tizanidine or the tablet ingredients.
Section
4 CONTRAINDICATIONS
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine tablets are contraindicated in patients: taking strong CYP1A2 inhibitors [see Drug Interactions (7.1)]. with a history of hypersensitivity to tizanidine or the ingredients in tizanidine tablets. Symptoms have included anaphylaxis and angioedema [see Warnings and Precautions (5.5)].

Warnings and precautions

Tizanidine can lower blood pressure, and fainting has been reported after approval. Risk may be reduced by slow dose increases and monitoring. Extra monitoring is advised with blood pressure medicines, and use with other alpha-2 agonists is not recommended. Use with strong CYP1A2 inhibitors is contraindicated.
Heading
5.1 Hypotension
Section
5.1
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine is an α2-adrenergic agonist that can produce hypotension [see Adverse Reactions (6.1) and Drug Interactions (7.5)]. Syncope has been reported in patients treated with tizanidine in the postmarketing setting. The risk of hypotension may be minimized by dose titration; monitoring for signs and symptoms of hypotension prior to dosage increase may minimize the risks associated with hypotension. In addition, patients moving from a supine to fixed upright position may be at increased risk for hypotension and orthostatic effects. Monitor for hypotension when tizanidine is used in patients receiving concurrent antihypertensive therapy. It is not recommended that tizanidine be used with other α2-adrenergic agonists. Clinically significant hypotension (decreases in both systolic and diastolic pressure) has been reported with concomitant administration of tizanidine and strong CYP1A2 inhibitors [see Clinical Pharmacology (12.3)]. Therefore, concomitant use of tizanidine with strong CYP1A2 inhibitors is contraindicated [see Contraindications (4) and Drug Interactions (7.1)].
Tizanidine may injure the liver. Liver enzyme (aminotransferase) tests are recommended at baseline and 1 month after the maximum dose is reached, or if liver injury is suspected.
Heading
5.2 Liver Injury
Section
5.2
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine may cause hepatocellular liver injury. Liver function test abnormality and hepatotoxicity have been observed with tizanidine [see Adverse Reactions (6.1, 6.2)]. Monitoring of aminotransferase levels is recommended at baseline and 1 month after maximum dose is achieved, or if hepatic injury is suspected [see Dosage and Administration (2.1) and Use in Specific Populations (8.7)].
Tizanidine can cause sedation that interferes with everyday activity. Sedation peaked after the first week of dose increases and then stayed stable in studies. Effects add up with alcohol and other CNS depressants.
Heading
5.3 Sedation
Section
5.3
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine can cause sedation, which may interfere with everyday activity. In the multiple dose studies of tizanidine, the prevalence of patients with sedation peaked following the first week of titration and then remained stable for the duration of the maintenance phase of the study [see Adverse Reactions (6.1)]. The CNS depressant effects of tizanidine with alcohol and other CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants) may be additive [see Drug Interactions (7.4)]. Monitor patients who take tizanidine with another CNS depressant for symptoms of excess sedation.
Hallucinations or delusions were reported in 5 of 170 patients (3%) in two North American controlled studies, and also after approval. Discontinuing tizanidine should be considered if hallucinations develop.
Heading
5.4 Hallucinosis/Psychotic-Like Symptoms
Section
5.4
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine use has been associated with hallucinations. Formed, visual hallucinations or delusions were reported in 5 of 170 patients (3%) in two North American controlled clinical studies. Most of the patients were aware that the events were unreal. One patient developed psychosis in association with the hallucinations. One patient among these 5 continued to have problems for at least 2 weeks following discontinuation of tizanidine. Hallucinations have also been reported with tizanidine use in the postmarketing setting. Consider discontinuing tizanidine in patients who develop hallucinations.
Tizanidine can cause anaphylaxis, with breathing problems, hives, and swelling of the throat and tongue reported. It must not be used in anyone with a history of hypersensitivity to it.
Heading
5.5 Hypersensitivity Reactions
Section
5.5
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine can cause anaphylaxis. Signs and symptoms of hypersensitivity, including respiratory compromise, urticaria, and angioedema of the throat and tongue, have been reported. Tizanidine is contraindicated in patients with a history of hypersensitivity reactions to tizanidine [see Contraindications (4)].
Stopping tizanidine suddenly can cause rebound high blood pressure, fast heart rate and increased muscle tone, especially after high doses (20 to 28 mg daily) for 9 weeks or more or with narcotics. The dose should be decreased slowly.
Heading
5.6 Withdrawal Adverse Reactions
Section
5.6
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine can cause withdrawal adverse reactions, which include rebound hypertension, tachycardia, and hypertonia. To minimize the risk of these reactions, particularly in patients who have been receiving high doses of tizanidine (20 to 28 mg daily) for long periods of time (9 weeks or more) or who may be on concomitant treatment with narcotics, the tizanidine dosage should be decreased slowly [see Dosage and Administration (2.5)].

Pregnancy and breastfeeding

Label
There are no adequate data in pregnant women. Animal studies showed developmental toxicity at doses less than those used clinically. No data on human milk. Benefits of breastfeeding should be weighed against the mother's need for tizanidine.
Section
8.1; 8.2; 8.3
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
8.1 Pregnancy, Risk Summary: There are no adequate data on the developmental risk associated with use of tizanidine in pregnant women. In animal studies, administration of tizanidine during pregnancy resulted in developmental toxicity (embryofetal and postnatal offspring mortality and growth deficits) at doses less than those used clinically, which were not associated with maternal toxicity (see Animal Data). || 8.2 Lactation, Risk Summary: There are no data on the presence of tizanidine in human milk, the effects on the breastfed infant, or the effects on human milk production. Animal studies have reported the presence of tizanidine in the milk of lactating animals. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for tizanidine and any potential adverse effects on the breastfed infant from tizanidine or from the underlying maternal condition. || 8.3 Females and Males of Reproductive Potential: There are no adequate and well-controlled studies in humans on the effect of tizanidine on female or male reproductive potential. Oral administration of tizanidine to male and female rats resulted in adverse effects on fertility [see Nonclinical Toxicology (13.1)].
Medlineplus
Tell your doctor if you are pregnant, plan to be, or are breast-feeding. If you become pregnant while taking tizanidine, call your doctor.
Section
MedlinePlus: special precautions
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking tizanidine, call your doctor.

Side effects

Common
The most common side effects are dry mouth, somnolence, asthenia and dizziness, each in more than 10% of tizanidine-treated patients and more than with placebo.
Section
Highlights: Adverse Reactions
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Threshold
greater than 10% of patients taking tizanidine and greater than in patients taking placebo
Source text (exact source wording)
The most common adverse reactions (greater than 10% of patients taking tizanidine and greater than in patients taking placebo) were dry mouth, somnolence, asthenia, and dizziness (6.1)
Common medlineplus
MedlinePlus lists dizziness, drowsiness, unusual tiredness or weakness, nervousness, vomiting, dry mouth and constipation to report if severe or not going away.
Section
MedlinePlus: side effects
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
Tizanidine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: dizziness drowsiness unusual tiredness or weakness nervousness vomiting dry mouth constipation
Less common
In placebo-controlled studies, reactions in more than 2% and above placebo included urinary tract infection, infection, liver test abnormality, constipation, vomiting, speech disorder, blurred vision, urinary frequency, flu syndrome, dyskinesia, nervousness, pharyngitis and rhinitis, with percentages in the table above (for example dry mouth 49% vs 10% for placebo).
Section
6.1 Tables 1 and 2
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Table 1: Multiple Dose, Placebo-Controlled Studies. Adverse Reactions Reported in >2% of Patients Treated with Tizanidine Tablets and Incidence Greater than Placebo (Placebo N = 261 % / Tizanidine Tablet N = 264 %): Dry mouth 10 / 49; Somnolence 10 / 48; Asthenia* 16 / 41; Dizziness 4 / 16; UTI 7 / 10; Infection 5 / 6; Liver test abnormality 2 / 6; Constipation 1 / 4; Vomiting 0 / 3; Speech disorder 0 / 3; Amblyopia (blurred vision) <1 / 3; Urinary frequency 2 / 3; Flu syndrome 2 / 3; Dyskinesia 0 / 3; Nervousness <1 / 3; Pharyngitis 1 / 3; Rhinitis 2 / 3. *includes weakness, fatigue, and/or tiredness. || Table 2: Single Dose, Placebo-Controlled Study. Common Adverse Reactions Reported (Placebo N = 48 % / Tizanidine Tablet 8mg N = 45 % / Tizanidine Tablet 16 mg N = 49 %): Somnolence 31 / 78 / 92; Dry mouth 35 / 76 / 88; Asthenia* 40 / 67 / 78; Dizziness 4 / 22 / 45; Hypotension 0 / 16 / 33; Bradycardia 0 / 2 / 10.
Serious
Label postmarketing
After approval, reports included ventricular tachycardia, decreased blood pressure, hepatotoxicity, hepatitis, arthralgia, convulsion, paresthesia, tremor, muscle spasms, hallucinations, depression, Stevens Johnson Syndrome, anaphylactic reaction, exfoliative dermatitis and rash.
Section
6.2 Postmarketing Experience
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
6.2 Postmarketing Experience: The following adverse reactions have been identified during post approval use of tizanidine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Cardiac Disorders: Ventricular tachycardia, decreased blood pressure Hepatobiliary Disorders: Hepatotoxicity [see Warnings and Precautions (5.2)], hepatitis Musculoskeletal and Connective Tissue Disorders: arthralgia Nervous System Disorders: Convulsion, paresthesia, tremor, muscle spasms Psychiatric Disorders: Hallucinations [see Warnings and Precautions (5.4)], depression Skin and Subcutaneous Tissue Disorders: Stevens Johnson Syndrome, anaphylactic reaction [see Warnings and Precautions (5.5)], exfoliative dermatitis, rash
Label warnings
See warnings_and_precautions 5.1 to 5.6 (hypotension, liver injury, sedation, hallucinosis, hypersensitivity, withdrawal reactions).
Medlineplus
MedlinePlus lists symptoms that need a call to the doctor right away, including liver symptoms, allergic reaction signs, hallucinations, slow heartbeat and vision changes.
Section
MedlinePlus: side effects
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately: nausea, extreme tiredness, lack of energy, loss of appetite, unusual bleeding or bruising, pain in the upper right part of the stomach, yellowing of the skin or eyes, or flu-like symptoms rash; hives; itching; swelling of the face, throat, tongue, lips, or eyes; shortness of breath; or difficulty breathing or swallowing seeing things or hearing voices that do not exist slow heartbeat changes in vision

Interactions

Drugs
Do not use with fluvoxamine, ciprofloxacin or other strong CYP1A2 inhibitors. Blood pressure fell significantly and drowsiness and psychomotor impairment increased.
Name
Strong CYP1A2 inhibitors (fluvoxamine, ciprofloxacin)
Section
7.1
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Concomitant use of tizanidine with strong cytochrome P450 1A2 (CYP1A2) inhibitors (e.g., fluvoxamine, ciprofloxacin) is contraindicated. Changes in pharmacokinetics of tizanidine when administered with a strong CYP1A2 inhibitor resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications (4) and Clinical Pharmacology (12.3)].
Avoid these where possible. If needed together and low blood pressure, slow heartbeat or excessive drowsiness occur, the tizanidine dose is reduced or stopped.
Name
Moderate or weak CYP1A2 inhibitors (zileuton, amiodarone, mexiletine, propafenone, verapamil, cimetidine, famotidine, oral contraceptives, acyclovir, ticlopidine)
Section
7.2
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Concomitant use of tizanidine with moderate or weak CYP1A2 inhibitors (e.g., zileuton, antiarrhythmics [amiodarone, mexiletine, propafenone, and verapamil], cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided. If concomitant use is clinically necessary, and adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce tizanidine dosage or discontinue tizanidine therapy [see Clinical Pharmacology (12.3)].
Use together is not recommended. Women taking oral contraceptives had 50% lower clearance of tizanidine in a population analysis.
Name
Oral contraceptives
Section
7.3; 12.3
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Concomitant use of tizanidine with oral contraceptives is not recommended. However, if concomitant use is clinically necessary and adverse reactions such as hypotension, bradycardia, or excessive drowsiness occur, reduce or discontinue tizanidine therapy [see Clinical Pharmacology (12.3)]. || Retrospective analysis of population pharmacokinetic data following single and multiple dose administration of 4 mg tizanidine, however, showed that women concurrently taking oral contraceptives had 50% lower clearance of tizanidine compared to women not on oral contraceptives [see Drug Interactions (7.3))].
Alcohol raises tizanidine exposure and adverse reactions. Other CNS depressants add to sedation, so patients are monitored for excess sedation.
Name
Alcohol and other CNS depressants (benzodiazepines, opioids, tricyclic antidepressants)
Section
7.4
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Alcohol increases the exposure of tizanidine after administration of tizanidine. This was associated with an increase in adverse reactions of tizanidine. Concomitant use of tizanidine with CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may cause additive CNS depressant effects, including sedation. Monitor patients who take tizanidine with another CNS depressant for symptoms of excess sedation [see Clinical Pharmacology (12.3)].
Not recommended because blood pressure lowering effects may add up.
Name
Other alpha-2 adrenergic agonists
Section
7.5
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Concomitant use of tizanidine with other α2-adrenergic agonists is not recommended because hypotensive effects may be cumulative [see Warnings and Precautions (5.1)].
Blood pressure medicines may add to the blood pressure lowering effect, so low blood pressure is monitored.
Name
Antihypertensive medications
Section
7.6
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Concomitant use of tizanidine with antihypertensive medications may cause additive hypotensive effects [see Warnings and Precautions (5.1)]. Monitor patients who take tizanidine with antihypertensive medications for hypotension.
Tizanidine delayed the peak level of acetaminophen by 16 minutes. Acetaminophen did not change tizanidine levels.
Name
Acetaminophen
Section
12.3 Drug Interactions
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine delayed the Tmax of acetaminophen by 16 minutes. Acetaminophen did not affect the pharmacokinetics of tizanidine.
Food and alcohol
Tablets can be taken with or without food, but consistently the same way each time.
Name
Food (label)
Section
2.2
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Tizanidine tablets may be taken with or without food; however, consistent administration with respect to food is recommended to reduce variability in tizanidine plasma exposure.
Alcohol raises tizanidine exposure and side effects.
Name
Alcohol (label)
Section
7.4
Source
DailyMed Rising Pharma Holdings, Inc. tizanidine tablets label (set ID 433ac98f-ac22-44ad-a8b4-5db5560b9d0f), Revised: 8/2025
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Alcohol increases the exposure of tizanidine after administration of tizanidine. This was associated with an increase in adverse reactions of tizanidine.
MedlinePlus says alcohol can add to drowsiness and to continue your normal diet unless your doctor says otherwise.
Name
Alcohol and diet (MedlinePlus)
Section
MedlinePlus: special precautions; special dietary instructions
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
remember that alcohol can add to the drowsiness caused by this medication. Unless your doctor tells you otherwise, continue your normal diet.
Other
MedlinePlus names cimetidine and famotidine as over-the-counter products that may interact. The label also lists them.
Name
Cimetidine and famotidine (MedlinePlus)
Section
MedlinePlus: special precautions
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
the following nonprescription products may interact with tizanidine: cimetidine (Tagamet®); famotidine (Pepcid®, Pepcid® AC). Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking tizanidine. Do not start any of these medications while taking tizanidine without discussing with your healthcare provider.

Patient tips

Label section 17
Do not take with fluvoxamine or ciprofloxacin. Take exactly as prescribed, consistently with or without food, and do not switch between tablets and capsules. Do not exceed single doses of 8 mg or total daily doses of 36 mg. Do not stop suddenly. Rise slowly from lying or sitting. It may cause sedation, so be careful driving or using machinery, and alcohol adds to it. Use caution if you depend on spasticity for posture or balance.
Source
DailyMed Rising label, Section 17
Source url
https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
Source text (exact source wording)
Advise patients they should not take tizanidine if they are taking fluvoxamine or ciprofloxacin because of the increased risk of serious adverse reactions including severe lowering of blood pressure and sedation. Instruct patients to inform their healthcare providers when they start or stop taking any medication because of the risks associated with interaction between tizanidine and other medicines. || Tell patients to take tizanidine exactly as prescribed (consistently either with or without food) and not to switch between tablets and capsules. Inform patients that they should not take more tizanidine than prescribed because of the risk of adverse events at single doses greater than 8 mg or total daily doses greater than 36 mg. Tell patients that they should not suddenly discontinue tizanidine, because rebound hypertension and tachycardia may occur. || Warn patients that they may experience hypotension and to be careful when changing from a lying or sitting to a standing position. || Tell patients that tizanidine may cause them to become sedated or somnolent and they should be careful when performing activities that require alertness, such as driving a vehicle or operating machinery. Tell patients that the sedation may be additive when tizanidine is taken in conjunction with drugs (baclofen, benzodiazepines) or substances (e.g., alcohol) that act as CNS depressants. || Remind patients that if they depend on their spasticity to sustain posture and balance in locomotion, or whenever spasticity is utilized to obtain increased function, that tizanidine decreases spasticity and caution should be used.
Medlineplus how to take
Take consistently with or without food every 6 or 8 hours as needed, no more than three times a day. Do not switch between tablets and capsules without your doctor. Do not stop suddenly.
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
Take consistently either always with or always without food every 6 or 8 hours as needed, but no more than three times a day. Take exactly as directed. The capsules and tablets may release the medicine differently in the body. Do not switch from one product to the other without talking to your doctor. Do not stop taking tizanidine without talking to your doctor. If you suddenly stop taking tizanidine, your heart may beat faster and you may have increased blood pressure or tightness in your muscles. Your doctor will probably decrease your dose gradually.
Medlineplus avoid
Do not drive or use machinery until you know how it affects you. Alcohol adds to drowsiness. Get up slowly to avoid dizziness and fainting. Be careful if you rely on muscle tone for posture or balance.
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
you should know that this medication may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you. remember that alcohol can add to the drowsiness caused by this medication. you should know that tizanidine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking tizanidine. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up. tizanidine can decrease muscle tone, so be careful when walking or doing other activities where you rely on your muscle tone to help with your posture or balance.
Medlineplus when to call
Call your doctor right away for nausea, extreme tiredness, loss of appetite, unusual bleeding or bruising, upper right stomach pain, yellow skin or eyes, flu-like symptoms; rash, hives, itching or swelling of the face, throat, tongue, lips or eyes; trouble breathing or swallowing; seeing things or hearing voices that are not there; slow heartbeat; or vision changes.
Source
MedlinePlus Tizanidine (Last Revised - 10/15/2025)
Source url
https://medlineplus.gov/druginfo/meds/a601121.html
Source text (exact source wording)
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately: nausea, extreme tiredness, lack of energy, loss of appetite, unusual bleeding or bruising, pain in the upper right part of the stomach, yellowing of the skin or eyes, or flu-like symptoms rash; hives; itching; swelling of the face, throat, tongue, lips, or eyes; shortness of breath; or difficulty breathing or swallowing seeing things or hearing voices that do not exist slow heartbeat changes in vision

Alternatives

Class source
Label Highlights: central alpha-2-adrenergic agonist; MedlinePlus: skeletal muscle relaxants. openFDA pharmacologic class could not be retrieved (request blocked in browser).
Class source urls
  • https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=433ac98f-ac22-44ad-a8b4-5db5560b9d0f&type=display
  • https://medlineplus.gov/druginfo/meds/a601121.html
Note
No candidates named because none could be sourced. No recommendation is made.

Frequently asked questions

Question
What is tizanidine used for?
Answer
The label says tizanidine tablets are indicated for the treatment of spasticity in adults. MedlinePlus says it relieves muscle spasms, cramping and tightness from conditions including multiple sclerosis and spinal injury.
Source section
1 INDICATIONS AND USAGE; MedlinePlus
Source
DailyMed Rising label; MedlinePlus
Question
How is tizanidine dosed?
Answer
The label's starting dose is 2 mg by mouth every 6 to 8 hours as needed, up to three doses in 24 hours. It can be increased every 1 to 4 days by 2 mg to 4 mg per dose, and the maximum total daily dosage is 36 mg.
Source section
2.2
Source
DailyMed Rising label
Question
Can I take tizanidine with food?
Answer
Yes. Tablets may be taken with or without food, but the label recommends consistent administration with respect to food. Switching between with and without food, or between tablets and capsules, changes how the drug is absorbed.
Source section
2.2; 2.6
Source
DailyMed Rising label
Question
What should I do if I miss a dose?
Answer
The label text read gives no missed-dose instructions. MedlinePlus says if your doctor told you to take it regularly, take the missed dose as soon as you remember, but if it is almost time for your next dose, skip the missed dose, and do not take a double dose.
Source section
MedlinePlus: forget a dose
Source
MedlinePlus
Question
What are the most common side effects?
Answer
The label lists dry mouth, somnolence, asthenia and dizziness as the most common (greater than 10% of patients taking tizanidine and greater than in patients taking placebo).
Source section
Highlights; 6.1
Source
DailyMed Rising label
Question
Can I drink alcohol with tizanidine?
Answer
The label says alcohol increases tizanidine exposure and was associated with more adverse reactions, and the sedating effects add up. MedlinePlus says alcohol can add to the drowsiness.
Source section
7.4; MedlinePlus
Source
DailyMed Rising label; MedlinePlus
Question
Which medicines must not be taken with tizanidine?
Answer
The label contraindicates strong CYP1A2 inhibitors, with fluvoxamine and ciprofloxacin as examples. It says moderate or weak CYP1A2 inhibitors, including cimetidine, famotidine, oral contraceptives and acyclovir, should be avoided.
Source section
4; 7.1; 7.2
Source
DailyMed Rising label
Question
Can I stop tizanidine suddenly?
Answer
No. The label says stopping can cause rebound hypertension, tachycardia and hypertonia, and the dosage should be decreased slowly. MedlinePlus says not to stop without talking to your doctor.
Source section
5.6; 2.5; MedlinePlus
Source
DailyMed Rising label; MedlinePlus

Sources

Information is taken from the cited sources and is for general reference only. It is not medical advice. Report side effects to FDA MedWatch at 1-800-FDA-1088. For a poison emergency call 1-800-222-1222. See prices for this drug