Vecamyl (mecamylamine HCl 2.5 mg)

DESCRIPTION: Mecamylamine HCl is a potent, oral antihypertension agent and ganglion blocker, and is a secondary amine.
CLINICAL PHARMACOLOGY: Mecamylamine HCl reduces blood pressure in both normotensive and hypertensive individuals. It has a gradual onset of action (1/2 to 2 hours) and a long-lasting effect (usually 6 to 12 hours or more). A small oral dosage often produces a smooth and predictable reduction of blood pressure. Although this antihypertensive effect is predominantly orthostatic, the supine blood pressure is also significantly reduced.

Therapy is usually started with one 2.5 mg tablet of Mecamylamine HCl twice a day. This initial dosage should be modified by increments of one 2.5 mg tablet at intervals of not less than 2 days until the desired blood pressure response occurs (the criterion being a dosage just under that which causes signs of mild postural hypotension).

The average total daily dosage of Mecamylamine HCl is 25 mg, usually in three divided doses. However, as little as 2.5 mg daily may be sufficient to control hypertension in some patients. A range of two to four or even more doses may be required in severe cases when smooth control is difficult to obtain. In severe or urgent cases, larger increments at smaller intervals may be needed. Partial tolerance may develop in certain patients, requiring an increase in the daily dosage of Mecamylamine HCl.

Administration of Mecamylamine HCl after meals may cause a more gradual absorption and smoother control of excessively high blood pressure. The timing of doses in relation to meals should be consistent. Since the blood pressure response to antihypertensive drugs is increased in the early morning, the larger dose should be given at noontime and perhaps in the evening. The morning dose, as a rule, should be relatively small and in some instances may even be omitted.

The initial regulation of dosage should be determined by blood pressure readings in the erect position at the time of maximal effect of the drug, as well as by other signs and symptoms of orthostatic hypotension. The effective maintenance dosage should be regulated by blood pressure readings in the erect position and by limitation of dosage to that which causes slight faintness or dizziness in this position. If the patient or a relative can use a sphygmomanometer, instructions may be given to reduce or omit a dose if readings fall below a designated level or if faintness or lightheadedness occurs. However, no change should be instituted without the knowledge of the physician.

Close supervision and education of the patient, as well as critical adjustment of dosage, are essential to successful therapy.
WARNINGS: When Mecamylamine HCl is withdrawn, this should be done gradually and other antihypertensive therapy usually must be substituted.

Signs of overdosage include: hypotension (which may progress to peripheral vascular collapse), postural hypotension, nausea, vomiting, diarrhea, constipation, paralytic ileus, urinary retention, dizziness, anxiety, dry mouth, mydriasis, blurred vision, or palpitations. A rise in intraocular pressure may occur. Pressor amines may be used to counteract excessive hypotension. Since patients being treated with ganglion blockers are more than normally reactive to pressor amines, small doses of the latter are recommended to avoid excessive response.
The oral LD50 of Mecamylamine HCl in the mouse is 92 mg/kg.
Poison control 1-800-222-1222 (RxDiff standard; not in the label text).

HOW SUPPLIED: Vecamyl® (MECAMYLAMINE Hydrochloride Tablets, USP) are slightly yellow, round, compressed tablets, coded MP on one side and 2.5 on the other side. They are supplied as follows: NDC 83649-558-01 in bottles of 100.
STORAGE CONDITION: Store at 20°C to 25°C (68°F to 77°F) excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature.] Dispense in a tight container.

Pregnancy Category C. Animal reproduction studies have not been conducted with Mecamylamine HCl. It is not known whether Mecamylamine HCl can cause fetal harm when given to a pregnant woman or can affect reproductive capacity. Mecamylamine HCl should be given to a pregnant woman only if clearly needed.
Nursing Mothers: Because of the potential for serious adverse reactions in nursing infants from Mecamylamine HCl, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
CLINICAL PHARMACOLOGY: Mecamylamine HCl crosses the blood-brain and placental barriers.