Mecamylamine (Vecamyl) is a centrally acting antihypertensive medication that is used in patients with mild to moderate hypertension.

Mecamylamine Uses:

• Hypertension:

  • It is indicated for the management of moderately severe to severe hypertension and in uncomplicated malignant hypertension.

Mecamylamine (Vecamyl) Dose in Adults:

Mecamylamine (Vecamyl) Dose in the treatment of Hypertension:

• Initial: 2.5 mg orally two times a day.
• The dose may be increased by increments of 2.5 mg at intervals 2 days or more until the desired blood pressure response is achieved.
• The average dose is 25 mg/day usually in three divided doses (ranging from 2 to 4 divided doses).

Note:

• The dosing strength should be adjusted to the timings of the day. A smaller dose should be given in the morning. The large dose should be given at noontime or in the evening.
• When the drug is administered with concomitant antihypertensive medications such as thiazide diuretics, the dose should be reduced by 50% or more.

Use in Children:

Not indicated.

Pregnancy Risk Factor C

• It has not been used in animal reproduction studies.
• It can also cross the placental boundary.

Use of mecamylamine during breastfeeding

• Breastfeeding mothers should use it with caution, as there is the possibility of serious adverse drug reactions in their infants.
• Manufacturers recommend that you weigh the benefits and risks of drug therapy for both mother and infant.

Mecamylamine (Vecamyl) Dose in Kidney Disease:

• There are no dosage adjustments provided in the manufacturer's labeling.
• However, it should be used with caution as the excretion of the drug is impaired in renal impairment.
• It is contraindicated in patients with uremia.

Dose in Liver disease:

There are no dosage adjustments provided in the manufacturer's labeling

Side effects of Mecamylamine (Vecamyl):

• Cardiovascular:

  • Orthostatic hypotension
  • Syncope

• Central nervous system:

  • Altered mental status
  • Choreiform movements
  • Convulsions
  • Fatigue
  • Orthostatic dizziness
  • Paresthesia
  • Sedation

• Endocrine & metabolic:

  • Decreased libido

• Gastrointestinal:

  • Anorexia
  • Constipation (sometimes preceded by small, frequent stools)
  • Glossitis
  • Intestinal obstruction
  • Nausea
  • Vomiting
  • Xerostomia

• Genitourinary:

  • Impotence
  • Urinary retention

• Neuromuscular & skeletal:

  • Tremor
  • Weakness

• Ophthalmic:

  • Blurred vision
  • Mydriasis

• Respiratory:

  • Pulmonary edema
  • Pulmonary fibrosis

Contraindication to Mecamylamine (Vecamyl):

• Allergy to mecamylamine and any component of the formulation
• Patients with hypertension, mild, moderate or labile (it might not be suitable to uncooperative patients).
• Patients suffering from coronary insufficiency, recent myocardial injury or other cardiac conditions;
• Uremia;
• Glaucoma;
• Pyloric stenosis
• Coadministration of antibiotics or with sulfonamides

Warnings and precautions

• CNS effects

  • The drug may cause side effects in the central nervous system, such as tremors and choreiform movements, convulsions, and mental aberrations.
  • This is especially true if it is given in high doses or to patients with cerebral or kidney insufficiency.
  • Patients may also experience dizziness, lightheadedness or fainting.

• Paralytic ileus:

  • Paralytic ileus is a condition that causes the patient to stop taking medication. 
  • Paralytic ileus symptoms include frequent loose bowel movements, abdominal distension, reduced borborygmi, and abdominal pain.

• Cardiovascular disease

  • Patients with cerebral or coronary arteriosclerosis, and patients who have had a cerebral accident should use caution.

• Prostatic hyperplasia/urinary restriction:

  • It can cause urinary retention. Patients with bladder outlet obstruction, prostatic hyperplasia, and urethral stricture should not use it.

• Renal impairment

  • If it is used, patients with impaired kidney function should use it with caution.
  • Because the drug is excreted unchanged in the urine, renal impairment could lead to the accumulation of the drug. Hypotension could occur.
  • Patients with severe renal impairment may experience neurological side effects from the drug if they are given too much.

Mecamylamine: Drug Interaction

Monitoring parameters:

• Monitor blood pressure (assess the blood pressure in the erect position before initiating treatment and with dose increases)
• Orthostatic vital signs, and
• Heart rate

How to administer Mecamylamine (Vecamyl)?

It should be administered after meals. Administration after meals may cause a more gradual absorption and smoother control of high blood pressure. The timing of the relationship to meals should be consistent.

Mechanism of action of Mecamylamine (Vecamyl):

• It blocks the acetylcholine receptive at the autonomic glands. 
• These receptors are non-selectively and not-competitively inhibited, resulting in a decrease in blood pressure.
• Although the blood pressure-lowering effect is principally orthostatic, it is also significant for those who are supine.

Onset:

• 0.5 to 2 hours

Duration:

• 6 to 12 hours or more.

Absorption:

• It is almost completely absorbed.

Excretion:

• It is excreted in urine as an unchanged drug.
• The rate of elimination of the drug is significantly affected by urinary PH. Acidic urine promotes its excretion while alkaline PH reduces excretion.

International Brand Names of Mecamylamine:

• Vecamyl

Mecamylamine Brand Names in Pakistan:

No Brands Available in Pakistan.