Mecamylamine

Name: Mecamylamine

Pharmacology

Mechanism of Action

Ganglionic blocker, inhibits acetylcholine at autonomic ganglia resulting in decreased blood pressure

Pharmacokinetics

Half-Life: 24 hr

Onset: 0.5-2 hr

Duration: 6-12 hr

Excretion: urine 100%

Patient Handout

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Who should not take mecamylamine?

Before taking this medication, tell your doctor if you

  • have arteriosclerosis (poor blood flow in the arteries, or "hardening of the arteries") in your heart (coronary) or to the head (cerebral);

  • have recently had a heart attack;

  • have glaucoma;

  • have kidney disease; or

  • have difficulty urinating as a result of an enlarged prostate or some other cause.

You may not be able to take mecamylamine, or you may require a lower dose or special monitoring during treatment if you have any of the conditions listed above.

Mecamylamine is in the FDA pregnancy category C. This means that it is not known whether mecamylamine will harm an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant.

It is not known whether mecamylamine passes into breast milk. Do not take mecamylamine without first talking to your doctor if you are breast-feeding a baby.

Uses of Mecamylamine

  • It is used to treat high blood pressure.
  • It may be given to you for other reasons. Talk with the doctor.

What do I need to tell my doctor BEFORE I take Mecamylamine?

  • If you have an allergy to mecamylamine or any part of this medicine.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you have any of these health problems: A type of stomach or bowel problem called pyloric stenosis, glaucoma, heart blood vessel problems, or kidney problems.
  • If your high blood pressure is under control or is not very high.
  • If you have had a recent heart attack.

This is not a list of all drugs or health problems that interact with mecamylamine.

Tell the doctor and pharmacist about all of your child's drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for your child to take this medicine with all of his/her drugs and health problems. Do not start, stop, or change the dose of any drug your child takes without checking with the doctor.

Onset of Action

0.5 to 2 hours

Dosing Adult

Hypertension: Oral: Initial: 2.5 mg twice daily; may increase by increments of 2.5 mg at intervals ≥2 days until desired blood pressure response is achieved; average dose: 25 mg/day (usually in 3 divided doses; range of 2 to 4 divided doses or more may be required). Note: A small dose and sometimes no dose at all, should be administered in the morning as the blood pressure response is heightened early in the day. The larger dose should be given at noontime or the evening.

Concomitant therapy: When coadministered with thiazide diuretics, decrease the dose of mecamylamine by ≥50%

Dosing Geriatric

Refer to adult dosing.

Dosing Renal Impairment

There are no dosage adjustments provided in the manufacturer's labeling; use with caution; use with extreme caution, if at all, if renal impairment is manifested by a rising or elevated BUN. Use is contraindicated in uremia.

Adverse Reactions

Frequency not defined.

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

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your child's doctor or get medical help right away if your child has any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Blurred eyesight.
  • A burning, numbness, or tingling feeling that is not normal.
  • Lowered interest in sex.
  • Change in sex ability.
  • Very bad dizziness or passing out.
  • Loose stools that happen often.
  • Swelling of belly.
  • Mood changes.
  • Mouth or tongue irritation.
  • Seizures.
  • Very hard stools (constipation).
  • Very bad belly pain.
  • Shortness of breath.
  • Trouble passing urine.
  • Stiff muscles, shakiness, or muscle movements that are not normal.
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