Generic Name

Mecamylamine Hydrochloride

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Classification

FDA Approved Indications

• Hypertension (off-label use commonly for nicotine addiction or other conditions)

Mechanism of Action

Mecamylamine is a non-selective antagonist of nicotinic acetylcholine receptors at autonomic ganglia, leading to inhibition of sympathetic and parasympathetic neurotransmission, which results in lowered blood pressure.

Dosage and Administration

Adult: Typically, 10-30 mg per day in divided doses, titrated based on response and tolerability.

Pediatric: Use is generally not recommended due to limited data.

Geriatric: Start at lower doses due to increased sensitivity and risk of side effects.

Renal Impairment: Use with caution; dosage adjustments may be necessary.

Hepatic Impairment: Use with caution; monitor closely.

Pharmacokinetics

Absorption: Well absorbed from the gastrointestinal tract.

Distribution: Widely distributed, crosses the blood-brain barrier.

Metabolism: Metabolized minimally in the liver.

Excretion: Excreted primarily via kidneys in unchanged form.

Half Life: Approximately 10-24 hours, allowing for once or twice daily dosing.

Contraindications

• Known hypersensitivity to mecamylamine or other ganglionic blockers.

Precautions

• Use with caution in patients with psychiatric disorders, cardiovascular disease, or history of cerebrovascular disease.

Adverse Reactions - Common

• Orthostatic hypotension (Common)
• Headache (Common)
• Dizziness (Common)

Adverse Reactions - Serious

• Neuropsychiatric symptoms (depression, hallucinations) (Less common)
• Gastrointestinal disturbances (nausea, vomiting) (Less common)
• Severe hypotension or hypertensive crisis in overdose (Serious)

Drug-Drug Interactions

• Other antihypertensives (additive hypotension)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Do not stop medication abruptly.
• Rise slowly from sitting or lying position to prevent orthostatic hypotension.
• Report any mental changes, severe dizziness, or signs of depression.

Special Considerations

Black Box Warnings:

• Use with caution in patients with psychiatric disorders.
• Monitor for neuropsychiatric adverse effects.

Genetic Factors: None established.

Lab Test Interference: May cause false positives in certain drug screening tests for nicotine.

Overdose Management

Signs/Symptoms: Severe hypotension, coma, muscle weakness, sedation.

Treatment: Supportive care, intravenous fluids, vasopressors if needed, activated charcoal if ingestion was recent.

Storage and Handling

Storage: Store at room temperature, away from moisture and light.

Stability: Stable under recommended storage conditions.