Generic Name: Mecamylamine.

Trade Name   : Inversine.

Drug Class     : Ganglionic Blockers, Antihypertensives.

Forms of The Drug

  • Tablet: 2.5mg.

Mechanism of Action

The mechanism of action of Mecamylamine revolves around its ability to block the effects of acetylcholine, a neurotransmitter, on nicotinic receptors in the nervous system. Here’s a breakdown of the mechanism of action of Mecamylamine:

  1. Nicotinic Acetylcholine Receptors (nAChRs): Nicotinic acetylcholine receptors are ion channels found on the surfaces of neurons and other cells throughout the nervous system. They are activated by the binding of acetylcholine, a neurotransmitter released at nerve synapses. Activation of these receptors leads to the influx of cations, primarily sodium and calcium ions, into the cell, which generates an excitatory response.
  2. Binding and Antagonism: Mecamylamine works by binding to these nicotinic acetylcholine receptors, specifically to the receptor’s ion channel pore. However, unlike acetylcholine, Mecamylamine does not activate the receptor but instead blocks the channel’s ability to allow ions to pass through. This antagonist action prevents the influx of cations into the neuron, thereby reducing the excitatory response that would normally occur upon acetylcholine binding.
  3. Neurotransmission Inhibition: By blocking the effects of acetylcholine on nicotinic receptors, Mecamylamine reduces the overall excitatory transmission within the nervous system. This leads to a decrease in nerve signal propagation and subsequent physiological effects mediated by nicotinic receptors. In the context of hypertension treatment, this leads to a reduction in sympathetic nervous system activity, helping to lower blood pressure.
  4. Clinical Applications: Due to its ability to block nicotinic receptors, Mecamylamine has been studied for various clinical applications. Apart from its use as an antihypertensive, it has been explored as an aid in smoking cessation. By antagonizing the effects of nicotine on the brain’s reward pathways, Mecamylamine can reduce the pleasurable sensations associated with smoking. Additionally, it has shown promise in treating certain neurological conditions such as Tourette’s syndrome and some forms of depression.

Indications

  1. Hypertension.
  2. Smoking Cessation.
  3. Tourette’s Syndrome.
  4. Depression.

Contraindications

  1. Hypersensitivity to Mecamylamine.
  2. Peptic Ulcer Disease.
  3. Intestinal Obstruction or Paralytic Ileus.
  4. Urinary Retention.
  5. Glaucoma.
  6. Severe Renal Impairment.
  7. Severe Hepatic Impairment.
  8. Pregnancy and Breastfeeding.

Side Effects

  1. Orthostatic hypotension.
  2. Dizziness, lightheadedness.
  3. Fatigue.
  4. Sedation.
  5. Constipation.
  6. Dry mouth.
  7. Nausea/Vomiting.
  8. Xerostomia.
  9. Syncope.
  10. Seizure.
  11. Tremor.
  12. Paralytic ileus.
  13. Chorea.
  14. Dysuria.

Drug interaction

Other drugs that can interact with it.

  1. Antihypertensive Agents.
  2. Barbiturates and Sedative-Hypnotics: Concurrent use of Mecamylamine with barbiturates (e.g., phenobarbital) or sedative-hypnotic medications.
  3. Alcohol and Central Nervous System Depressants: Combining Mecamylamine with alcohol or other central nervous system depressants (such as benzodiazepines or opioids).
  4. Monoamine Oxidase Inhibitors (MAOIs).
  5. Sympathomimetic Agents: Sympathomimetic drugs (e.g., epinephrine, pseudoephedrine).
  6. Nicotine Replacement Therapies.
  7. Food Interactions.

Precautions

  1. Pregnancy: Category C.
  2. Lactation: Mecamylamine is excreted in breast milk, and its potential impact on a nursing infant is not well understood. Since Mecamylamine can cross into breast milk, there is a possibility that it could affect the nursing infant’s nervous system, particularly due to its antagonistic effects on nicotinic acetylcholine receptors.

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