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Mecamylamine Side Effects

Not all side effects for mecamylamine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to mecamylamine: oral tablet

In addition to its needed effects, some unwanted effects may be caused by mecamylamine. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking mecamylamine:

More common
  • Dizziness or lightheadedness, especially when getting up suddenly from a lying or sitting position
Less common
  • Difficult urination
  • Bloating and frequent loose stools
  • confusion or excitement
  • constipation (severe)
  • convulsions (seizures)
  • mental depression
  • shortness of breath
  • trembling
  • uncontrolled movements of the face, hands, arms, or legs

Some of the side effects that can occur with mecamylamine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Constipation
  • drowsiness
  • unusual tiredness
Less common or rare
  • Blurred vision
  • decreased sexual ability or interest in sex
  • dryness of the mouth
  • enlarged pupils
  • loss of appetite
  • nausea and vomiting
  • weakness

For Healthcare Professionals

Applies to mecamylamine: oral tablet


Gastrointestinal side effects have included ileus, constipation (sometimes preceded by small, frequent liquid stools), nausea, vomiting, anorexia, glossitis, and dryness of mouth.[Ref]


Cardiovascular side effects have included orthostatic dizziness and syncope and postural hypotension.[Ref]

Nervous system

Nervous system side effects have included convulsions, choreiform movements, tremor, and paresthesias.[Ref]

These side effects have occurred most often when large doses of mecamylamine were used, especially in patients with cerebral or renal insufficiency.[Ref]


These side effects have occurred most often when large doses of mecamylamine were used, especially in patients with cerebral or renal insufficiency.[Ref]

Psychiatric side effects have included mental aberrations.[Ref]


Respiratory side effects have included interstitial pulmonary edema and fibrosis.


Genitourinary side effects have included urinary retention and impotence.[Ref]


Ocular side effects have included blurred vision and dilated pupils.[Ref]


General side effects have included decreased libido, weakness, fatigue, and sedation.[Ref]


1. "Product Information. Inversine (mecamylamine)." Merc & Co Inc, West Point, PA.

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