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Mecamylamine Side Effects

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.

Severity: Major

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

Severity: Minor

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

Nervous system

Frequency not reported: Orthostatic dizziness and syncope, convulsions, choreiform movements, mental aberrations, tremor, paresthesias, sedation[Ref]


Frequency not reported: Ileus, constipation, vomiting, nausea, glossitis, dry mouth[Ref]


Frequency not reported: Urinary retention, impotence[Ref]


Frequency not reported: Blurred vision, dilated pupils[Ref]


Frequency not reported: Weakness, fatigue[Ref]


Frequency not reported: Interstitial pulmonary edema and fibrosis[Ref]


Frequency not reported: Postural hypotension[Ref]


Frequency not reported: Anorexia[Ref]


Frequency not reported: Decreased libido[Ref]


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

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.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.