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Generic name: mecamylamine [ meck-a-MILL-a-meen ]
Brand names: Vecamyl, Inversine
Dosage form: oral tablet (2.5 mg)
Drug class: Antiadrenergic agents, peripherally acting

Medically reviewed by on Nov 24, 2023. Written by Cerner Multum.

What is mecamylamine?

Mecamylamine is used to treat moderate to severe hypertension (high blood pressure). Because of its many side effects, mecamylamine is not commonly used.

Mecamylamine is also used to treat malignant hypertension (extremely high blood pressure that comes on suddenly). Malignant hypertension can damage organs in the body if left untreated.

Mecamylamine may also be used for purposes not listed in this medication guide.

Mecamylamine side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Mecamylamine may cause serious side effects. Call your doctor at once if you have:

Common side effects of mecamylamine may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Before taking this medicine

You should not use mecamylamine if you are allergic to it, or if you have:

Some drugs should not be used together with mecamylamine. Your doctor may change your treatment plan if you also use an antibiotic or sulfa drug.

Tell your doctor if you have ever had:

It is not known whether mecamylamine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

You should not breastfeed while using mecamylamine.

How should I take mecamylamine?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Take mecamylamine after meals.

Allow for the same time interval between your meals and your mecamylamine doses. For example, if you take your medicine 15 minutes after eating, take it that way each time.

You may need different amounts of this medicine at different times of the day. Follow your doctor's dosing instructions very carefully. Do not change your dose or stop taking the medicine without your doctor's advice.

Your blood pressure will need to be checked often and you may need other medical tests.

Call your doctor at once if you have a fever, if you are sick with vomiting or diarrhea, or if you are sweating more than usual.

If you need surgery, tell your surgeon you currently use this medicine.

You should not stop using mecamylamine suddenly. Stopping suddenly may make your condition worse.

Store at room temperature away from moisture and heat.

Mecamylamine dosing information

Usual Adult Dose for Hypertension:

2.5 mg orally twice a day; may increase by one 2.5 mg tablet at intervals of 2 days or more until desired blood pressure response is achieved.

-The average total daily dose is 25 mg, usually in 3 divided doses; however, 2.5 mg daily may be sufficient. Partial tolerance may develop in certain patients, which requires an increase in the total daily dose.
-Four or more doses may be required when smooth control is difficult to obtain.
-Titration should be determined by blood pressure readings in the erect position at the time of maximal effect of this drug, as well as by signs and symptoms of orthostatic hypotension. In severe or urgent cases, titration at larger increments and shorter intervals may be needed.

Use: Management of moderately severe to severe essential hypertension and uncomplicated cases of malignant hypertension.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include dizziness, weakness, vision problems, fainting, dry mouth, nausea, vomiting, diarrhea, constipation, urination problems, anxiety, or pounding heartbeats.

What should I avoid while taking this mecamylamine?

Avoid becoming overheated or dehydrated during exercise and in hot weather.

Avoid driving or hazardous activity until you know how mecamylamine will affect you. Your reactions could be impaired.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Drinking alcohol with this medicine can cause side effects.

What other drugs will affect mecamylamine?

When you start or stop taking mecamylamine, your doctor may need to adjust the doses of any other blood pressure medicines you take on a regular basis.

Tell your doctor about all your other medicines, especially:

This list is not complete. Other drugs may affect mecamylamine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.