mecamylamine
Mecamylamine, also known by its brand name Vecamyl, is an older prescription medication that's FDA approved to treat moderately severe to severe high blood pressure and some cases of life-threatening high blood pressure. It comes as a tablet that's taken by mouth up to 3 times a day. Mecamylamine (Vecamyl) isn't commonly used anymore because it has many side effects and newer, safer blood pressure medications are now available. It can also interact with several medications. Side effects include dizziness, constipation, and blurry vision.
What is Mecamylamine (Vecamyl)?
What is Mecamylamine (Vecamyl) used for?
Moderately severe to severe high blood pressure
Life-threatening high blood pressure without complications
How Mecamylamine (Vecamyl) works
Mecamylamine (Vecamyl) is a ganglion blocker. It works by locking nerve singles that use a chemical called acetylcholine. This helps relax your blood vessels and reduces how hard your heart works, which lowers your blood pressure.
Drug Facts
What are the side effects of Mecamylamine (Vecamyl)?
Common Side Effects
- Dizziness
- Fainting
- Lightheadedness
- Tiredness
Other Side Effects
- Blurry vision
- Dry mouth
- Constipation
- Nausea
- Vomiting
- Trouble urinating
- Reduced sex drive
Serious Side Effects
- Nervous system side effects: seizures, confusion, tremors, involuntary movements, changes in thinking
- Intestinal blockage: frequent diarrhea, stomach bloating, less stomach rumbling
Source: DailyMed
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- Constipation, bloating, nausea or vomiting, stomach pain, which may be signs of slow movement through the digestive tract
- Low blood pressure—dizziness, feeling faint or lightheaded, blurry vision
- New or worsening uncontrolled and repetitive movements of the face, mouth, or upper body
- Tremors or shaking
- Trouble passing urine
- Unusual changes in behavior
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
Pros and cons of Mecamylamine (Vecamyl)
Pros
Works within 30 minutes to 2 hours
Can last for up to 12 hours or more
Taken by mouth
Cons
Not a first-choice option to treat severe high blood pressure
Commonly causes dizziness, blurred vision, and constipation
Might need to take three times per day
Pharmacist tips for Mecamylamine (Vecamyl)
Take mecamylamine (Vecamyl) by mouth with or without food. Taking it after meals can help your body absorb the medication more gradually for smoother blood pressure control. But it's more important to take it the same way each time — either always with food or always without.
Take mecamylamine (Vecamyl) exactly as prescribed. Don't change your dose or stop taking it suddenly without talking to your prescriber. Doing so can cause your blood pressure to rise quickly. Your prescriber might need to lower your dose gradually before you stop taking it completely.
Check your blood pressure at home regularly and write down your readings. Share these with your prescriber during follow-up visits to see if the medication is working for you and if your treatment plan needs adjustments.
Mecamylamine (Vecamyl) can cause dizziness and lightheadedness, especially when you first start taking the medication or when your dose is raised. To prevent falls, stand up slowly after sitting or lying down.
Ask your prescriber if a low-salt diet is right for you. Eating less salt can make mecamylamine (Vecamyl) work stronger. Tell your prescriber if you have diarrhea, vomiting, heavy sweating, or take diuretics (water pills), as these can lower your body’s salt levels.
Mecamylamine (Vecamyl) can interact with many medications. Be sure to tell your care team about all the medications you’re taking before and during treatment, especially if you take other medications that lower your blood pressure.
It's best to avoid alcohol with mecamylamine (Vecamyl) because it can lower your blood pressure, causing dizziness and falls. It can also worsen side effects like sleepiness, dizziness, and blurry vision.
Let your prescriber know your exercise routine and report any infections, fevers, or bleeding during treatment with mecamylamine (Vecamyl). These can make the medication’s effects stronger and raise your risk of side effects.
If you experience repeated diarrhea or stomach bloating after starting mecamylamine (Vecamyl), contact your prescriber right away. This could be a sign of a serious bowel issue.
If you're pregnant, thinking of getting pregnant, or breastfeeding and are taking mecamylamine (Vecamyl), let your prescriber know. They might recommend other medications that are safer during pregnancy or breastfeeding.
Frequently asked questions about Mecamylamine (Vecamyl)
How to save using GoodRx
What are the risks and warnings for Mecamylamine (Vecamyl)?
Mecamylamine (Vecamyl) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Nervous system side effects
Risk factors: Taking higher doses of mecamylamine (Vecamyl) | Kidney problems | Brain problems
Mecamylamine (Vecamyl) can reach the brain and can cause nervous system side effects, though these are rare. They're more likely to happen if you have kidney problems or certain brain conditions. Get medical help if you have convulsions (sudden shaking), as this could be a sign of a seizure. Let your prescriber know right away if you experience confusion, tremors, or involuntary movements.
Sudden high blood pressure after stopping
If you stop taking ganglion blockers like mecamylamine (Vecamyl) suddenly, your blood pressure can rise to dangerous levels. This sudden change can cause serious problems, such as a stroke or heart failure. To prevent this, your prescriber will gradually lower your dose of mecamylamine (Vecamyl) and usually switch you to another blood pressure medication. Always follow your prescriber’s instructions when stopping or changing medications.
Low blood pressure
Risk factors: Problems with blood flow in the body | Excessive heat | Fever | Infection | Bleeding | Pregnancy | Anesthesia and surgery | Intense exercise | Alcohol use | Taking other blood pressure medications | Low salt levels in your body | Excessive sweating | Having diarrhea or vomiting
Taking mecamylamine (Vecamyl) can sometimes lower your blood pressure too much. This might happen more easily in certain situations, like being in excessive heat, having a fever or infection, bleeding, pregnancy, anesthesia, surgery, intense exercise, drinking alcohol, or taking other blood pressure medications. Make sure to stay well-hydrated. If your blood pressure drops too low and you feel dizzy, sit down slowly and hold onto something stable. Contact your care team if this happens. If you fall and hit your head, get medical help right away.
Trouble urinating
Risk factors: Enlarged prostate | Bladder problems
Mecamylamine (Vecamyl) can cause trouble urinating (urinary retention). The risk is higher if you have conditions like an enlarged prostate or bladder problems. Let your prescriber know if you have symptoms such as difficulty passing urine, urgency, or weak urine stream.
Intestinal blockage
Frequent diarrhea, stomach bloating, and less stomach rumbling could be early signs of an intestinal blockage while taking mecamylamine (Vecamyl). If you experience these symptoms, stop the medication and let your prescriber know right away.
Mecamylamine (Vecamyl) dosage forms
Typical dosing for Mecamylamine (Vecamyl)
The typical starting dose is 2.5 mg by mouth twice a day. Your prescriber will raise the dose slowly over a few weeks. Most people take 25 mg per day, which is typically split up into three smaller doses throughout the day.
Mecamylamine (Vecamyl) contraindications
Mild or moderate high blood pressure
Recent heart attack or coronary artery disease
Uremia (a serious kidney condition)
Taking antibiotics and sulfonamides
Pyloric stenosis (narrowing of the opening from the stomach to the intestines)
What are alternatives to Mecamylamine (Vecamyl)?
Moderately severe to severe high blood pressure
Life-threatening high blood pressure without complications
Get savings updates for Mecamylamine (Vecamyl)
Receive price alerts, news, and other messages from GoodRx about Mecamylamine (Vecamyl) and other healthcare topics and relevant savings offers.By signing up, I agree to GoodRx's Terms and Privacy Policy, and to receive marketing messages from GoodRx.
References
Best studies we foundGarfield, K., et al. (2023). Pyloric stenosis.
Lancaster, T., et al. (2000). Mecamylamine (a nicotine antagonist) for smoking cessation. The Cochrane Database of Systematic Reviews.
LGM Pharma Solutions, LLC. (2024). Mecamylamine hydrochloride tablet [package insert]. DailyMed.
PubChem. (n.d.). Mecamylamine.
Roberts, W., et al. (2018). Tobacco use during a clinical trial of mecamylamine for alcohol dependence: Medication effects on smoking and associations with reductions in drinking. Journal of Substance Abuse Treatment.
Sam, C., et al. (2023). Physiology, acetylcholine. StatPearls.
Shytle, R. D., et al. (2002). Mecamylamine (Inversine): An old antihypertensive with new research directions. Journal of Human Hypertension.
Tiwari, R. K., et al. (2020). Nicotine addiction: Neurobiology and mechanism. Journal of Pharmacopuncture.
U.S. Department of Health and Human Services. (2004). The Seventh Report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure.
Young, J. M., et al. (2001). Mecamylamine: New therapeutic uses and toxicity/risk profile. Clinical Therapeutics.
Zemaitis, M. R., et al. (2024). Uremia. StatPearls.
Browse medications
View AllResearch prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.