What is Demser? Uses, warnings & side effects

Updated May 14, 2025  •  Published Apr 11, 2021

Demser overview

BRAND NAMES:

  • Demser

Generic Names:

  • Demser

Uses:

  • Treats symptoms caused by pheochromocytoma (tumor of the adrenal gland). Used before surgery that removes adrenal gland tumors.

Therapeutic Classes:

  • Antihypertensive

Forms:

  • Capsule

How it’s taken:

  • By mouth

What is Demser used for?

Demser is used by patients with pheochromocytoma to treat their condition. Demser works by decreasing the hormones made by the tumor in the infected adrenal gland. This prescription-only medication manages hypertension levels in pheochromocytoma patients before undergoing a medical procedure.

What form(s) does Demser come in?

  • Capsule

What are common Demser dosages?

  • Capsule 250MG

How to take Demser

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.

  • Drink extra liquids so you will pass more urine while you are taking this medicine. This will keep crystals from forming in your urine.

What to do if you miss a dose of Demser

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.

Demser contraindications - Who shouldn't take Demser?

  • You should not take this medicine if you have had an allergic reaction to metyrosine (Demser®).

Demser warnings

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Make sure your doctor knows if you are pregnant or breast feeding, or if you have heart, kidney, or liver problems.

  • After you have stopped using this medicine, you may have trouble falling asleep at night and have an unusually high energy level. These feelings may last for 2 or 3 days.

  • This medicine may make you drowsy. Avoid driving, using machines, or doing anything else that may be dangerous if you are not alert.

  • Make sure any doctor who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.

Demser interactions & what to avoid when taking Demser

  • After you have stopped using this medicine, you may have trouble falling asleep at night and have an unusually high energy level. These feelings may last for 2 or 3 days.

  • Make sure your doctor knows if you are also using phenothiazines, such as prochlorperazine, Compazine®, Mellaril®, Phenergan®, Thorazine®, or Trilafon®, or if you are also using haloperidol (Haldol®).

  • Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.

  • Avoid drinking alcohol while you are using this medicine.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

Demser side effects - How does Demser make you feel?

Serious Side Effects

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

  • Stuffy nose.

  • Swelling or tenderness in your hands or feet.

  • Swollen breasts, or liquid discharge from your nipples.

  • Blood in your urine, or painful urination.

  • Difficulty speaking.

  • Drooling, or dry mouth.

  • Feeling unusually sleepy or tired.

  • Feeling unusually sad, anxious, or confused.

  • Headache.

  • Men: unable to have or keep an erection.

  • Nausea, stomach pain, vomiting, or diarrhea.

  • Seeing or hearing things that are not there.

  • Shaking or twitching of your hands or other body parts.

Less Serious Side Effects

  • Feeling unusually sleepy or tired.

  • Blood in your urine, or painful urination.

  • Shaking or twitching of your hands or other body parts.

  • Men: unable to have or keep an erection.

  • Swelling or tenderness in your hands or feet.

  • Difficulty speaking.

  • Seeing or hearing things that are not there.

  • Bleeding or bruising easily.

  • Drooling, or dry mouth.

  • Headache.

  • Swollen breasts, or liquid discharge from your nipples.

  • Nausea, stomach pain, vomiting, or diarrhea.

  • Stuffy nose.

  • Feeling unusually sad, anxious, or confused.

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