Metyrosine (Demser) is used to treat symptoms of a rare type of tumor called pheochromocytoma. It’s typically taken 4 times a day by mouth, and comes as both brand-name and generic capsules. The most common side effect is drowsiness, but this usually gets better within a few days of starting the medication.
Treatment of pheochromocytoma for:
Preparation for surgery to remove the tumors
People who aren't able to have surgery
Long-term treatment of people with malignant pheochromocytoma (cancer)
Metyrosine (Demser) is a tyrosine hydroxylase inhibitor, meaning it blocks a protein in the body called tyrosine hydroxylase. This protein is responsible for making hormones called catecholamines.
People who have pheochromocytoma have tumors that make too many of these catecholamines. So metyrosine (Demser) works by lowering the amount of catecholamines that are made. This can reduce the symptoms like high blood pressure, headaches, sweating, and a fast heart beat.
Source:Â DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
Less common
confusion
hallucinations (seeing, hearing, or feeling things that are not there)
mental depression
Rare
Black, tarry stools
blood in urine or stools
unusual bleeding or bruising
muscle spasms, especially of neck and back
pinpoint red spots on skin
restlessness
shortness of breath
shuffling walk
skin rash and itching
swelling of feet or lower legs
tic-like (jerky) movements of head, face, mouth, and neck
unusual tiredness or weakness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Drowsiness
After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, check with your doctor immediately if you notice the following side effects:
More common
Also, after you stop taking this medicine, you may have feelings of increased energy or you may have trouble sleeping. However, these effects should last only for two or three days.
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Dose can be adjusted based on your response to the medication
A good option for people who can't have surgery
Can work well to lower the amount of hormones causing symptoms
Can be added to other pheochromocytoma treatments like phenoxybenzamine (Dibenzyline)
Available as a lower-cost generic
Must be taken 4 times a day
Must drink plenty of fluids while taking this medication to lower the risk of kidney stones
Commonly causes drowsiness and diarrhea
Unknown if safe or works well in children under 12 years old
Interacts with many other medications
Set an alarm to help you remember to take all of your doses of metyrosine (Demser) each day.
Drowsiness is a common side effect of metyrosine (Demser). Avoid alcohol and other sedating medications (e.g., sleeping medications, muscle relaxants). Make sure you know how this medication affects you before driving or doing activities that require you to be alert.
It's important to drink plenty of fluids while taking metyrosine (Demser). This will help prevent the medication from forming crystals in your urine, which could lead to kidney stones.
If you experience diarrhea while taking metyrosine (Demser), talk to your provider about ways to manage it if you need to continue taking the medication.
Provide your healthcare team with a current list of your medications. Metyrosine (Demser) can interact with many medications, including phenothiazines and haloperidol (Haldol). Your provider or pharmacist can check to make sure your medications are safe to take together.
After you stop taking metyrosine (Demser), you might experience trouble sleeping and possibly feel even more alert. This effect usually lasts for 2 to 3 days. Don’t stop taking this medication without talking with your provider.
Metyrosine (Demser) 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.
Risk factors: Low fluids in the body | High doses of metyrosine (Demser)
Metyrosine (Demser) can cause crystals to form in the urine, which could lead to problems like kidney stones. Signs of kidney stones include painful urination, fever, and sometimes blood in the urine. The risk is higher if your dose of metyrosine (Demser) is more than 2 grams per day. To lower this risk, make sure you drink plenty of fluids. Your provider will test your urine regularly to make sure you don't have crystals in it.
Metyrosine (Demser) can cause you to feel very sleepy and less alert. This usually happens within the first 24 hours of starting this medication and might get worse for 2 or 3 days. It should get better with time, but if it doesn't, you should let your provider know. Avoid taking this medication with alcohol or other medications like sleeping pills, opioid pain medications, and muscle relaxants. Be sure to know how the medication affects you before driving or performing activities that require you to be alert.
Dosage | Quantity | Price as low as | Price per unit |
---|---|---|---|
250mg | 180 capsules | $17189.10 | $95.49 |
Adults and children 12 years and older: The typical starting dose is 250 mg by mouth 4 times a day. Your provider will adjust your dose based on your response to the medication. The maximum dose is 4 grams per day.
How long you take metyrosine (Demser) depends on what you’re using the medication for.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Treatment of pheochromocytoma for:
Preparation for surgery to remove the tumors
People who aren't able to have surgery
Long-term treatment of people with malignant pheochromocytoma (cancer)
Treatment of high blood pressure or sweating in adults with pheochromocytoma
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Amneal Pharmaceuticals NY LLC. (2023). Metyrosine capsule [package insert]. DailyMed.
D’Souza, R. S., et al. (2023). Extrapyramidal symptoms. StatPearls.
Harari, A., et al. (2011). Malignant pheochromocytoma: A review. The American Journal of Surgery.
Kidron, A., et al. (2023). Phenothiazine. StatPearls.
MedlinePlus. (2016). Pheochromocytoma.
National Cancer Institute. (n.d.). Catecholamine.
National Cancer Institute. (2020). Pheochromocytoma.
You and Your Hormones. (2021). Adrenal glands.
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