This medication is used to treat high blood pressure in people with a certain adrenal gland tumor (pheochromocytoma). Metyrosine is used to prevent high blood pressure before and immediately after surgery to remove the tumor. It is also used long-term in people who cannot have the surgery. It is not used for other kinds of high blood pressure.
Metyrosine prevents the tumor from making certain natural substances (catecholamines) that raise the blood pressure and make the heart beat faster. Lowering the amount of catecholamines lessens the risk of a very serious attack of high blood pressure (hypertensive crisis).
Take this medication by mouth with or without food, usually 4 times a day or as directed by your doctor. The dosage is based on your medical condition and response to treatment. Do not take more than a total of 4 grams each day.
Your doctor may direct you to start taking this drug at a low dose and slowly increase your dose until you are taking the best dose for you. Your doctor will check your blood pressure and order lab tests (e.g., urine tests for catecholamines) to find the best dose.
During treatment with this medication, it is important that you get plenty of fluids and pass urine frequently to help avoid kidney and bladder side effects. Ask your doctor how much fluid you should drink and how often you should urinate each day, and follow these instructions carefully.
Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day. Do not stop taking this medication without consulting your doctor. It is important to continue taking this medication even if you feel well. Most people with high blood pressure do not feel sick. You may have trouble sleeping (insomnia) for 2 to 3 days after you stop taking this medication. Tell your doctor if these symptoms persist or worsen or if you have other symptoms of very high blood pressure (e.g., headache, nausea, sweating, fast heartbeat).
This medication is usually taken for at least 5 to 7 days before surgery.
Drowsiness, tiredness, dizziness, lightheadedness, dry mouth, and diarrhea may occur as your body adjusts to the medication. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To lower your risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if any of these unlikely but serious side effects occur: difficulty speaking, drooling, unwanted/uncontrolled movements, muscle stiffness, shaking (tremor), decrease in sexual ability, tenderness/swelling of the breast.
Tell your doctor right away if any of these rare but very serious side effects occur: mental/mood changes (e.g., confusion, depression, severe anxiety), painful urination, pink/bloody urine, change in the amount of urine.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
In the US -
Before taking metyrosine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before having surgery, tell your doctor or dentist that you are taking this medication.
This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages because alcohol may increase dizziness/drowsiness and may also cause you to lose too much body water (become dehydrated).
During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.
It is not known whether this drug passes into breast milk. Consult your doctor before breast-feeding.
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first.
Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: anti-psychotic medication (e.g., haloperidol, thiothixene), certain drugs (phenothiazines) used to treat mental/mood conditions or nausea (e.g., chlorpromazine, prochlorperazine).
Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-seizure drugs (e.g., carbamazepine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., risperidone, amitriptyline, trazodone).
Check the labels on all your medicines (e.g., cough-and-cold products, diet aids, nonsteroidal anti-inflammatory drugs-NSAIDs such as ibuprofen for pain/fever reduction) because they may contain ingredients that cause drowsiness or could increase your blood pressure. Ask your pharmacist about using those products safely.
Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
If overdose is suspected, contact a poison control center or emergency room right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
Do not share this medication with others.
Laboratory and/or medical tests (e.g., blood pressure, EKG, urine catecholamine tests) should be performed regularly to monitor your progress or check for side effects. Consult your doctor for more details.
Have your blood pressure checked regularly while taking this medication. Learn how to monitor your own blood pressure at home, and share the results with your doctor.
If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.
Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised December 2013. Copyright(c) 2013 First Databank, Inc.
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