Metyrosine
Generic Name: metyrosine
Brand Names:
Metyrosine
DESCRIPTION Metyrosine is (–)-α-methyl- L -tyrosine or (α-MPT). It has the following structural formula: Metyrosine USP is a white to off-white, crystalline compound of molecular weight 195.22. It is very slightly soluble in water, acetone, and methanol, and insoluble in chloroform and benzene. It is soluble in acidic aqueous solutions. It is also soluble in alkaline aqueous solutions but is subject to oxidative degradation under these conditions.
Overview
DESCRIPTION Metyrosine is (–)-α-methyl- L -tyrosine or (α-MPT). It has the following structural formula: Metyrosine USP is a white to off-white, crystalline compound of molecular weight 195.22. It is very slightly soluble in water, acetone, and methanol, and insoluble in chloroform and benzene. It is soluble in acidic aqueous solutions. It is also soluble in alkaline aqueous solutions but is subject to oxidative degradation under these conditions.
Uses
INDICATIONS AND USAGE Metyrosine capsules are indicated in the treatment of patients with pheochromocytoma for: Preoperative preparation of patients for surgery Management of patients when surgery is contraindicated Chronic treatment of patients with malignant pheochromocytoma Metyrosine capsules are not recommended for the control of essential hypertension.
Dosage
DOSAGE AND ADMINISTRATION The recommended initial dosage of metyrosine capsules for adults and children 12 years of age and older is 250 mg orally four times daily. This may be increased by 250 mg to 500 mg every day to a maximum of 4 g/day in divided doses. When used for preoperative preparation, the optimally effective dosage of metyrosine capsules should be given for at least five to seven days. Optimally effective dosages of metyrosine usually are between 2 and 3 g/day, and the dose should be titrated by monitoring clinical symptoms and catecholamine excretion. In patients who are hypertensive, dosage should be titrated to achieve normalization of blood pressure and control of clinical symptoms.
Side Effects
ADVERSE REACTIONS Central Nervous System Sedation: The most common adverse reaction to metyrosine is moderate to severe sedation, which has been observed in almost all patients. It occurs at both low and high dosages. Sedative effects begin within the first 24 hours of therapy, are maximal after two to three days, and tend to wane during the next few days. Sedation usually is not obvious after one week unless the dosage is increased, but at dosages greater than 2,000 mg/day some degree of sedation or fatigue may persist. In most patients who experience sedation, temporary changes in sleep pattern occur following withdrawal of the drug. Changes consist of insomnia that may last for two or three days and feelings of increased alertness and ambition.
Interactions
Drug Interactions Caution should be observed in administering metyrosine to patients receiving phenothiazines or haloperidol because the extrapyramidal effects of these drugs can be expected to be potentiated by inhibition of catecholamine synthesis. Concurrent use of metyrosine with alcohol or other CNS depressants can increase their sedative effects. (See WARNINGS and PRECAUTIONS , Information for Patients .)
Warnings
WARNINGS Maintain Fluid Volume During and After Surgery When metyrosine is used preoperatively, alone or especially in combination with alphaadrenergic blocking drugs, adequate intravascular volume must be maintained intraoperatively (especially after tumor removal) and postoperatively to avoid hypotension and decreased perfusion of vital organs resulting from vasodilatation and expanded volume capacity. Following tumor removal, large volumes of plasma may be needed to maintain blood pressure and central venous pressure within the normal range. In addition, life-threatening arrhythmias may occur during anesthesia and surgery, and may require treatment with a beta-blocker or lidocaine. During surgery, patients should have continuous monitoring of blood pressure and electrocardiogram. CONTRAINDICATIONS Metyrosine capsules are contraindicated in persons known to be hypersensitive to this compound.
Pregnancy
Pregnancy Pregnancy: Animal reproduction studies have not been conducted with metyrosine. It is also not known whether metyrosine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Metyrosine should be given to a pregnant woman only if clearly needed.
Storage
Storage: Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature]. Dispense in a well-closed container. Manufactured by: Cerovene Inc. Valley Cottage, NY 10989 Manufactured For: Dr. Reddy's Laboratories Inc. Princeton, NJ 08540 USA Issued: 03/2024 CEROVENE
Frequently Asked Questions
What is Metyrosine used for?▼
INDICATIONS AND USAGE Metyrosine capsules are indicated in the treatment of patients with pheochromocytoma for: Preoperative preparation of patients for surgery Management of patients when surgery is contraindicated Chronic treatment of patients with malignant pheochromocytoma Metyrosine capsules are not recommended for the control of essential hypertension.
What are the side effects of Metyrosine?▼
ADVERSE REACTIONS Central Nervous System Sedation: The most common adverse reaction to metyrosine is moderate to severe sedation, which has been observed in almost all patients. It occurs at both low and high dosages. Sedative effects begin within the first 24 hours of therapy, are maximal after two to three days, and tend to wane during the next few days. Sedation usually is not obvious after one week unless the dosage is increased, but at dosages greater than 2,000 mg/day some degree of sedation or fatigue may persist. In most patients who experience sedation, temporary changes in sleep pattern occur following withdrawal of the drug. Changes consist of insomnia that may last for two or three days and feelings of increased alertness and ambition.
Can I take Metyrosine during pregnancy?▼
Pregnancy Pregnancy: Animal reproduction studies have not been conducted with metyrosine. It is also not known whether metyrosine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Metyrosine should be given to a pregnant woman only if clearly needed.
What are the important warnings for Metyrosine?▼
WARNINGS Maintain Fluid Volume During and After Surgery When metyrosine is used preoperatively, alone or especially in combination with alphaadrenergic blocking drugs, adequate intravascular volume must be maintained intraoperatively (especially after tumor removal) and postoperatively to avoid hypotension and decreased perfusion of vital organs resulting from vasodilatation and expanded volume capacity. Following tumor removal, large volumes of plasma may be needed to maintain blood pressure and central venous pressure within the normal range. In addition, life-threatening arrhythmias may occur during anesthesia and surgery, and may require treatment with a beta-blocker or lidocaine. During surgery, patients should have continuous monitoring of blood pressure and electrocardiogram. CONTRAINDICATIONS Metyrosine capsules are contraindicated in persons known to be hypersensitive to this compound.
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Medical Disclaimer
This drug information is for educational purposes only and should not replace professional medical advice. Drug information is sourced from the FDA National Drug Code Directory and Structured Product Labeling. Always consult with a healthcare provider before starting, stopping, or changing any medication.