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Questions & Answers

Side Effects & Adverse Reactions

Maintain Fluid Volume During and After Surgery

When DEMSER is used preoperatively, alone or especially in combination with alpha-adrenergic 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.

Intraoperative Effects

While the preoperative use of DEMSER in patients with pheochromocytoma is thought to decrease intraoperative problems with blood pressure control, DEMSER does not eliminate the danger of hypertensive crises or arrhythmias during manipulation of the tumor, and the alpha-adrenergic blocking drug, phentolamine, may be needed.

Interaction with Alcohol

DEMSER may add to the sedative effects of alcohol and other CNS depressants, e.g., hypnotics, sedatives, and tranquilizers. (See PRECAUTIONS, Information for Patients and Drug Interactions.)

Legal Issues

There is currently no legal information available for this drug.

FDA Safety Alerts

There are currently no FDA safety alerts available for this drug.

Manufacturer Warnings

There is currently no manufacturer warning information available for this drug.

FDA Labeling Changes

There are currently no FDA labeling changes available for this drug.


DEMSER is indicated in the treatment of patients with pheochromocytoma for:

1. Preoperative preparation of patients for surgery

2. Management of patients when surgery is contraindicated

3. Chronic treatment of patients with malignant pheochromocytoma.

DEMSER is not recommended for the control of essential hypertension.


There is currently no drug history available for this drug.

Other Information

DEMSER1 (Metyrosine) is (–)-α-methyl-L-tyrosine or (α-MPT). It has the following structural formula:

Chemical Structure

Metyrosine is a white, crystalline compound of molecular weight 195. 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.

DEMSER is supplied as capsules, for oral administration. Each capsule contains 250 mg metyrosine. Inactive ingredients are colloidal silicon dioxide, gelatin, hydroxypropyl cellulose, magnesium stearate, titanium dioxide, and FD&C Blue 2.

Registered trademark of ATON PHARMA, INC.
All rights reserved

Demser Manufacturers

  • Aton Pharma, Inc.
    Demser (Metyrosine) Capsule [Aton Pharma, Inc.]

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