Home Drug Guide Metyrosine

Drug Guide

Generic Name

Metyrosine

Brand Names Demser

Classification

Therapeutic: Antihypertensive, Used in management of pheochromocytoma

Pharmacological: Tyrosine hydroxylase inhibitor

FDA Approved Indications

  • Pheochromocytoma (to control hypertension before surgery)

Mechanism of Action

Metyrosine inhibits tyrosine hydroxylase, the enzyme involved in catecholamine synthesis, reducing the production of dopamine, norepinephrine, and epinephrine.

Dosage and Administration

Adult: Initial dose: 250 mg four times daily; titrate as needed up to 2 g/day, divided into four doses.

Pediatric: Data limited; use with caution, typically reserved for life-threatening conditions under specialist supervision.

Geriatric: Start at lower end of dosing range due to increased sensitivity; monitor closely.

Renal Impairment: Adjust dose cautiously; no specific guidelines, use clinical judgment.

Hepatic Impairment: Use with caution; no specific guideline, monitor for adverse effects.

Pharmacokinetics

Absorption: Well absorbed orally.

Distribution: Widely distributed, crosses blood-brain barrier.

Metabolism: Partially metabolized in the liver.

Excretion: Excreted primarily via the urine.

Half Life: Approximately 2-4 hours.

Contraindications

  • History of hypersensitivity to metyrosine.
  • Severe hepatic impairment.

Precautions

  • Use with caution in patients with depression, as catecholamine depletion can exacerbate symptoms.
  • Monitor for extrapyramidal symptoms and neuropsychiatric effects.
  • Pregnancy: Data limited; potential risks vs benefit should be considered.

Adverse Reactions - Common

  • Sedation or fatigue (Common)
  • Gastrointestinal upset (nausea, vomiting) (Common)
  • Dizziness (Common)

Adverse Reactions - Serious

  • Neuropsychiatric effects (e.g., depression, hallucinations) (Less common)
  • Extrapyramidal symptoms (Uncommon)
  • Hematologic effects (e.g., leukopenia, agranulocytosis) (Rare)

Drug-Drug Interactions

  • Levodopa (may reduce efficacy)
  • Antipsychotics (potential interactions)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, neuropsychiatric status, and signs of adverse reactions.

Diagnoses:

  • Risk for ineffective tissue perfusion related to hypotension
  • Risk for injury related to sedation or orthostatic hypotension

Implementation: Administer with food to decrease GI upset, preferably at evenly spaced intervals.

Evaluation: Assess blood pressure response and monitor for adverse effects, neuropsychological status.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report any symptoms of depression, hallucinations, or unusual neuropsychiatric effects.
  • Monitor blood pressure regularly.
  • Be aware of potential sedative effects and avoid activities requiring alertness until response is known.

Special Considerations

Black Box Warnings:

  • No specific black box warnings.

Genetic Factors: N/A

Lab Test Interference: May cause falsely elevated levels of plasma catecholamines.

Overdose Management

Signs/Symptoms: Sedation, hypotension, extrapyramidal symptoms, depression.

Treatment: Supportive care, activated charcoal if ingestion is recent, symptomatic treatment, and monitoring.

Storage and Handling

Storage: Store at room temperature, away from light and moisture.

Stability: Stable under recommended storage conditions.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.