Dosing and uses of Demser (metyrosine)
Adult dosage forms and strengths
capsule
- 250mg
Chronic Pheochromocytoma
Indicated for treatment of patients with pheochromocytoma for: 1) preoperative preparation for surgery; 2) management when surgery is contraindicated; and 3) chronic treatment with malignant pheochromocytoma
Initial: 250 mg PO q6hr; may increase by 250-500 mg/day, not to exceed 4 g/day
Maintenance: Typically 2-3 g/day divided q6hr
Dosing Considerations
Not indicated for essential hypertension
When used for preoperative preparation, the optimally effective dose should be given for at least 5-7 days
Psychosis (Orphan)
Treatment of velocardiofacial syndrome associated psychosis
Orphan indication sponsor
- Aton Pharma, Inc; 3150 Brunswick Place; Lawrenceville, NJ 08648
Pediatric dosage forms and strengths
capsule
- 250mg
Chronic Pheochromocytoma
Indicated for treatment of patients with pheochromocytoma for: 1) preoperative preparation for surgery; 2) management when surgery is contraindicated; and 3) chronic treatment with malignant pheochromocytoma
<12 years: Safety and efficacy not established
≥12 years
- Initial: 250 mg PO q6hr; may increase by 250-500 mg/day, not to exceed 4 g/day
- Maintenance: Typically 2-3 g/day divided q6hr
Dosing Considerations
Not indicated for essential hypertension
When used for preoperative preparation, the optimally effective dose should be given for at least 5-7 days
Demser (metyrosine) adverse (side) effects
>10%
Sedation (>20%)
1-10%
Diarrhea (10%)
Exrapyramidal Symptoms (10%)
Frequency not defined
Fatigue
Headache
Psychic Disturbances
Galactorrhea
Sexual dysfunction
Nausea
Vomiting
Xerostomia
Nasal stuffiness
Dysuria
Crystalluria
Warnings
Contraindications
Hypersensitivity to metyrosine
Cautions
Additive sedative effects w/ alcohol and other CNS depressants
Take enough fluid to prevent crystalluria
Use caution in hepatic or renal impairment
Not recommended for essential HTn
Pregnancy and lactation
Pregnancy category: C
Lactation: not known if excreted into breast milk, use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Demser (metyrosine)
Mechanism of action
Inhibits synthesis of endogenous catecholamines by inhibiting tyrosine hydroxylase
Pharmacokinetics
Half-Life: 3-4 hr
Bioavailability: Well absorbed
Metabolism: liver
Metabolite: Catechol metabolites (inactive)
Excretion: urine 53-88%
