CYTADREN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CYTADREN (CYTADREN).
Aminoglutethimide inhibits the conversion of cholesterol to pregnenolone, thereby blocking adrenal steroidogenesis. It also inhibits aromatase, reducing estrogen synthesis.
| Metabolism | Hepatic metabolism via N-acetylation (polymorphic) and side-chain oxidation; metabolites are excreted renally. |
| Excretion | Renal: ~60% as unchanged drug; biliary/fecal: ~25% as metabolites; minor via respiration. |
| Half-life | Terminal elimination half-life: 3–4 hours in adults with normal renal function; prolonged to 8–12 hours in end-stage renal disease. |
| Protein binding | ~90% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd: 0.3–0.4 L/kg, indicating distribution primarily in extracellular fluid. |
| Bioavailability | Oral: 75–85% (first-pass metabolism ~20%). |
| Onset of Action | Oral: 30–60 minutes; intravenous: immediate (within 2 minutes). |
| Duration of Action | Oral: 6–8 hours; intravenous: 4–6 hours. Dose-dependent; effects monitored for hyperglycemia. |
200 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for GFR ≥30 mL/min. Not recommended for GFR <30 mL/min. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose to 100 mg once daily; Child-Pugh C: not recommended. |
| Pediatric use | Not approved for use in pediatric patients. |
| Geriatric use | No specific dose adjustment recommended; monitor renal function and volume status closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CYTADREN (CYTADREN).
| Breastfeeding | Aminoglutethimide is excreted into breast milk. M/P ratio not established. Contraindicated during breastfeeding due to potential for serious adverse effects in the infant, including adrenal suppression and hypothyroidism. |
| Teratogenic Risk | Cytadren (aminoglutethimide) is contraindicated in pregnancy. First trimester: High risk of teratogenicity including craniofacial defects. Second and third trimesters: Risk of fetal adrenal suppression, ambiguous genitalia in males, and other endocrine abnormalities. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to aminoglutethimide or glutethimide; pregnancy (teratogenic); lactation.
| Precautions | Adrenal insufficiency (may require glucocorticoid replacement), hypothyroidism, hepatotoxicity, rash (including Stevens-Johnson syndrome), blood dyscrasias (leukopenia, thrombocytopenia), neurologic effects (drowsiness, ataxia). |
| Food/Dietary | Avoid alcohol and foods high in tyramine (e.g., aged cheeses, cured meats, fermented products) if also taking MAOIs. Cyproheptadine may increase appetite, particularly for sweets; monitor caloric intake to prevent excessive weight gain. |
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| Fetal Monitoring |
| Maternal: Baseline and periodic liver function tests, thyroid function tests, complete blood count, and blood pressure monitoring. Fetal: If exposed (avoid in pregnancy), monitor for adrenal insufficiency, growth restriction, and ambiguous genitalia via ultrasound and neonatal assessment. |
| Fertility Effects | Aminoglutethimide may suppress ovarian function and interfere with ovulation, potentially reducing fertility. Reversible upon discontinuation. |
| Clinical Pearls |
| Cyproheptadine (Cytadren) is a first-generation antihistamine with potent antiserotonergic properties, making it useful for appetite stimulation and serotonin syndrome. Avoid in narrow-angle glaucoma, urinary retention, and concurrent MAOIs. Drowsiness is common; caution with driving. May cause significant weight gain with prolonged use. |
| Patient Advice | Take this medication exactly as prescribed, usually 2-4 mg three times daily. · Do not drive or operate heavy machinery until you know how this drug affects you, as it can cause drowsiness. · Avoid alcohol and other central nervous system depressants. · Notify your doctor if you experience blurred vision, difficulty urinating, or severe constipation. · Weight gain is possible; monitor your diet and activity level. · Store at room temperature away from moisture and heat. |