CASODEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CASODEX (CASODEX).
Nonsteroidal antiandrogen that competitively inhibits the action of androgens by binding to cytosolic androgen receptors in target tissues, thereby blocking androgen-mediated gene expression and tumor growth. Does not suppress androgen production.
| Metabolism | Extensively metabolized in the liver via CYP3A4 to an active metabolite (hydroxybicalutamide) and inactive forms; undergoes glucuronidation. Major excretory route is biliary/feces, with minor renal elimination. |
| Excretion | Renal: <1% as unchanged drug; Fecal: ~83% as metabolites (mostly glucuronide conjugates); Biliary: significant as metabolites; Total clearance: 0.42 mL/min/kg |
| Half-life | Terminal elimination half-life: 5-7 days (steady-state achieved in ~4 weeks); Long half-life due to high protein binding and slow tissue redistribution |
| Protein binding | 96% bound to albumin and alpha-1-acid glycoprotein; Binding is saturable at high concentrations |
| Volume of Distribution | 0.3-0.5 L/kg (primarily bound in plasma; limited tissue distribution except prostate) |
| Bioavailability | Oral: ~80% (well absorbed; food does not affect significantly); No injectable form |
| Onset of Action | Oral: 2-4 weeks (initial clinical response); Maximal effect: 3-4 months |
| Duration of Action | Up to 4 weeks after discontinuation (due to slow elimination); Monitor PSA for sustained response |
| Action Class | Androgen receptor antagonist |
| Brand Substitutes | Ablu 50mg Tablet, Bical 50 Tablet, Castramid Tablet, Cosalon 50mg Tablet, Caluran 50 CP Tablet |
50 mg orally once daily
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for renal impairment; not studied in severe renal impairment (CrCl <30 mL/min), use with caution. |
| Liver impairment | Contraindicated in Child-Pugh Class C (severe hepatic impairment). For mild to moderate impairment (Child-Pugh A or B), no dose adjustment but monitor liver function. |
| Pediatric use | Safety and efficacy not established; no pediatric dosing available. |
| Geriatric use | No specific dose adjustment; elderly patients may be more sensitive to adverse effects (e.g., hot flashes, hepatic toxicity). Monitor renal and hepatic function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CASODEX (CASODEX).
| Breastfeeding | Unknown if excreted in human milk. Should not be used during breastfeeding. M/P ratio not available. |
| Teratogenic Risk | Contraindicated in pregnancy. Risk category X. Can cause fetal harm, including feminization of male fetuses due to antiandrogen activity. Avoid in pregnant women. |
| Fetal Monitoring | Monitor liver function tests, prothrombin time (PT/INR), and signs of hepatic injury. Monitor for fetal development if inadvertent exposure. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to bicalutamide or any component of the formulation; women who are or may become pregnant (risk of fetal harm); concomitant use with terfenadine, astemizole, cisapride, or pimozide (QT prolongation).
| Precautions | Hepatotoxicity (including hepatic failure; monitor liver function tests); pulmonary toxicity (interstitial pneumonitis); cardiovascular events (risk of myocardial infarction, QT prolongation); hypoglycemia in diabetic patients on sulfonylureas; gynecomastia and breast pain; reduced bone density; increased risk of fractures; potential for photosensitivity; not for use in women or pediatric patients. |
| Food/Dietary | No significant food interactions. Avoid grapefruit juice as it may alter drug metabolism. |
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| Fertility Effects | May impair spermatogenesis and reduce sperm count. Reversible after discontinuation. In males: gynecomastia, decreased libido, impotence. |
| Clinical Pearls | Monitor for hepatotoxicity; discontinue if jaundice or LFTs rise >3x ULN. Hot flashes and gynecomastia are common. Use with caution in patients with pre-existing hepatic impairment. No dose adjustment for renal impairment. |
| Patient Advice | Take with or without food. · May cause hot flashes, breast tenderness, or breast enlargement. · Report jaundice, dark urine, or upper right abdominal pain immediately. · Continue therapy even if feeling well; do not stop without consulting doctor. · Inform your doctor of all medications, including OTC and herbal supplements. · Use effective contraception during treatment and for 130 days after last dose. |