DUTASTERIDE
Clinical safety rating
avoidContraindicated (not allowed)
Competitive inhibitor of type II and type I 5α-reductase isoenzymes, blocking conversion of testosterone to dihydrotestosterone (DHT) in prostate, hair follicles, and other tissues.
| Metabolism | Extensively metabolized in liver via CYP3A4 and CYP1A2; minor metabolism by CYP2C8, CYP2C9, CYP2C19, and CYP2D6. |
| Excretion | Primarily fecal (70%) as metabolites; renal excretion accounts for <5% unchanged drug. |
| Half-life | Terminal half-life approximately 3-4 weeks (21-35 days) in young adults; 5-6 weeks in elderly; supports once-daily dosing due to slow elimination. |
| Protein binding | >99% bound to albumin and alpha-1 acid glycoprotein; high affinity. |
| Volume of Distribution | Approximately 300-500 L (3-5 L/kg), indicating extensive tissue distribution, particularly to prostate and seminal vesicles. |
| Bioavailability | Oral: Approximately 60% (range 40-80%) with food; not administered parenterally. |
| Onset of Action | Oral: Clinical effect (reduction in serum DHT) observed within 1 week; maximal effect on prostate volume at 6-12 months. |
| Duration of Action | Prolonged due to slow elimination; effect persists for 6-12 months after discontinuation due to tissue binding. |
| Molecular Weight | 528.53 |
0.5 mg orally once daily.
| Dosage form | CAPSULE |
| Renal impairment | No dose adjustment required for renal impairment (including dialysis). |
| Liver impairment | Contraindicated in Child-Pugh Class C; use with caution in mild to moderate impairment (Child-Pugh A/B) with no specific dose adjustment established. |
| Pediatric use | Not indicated in pediatric patients; safety and efficacy not established. |
| Geriatric use | No specific dose adjustment required; monitor for adverse effects (e.g., dizziness, orthostatic hypotension) due to age-related comorbidities. |
| 1st trimester | Contraindicated due to risk of feminization of male fetus; Dutasteride inhibits dihydrotestosterone conversion, critical for male sexual development. |
| 2nd trimester | Contraindicated; similar risks as first trimester. |
| 3rd trimester | Contraindicated; similar risks as first trimester. |
Clinical note
Strong CYP3A4 inhibitors may increase levels Pregnant women should not handle crushed capsules due to risk of fetal abnormality.
| Placental transfer | Crosses placenta in animal studies; likely crosses human placenta based on molecular weight and lipophilicity. |
| Breastfeeding | Excreted into breast milk in animal studies; unknown in humans. Use during breastfeeding only if clearly needed and with caution. |
| Lactation Rating | L3 (Moderately Safe) - limited data; potential for adverse effects in nursing infant. |
| Teratogenic Risk | Dutasteride is contraindicated in pregnancy. It is a 5α-reductase inhibitor that can inhibit the conversion of testosterone to dihydrotestosterone (DHT), potentially causing abnormal development of external genitalia in male fetuses. Risk extends throughout all trimesters due to potential disruption of androgen-mediated development in male fetuses during the first trimester and cumulative effects from drug accumulation in adipose tissue. No adequate human studies exist; animal studies show teratogenicity in male offspring at clinically relevant doses. |
| Fetal Monitoring | If exposure occurs, assess pregnancy status. Monitor fetal development via ultrasound for potential genital anomalies in male fetuses. No specific maternal monitoring required; routine prenatal care. Dutasteride is not indicated for women; any inadvertent exposure warrants pregnancy counseling and follow-up. |
| Fertility Effects | Dutasteride may decrease sperm count, semen volume, and sperm motility, potentially impairing male fertility. Effects are reversible upon discontinuation. No direct female fertility data; as a 5α-reductase inhibitor, it could theoretically affect ovarian function, but evidence is lacking. Treatment of male partners with dutasteride does not appear to harm female fertility or pregnancy outcomes from limited studies. |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | Impotence Decreased libido Ejaculation disorder Orthostatic hypotension sudden lowering of blood pressure on standing Breast enlargement in male Breast tenderness in male |
| Serious Effects |
PregnancyWomen of childbearing potentialHypersensitivity to dutasteride or other 5-alpha-reductase inhibitors
| Precautions | Risk of high-grade prostate cancer in men aged 50-79 with elevated PSA and previous negative biopsy (see PLCO trial), Increased risk of sexual adverse events (impotence, decreased libido, ejaculation disorders) that may persist after discontinuation, Elevated PSA levels: use caution when interpreting PSA values; establish new baseline after 6 months of treatment |
| Food/Dietary | No clinically significant food interactions. May be taken with or without food. Grapefruit juice does not affect dutasteride levels to a clinically relevant extent. |
| Clinical Pearls | Monitor PSA levels cautiously, as dutasteride reduces serum PSA by approximately 50% after 6 months; double the PSA value for comparison to untreated men. Do not handle crushed or broken capsules if pregnant or planning pregnancy, as absorption through skin may cause fetal harm. Assess for signs of high-grade prostate cancer before initiating therapy, as dutasteride may increase the risk of Gleason 8-10 tumors. Onset of symptom relief may take 3-6 months; do not discontinue prematurely. Avoid concomitant use with strong CYP3A4 inhibitors (e.g., ritonavir, ketoconazole) as they increase dutasteride exposure. |
| Patient Advice | Take exactly as prescribed; do not stop or change dose without consulting your doctor. · Swallow the capsule whole; do not chew or open it. · It may take 3 to 6 months to see improvement in symptoms. · Avoid handling leaking or crushed capsules if you are a woman who is or may become pregnant; wash area immediately with soap and water if skin contact occurs. · Do not donate blood for at least 6 months after your last dose to prevent exposure to a pregnant woman. · Report any breast lumps, pain, or nipple discharge promptly. · You will need regular blood tests for PSA level monitoring; inform your doctor that you are taking dutasteride. · Dutasteride can decrease sperm count and may affect fertility; discuss this with your doctor if planning to father a child. |
Loading safety data…