Benign prostatic hyperplasia (alternative agent): Note: Reserve use for patients with significantly enlarged prostates (prostate volume >30 mL, prostate-specific antigen >1.5 ng/dL, or palpable prostate enlargement on digital rectal exam) or those with hematuria associated with benign prostatic hyperplasia (AUA [Lerner 2021a]; AUA [Lerner 2021b]; McVary 2022).
Oral: 0.5 mg once daily alone or in combination with an alpha-1 adrenergic antagonist (AUA [Lerner 2021a]; manufacturer's labeling).
No dosage adjustment is necessary.
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied). Dutasteride is extensively hepatically metabolized and exposure could be increased in hepatic impairment, however, higher doses studied did not generally produce additional adverse effects.
Refer to adult dosing.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Avodart: 0.5 mg [contains gelatin (bovine)]
Generic: 0.5 mg
Yes
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Avodart: 0.5 mg
Generic: 0.5 mg
Oral: May be administered without regard to meals. Capsule should be swallowed whole; do not chew or open; contact with opened capsule can cause oropharyngeal irritation. Should not be touched or handled by patients who are or who may be pregnant.
Hazardous agent (NIOSH 2016 [group 3]).
Use appropriate precautions for receiving, handling, administration, and disposal. Gloves (single) should be worn during receiving, unpacking, and placing in storage. NIOSH recommends single gloving for administration of intact tablets or capsules (NIOSH 2016). Assess risk to determine appropriate containment strategy (USP-NF 2017).
Benign prostatic hyperplasia: Treatment of symptomatic benign prostatic hyperplasia (BPH) as monotherapy (to improve symptoms, reduce the risk of acute urinary retention, and to reduce the risk of need for BPH-related surgery) or combination therapy with an alpha-1 adrenergic antagonist to reduce the risk of symptomatic progression (AUA [Lerner 2021a]; manufacturer's labeling).
Male pattern baldness
The Institute for Safe Medication Practices (ISMP) includes this medication among its list of drugs that have a heightened risk of causing significant patient harm when used in error.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
Frequency of most adverse events (except prostate cancer high grade) tends to decrease with continued use (>6 months). Frequency not always defined.
1% to 10%:
Endocrine & metabolic: Decreased libido (≤3%; incidence highest during first 6 months of therapy), gynecomastia (including breast tenderness, breast enlargement; ≤1%), increased luteinizing hormone, increased testosterone level, increased thyroid stimulating hormone level
Genitourinary: Impotence (≤5%; incidence highest during first 6 months of therapy), ejaculatory disorder (≤2%)
Hematologic & oncologic: Prostate cancer high grade (≤1%)
<1%, postmarketing, and/or case reports: Angioedema, cardiac failure, depressed mood, dermatological reaction (serious), dizziness, hypersensitivity, localized edema, malignant neoplasm of breast (males), pruritus, skin rash, testicular pain, testicular swelling, urticaria
Clinically significant hypersensitivity to dutasteride, other 5-alpha-reductase inhibitors (eg, finasteride), or any component of the formulation; pregnancy.
Disease-related concerns:
• Diminished urinary flow: Carefully monitor patients with a large residual urinary volume or severely diminished urinary flow for obstructive uropathy; these patients may not be candidates for dutasteride therapy.
• Hepatic impairment: Use with caution in patients with hepatic impairment.
• Prostate cancer: When compared to placebo, 5-alpha-reductase inhibitors (5-ARIs) have been shown to reduce the overall incidence of prostate cancer, although an increase in the incidence of high-grade prostate cancers has been observed; 5-ARIs are not approved in the United States or Canada for the prevention of prostate cancer.
Concurrent drug therapy issues:
• CYP3A4 inhibitors: Use with caution with concurrent use of potent, chronic CYP3A4 inhibitors.
Other warnings/precautions:
• Appropriate use: Other urological diseases, including prostate cancer, should be ruled out before initiating therapy.
• Blood donation: Avoid donating blood during or for 6 months following treatment cessation due to risk of administration to a transfusion recipient who is pregnant.
• PSA monitoring: Reduces prostate specific antigen (PSA) by ~50% within 3 to 6 months of use. If following serial PSAs, re-establish a new baseline ≥3 months after treatment initiation; monitor PSA periodically thereafter. If interpreting an isolated PSA value in a patient treated for ≥3 months, then double the PSA value for comparison. PSA increases while on dutasteride should be considered suspicious; obtain serial PSA measurements and evaluate (Andriole 2006). Patients on a 5-ARI with any increase in PSA levels, even if within normal limits, should be evaluated; may indicate presence of prostate cancer.
Substrate of CYP3A4 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential
CYP3A4 Inhibitors (Strong): May increase the serum concentration of Dutasteride. Risk C: Monitor therapy
Maximum serum concentrations reduced by 10% to 15% when taken with food; not clinically significant. Management: Administer without regard to meals.
Dutasteride can be detected in semen; sperm count, semen volume, and sperm movement may be decreased, but the effect on male fertility is unknown.
Based on the mechanism of action and data from animal reproduction studies, in utero exposure to dutasteride may cause fetal harm. Use is contraindicated during pregnancy.
Capsules should not be handled by patients who are or who may be pregnant; if contact with a leaking capsule occurs, wash area immediately with soap and water.
It is not known if dutasteride is present in breast milk.
To interpret serial prostate-specific antigens (PSAs), establish a new PSA baseline ≥6 months after treatment initiation and monitor PSA periodically thereafter. International Prostate Symptom Score (baseline and 3 to 12 months after treatment initiation); urinalysis (baseline); objective and subjective signs of relief of benign prostatic hyperplasia and lower urinary tract symptoms (AUA [Lerner 2021a]; McVary 2022; manufacturer's labeling).
Dutasteride is a 4-azo analog of testosterone and is a competitive, selective inhibitor of both reproductive tissues (type 2) and skin and hepatic (type 1) 5α-reductase. This results in inhibition of the conversion of testosterone to dihydrotestosterone and markedly suppresses serum dihydrotestosterone levels.
Absorption: Absorbed via skin when handling capsules
Distribution: Vd: 300 to 500 L, ~12% of serum concentrations partitioned into semen
Protein binding: 99% to albumin; ~97% to alpha1-acid glycoprotein; >96% to semen protein
Metabolism: Hepatic via CYP3A4 and CYP3A5 isoenzymes (extensive); forms metabolites: 6-hydroxydutasteride has activity similar to parent compound, 4′-hydroxydutasteride and 1,2-dihydrodutasteride are much less potent than parent in vitro
Bioavailability: ~60% (range: 40% to 94%)
Half-life elimination: Terminal: ~5 weeks
Time to peak: 2-3 hours
Excretion: Feces (40% as metabolites, ~5% as unchanged drug); urine (<1% as unchanged drug); ~55% of dose unaccounted for
Geriatric: Dutasteride half-life increases with age.
Capsules (Avodart Oral)
0.5 mg (per each): $9.49
Capsules (Dutasteride Oral)
0.5 mg (per each): $1.67 - $6.05
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.