Avodart
dutasteride
Pharmacologic class: Synthetic 4-azasteroid compound
Therapeutic class: 5-alpha-reductase inhibitor, sex hormone
Pregnancy risk category X
Action
Inhibits 5-alpha-reductase, an intracellular enzyme present in liver, skin, and prostate that's required for conversion of testosterone to 5-alpha-dihydrotestosterone (DHT). DHT appears to be the principal androgen responsible for stimulating prostatic growth.
Availability
Capsules: 0.5 mg
Indications and dosages
➣ Symptomatic benign prostatic hypertrophy (alone or in combination with tamsulosin)
Adults: 0.5 mg P.O. daily
Contraindications
• Hypersensitivity to drug, its components, other 5-alpha-reductase inhibitors, xanthines (such as coffee, theobromine), or ethylenediamine
• Women
• Children
Precautions
Use cautiously in:
• hepatic impairment.
Administration
• Don't handle drug if you're pregnant or plan to become pregnant.
• Don't open or crush capsule.
• Give without regard to food.
Adverse reactions
GI: dyspepsia
GU: decreased libido, decreased ejaculatory volume, erectile dysfunction, gynecomastia
Interactions
Drug-drug. Cimetidine, ciprofloxacin, diltiazem, ketoconazole, other drugs metabolized by CYP450-3A4 pathway, ritonavir, verapamil: increased dutasteride blood level
Drug-diagnostic tests. Prostate-specific antigen (PSA): decreased level
Thyroid-stimulating hormone: increased level
Patient monitoring
• Monitor fluid intake and output. Assess for ease of starting urine stream and for urinary urgency or frequency.
• Check baseline PSA level; reevaluate at 3 to 6 months.
Patient teaching
• Tell patient to take drug with full glass of water without crushing or opening capsule.
• Instruct patient not to take capsule if it's cracked or leaking.
• Inform patient that drug decreases testosterone production in prostate.
• Tell patient to report dysuria and urinary urgency.
See Advise patient not to donate blood for at least 6 months after final dose.
• Inform patient that drug may decrease ejaculatory volume.
• Explain that sexual side effects eventually will subside.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs and tests mentioned above.
e
dutasteride
(doo-tas-te-ride) dutasteride,Avodart
(trade name)Classification
Therapeutic: benign prostatic hyperplasia bph agentsPharmacologic: androgen inhibitors
Indications
Action
Therapeutic effects
Pharmacokinetics
Time/action profile (reduction in dihydrotestosterone levels†)
| ROUTE | ONSET | PEAK | DURATION |
|---|---|---|---|
| PO | unknown | 1–2 wk | unknown |
Contraindications/Precautions
Adverse Reactions/Side Effects
Central nervous system
- depressed mood
Genitourinary
- prostate cancer (high-grade) (life-threatening)
- ↓ libido
- ejaculation disorders
- erectile dysfunction
- testicular pain
- testicular swelling
Endocrinologic
- gynecomastia
Dermatologic
- rash
- urticaria
Miscellaneous
- allergic reactions (life-threatening)
- angioedema (life-threatening)
Interactions
Drug-Drug interaction
Blood levels and effects may be ↑ by ritonavir, ketoconazole, verapamil, diltiazem, cimetidine, ciprofloxacin, or other CYP3A4 enzyme inhibitors.Route/Dosage
Availability (generic available)
Nursing implications
Nursing assessment
- Assess patient for symptoms of prostatic hyperplasia (urinary hesitancy, feeling of incomplete bladder emptying, interruption of urinary stream, impairment of size and force of urinary stream, terminal urinary dribbling, straining to start flow, dysuria, urgency) before and periodically during therapy.
- Digital rectal examinations should be performed before and periodically during therapy for BPH.
- Lab Test Considerations: Serum prostate-specific antigen (PSA) concentrations, used to screen for prostate cancer, decrease by about 20% within the 1st mo of therapy and stabilize at about 50% of the pretreatment level within 6 mo. New baseline PSA concentrations should be established at 3 and 6 mo of therapy and evaluated periodically during therapy. Any increase in PSA during dutaseride therapy may be a sign of prostate cancer and should be evaluated, even those within normal limits. Isolated PSA values from men taking dutaseride for 3 mo or more should be doubled for comparison in untreated men.
Potential Nursing Diagnoses
Impaired urinary elimination (Indications)Implementation
- Oral: Administer once daily with or without meals. Do not break, crush, or chew capsule.
Patient/Family Teaching
- Instruct patient to take dutasteride at the same time each day as directed, even if symptoms improve or are unchanged. Take missed doses as soon as remembered later in the day or omit dose. Do not make up by taking double doses the next day.
- Caution patient that sharing of dutasteride may be dangerous.
- Inform patient that the volume of ejaculate may be decreased during therapy but that this will not interfere with normal sexual function.
- Advise patient to avoid donating blood for at least 6 mo after last dose of dutasteride to prevent a pregnant female from receiving dutasteride through a blood transfusion.
- Inform patient of potential increase risk in high-grade prostate cancer.
- Caution patient that dutasteride poses a potential risk to a male fetus. Women who are pregnant or may become pregnant should avoid exposure to semen of a partner taking dutasteride and should not handle dutasteride because of the potential for absorption.
- Emphasize the importance of periodic follow-up exams to determine whether a clinical response has occurred.
Evaluation/Desired Outcomes
- Decrease in urinary symptoms of BPH.