Avodart


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dutasteride

Avodart

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.

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) ,

Avodart

(trade name)

Classification

Therapeutic: benign prostatic hyperplasia bph agents
Pharmacologic: androgen inhibitors
Pregnancy Category: X

Indications

Management of the symptoms of benign prostatic hyperplasia (BPH) in men with an enlarged prostate gland (alone or with tamsulosin).

Action

Inhibits the enzyme 5-alpha-reductase, which is responsible for converting testosterone to its potent metabolite 5-alpha-dihydrotestosterone in the prostate gland and other tissues. 5-Alpha-dihydrotestosterone is partly responsible for prostatic hyperplasia.

Therapeutic effects

Reduced prostate size with associated decrease in urinary symptoms.

Pharmacokinetics

Absorption: Well absorbed (60%) following oral administration; also absorbed through skin.
Distribution: 11.5% of serum concentration partitions into semen.
Protein Binding: 99% bound to albumin; 96.6% bound to alpha-1 glycoprotein.
Metabolism and Excretion: Mostly metabolized by the liver via the CYP3A4 metabolic pathway; metabolites are excreted in feces.
Half-life: 5 wk.

Time/action profile (reduction in dihydrotestosterone levels†)

ROUTEONSETPEAKDURATION
POunknown1–2 wkunknown
†Symptoms may only improve over 3–12 mo

Contraindications/Precautions

Contraindicated in: Hypersensitivity;Cross-sensitivity with other 5-alpha-reductase inhibitors may occur;Women; Pediatric: Children.
Use Cautiously in: Hepatic impairment.

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

Oral (Adults) 0.5 mg once daily (with or without tamsulosin).

Availability (generic available)

Soft gelatin capsules: 0.5 mg
In combination with: tamsulosin (Jalyn); see combination drugs.

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.

Avodart

A brand name for DUTASTERIDE.
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References in periodicals archive ?
The Avodart franchise was down 7% AER, 5% CER to [pounds sterling]572 million, primarily due to the loss of exclusivity in Europe, with the US impact now broadly annualised.
Europe sales grew 1 % AER, but were flat at CER as growth from Tivicay and Triumeq was offset by continued generic competition to Epzicom and Avodart. Growth in the new Respiratory products offset the decline in Seretide.
Avodart Capsules may also be used with tamsulosin for the treatment of symptomatic benign prostatic hyperplasia in men with an enlarged prostate.
In Canada, the new marketed fixed-dose combination product, Jalyn (GlaxoSmithKline) (0.5 mg dutasteride + 0.4 mg tamsulosin) is the same price as dutasteride (Avodart, GlaxoSmithKline) alone, so that once the additional cost of tamsulosin is eliminated, the fixed-dose combination must be less expensive than the two drugs separately.
The two main classes of BPH drugs: alpha blockers like Flomax and UroXatral, which relax the muscles of the bladder neck and prostate, and 5-alpha reductase inhibitors like Proscar and Avodart, which lower levels of hormones produced by the prostate.
Clinical outcomes after combined therapy with dutasteride plus tamsulosin or either monotherapy in men with benign prostatic hyperplasia (BPH) by baseline characteristics:4-year results from the randomized, double blind Combination of Avodart and Tamsulosin (CombAT) trial.
If changing medications is not an option, your doctor may prescribe a drug to help control your symptoms, such as an alpha-blocker like Flomax or 5-alpha reductase inhibitor like Avodart, which are used to treat problems caused by prostate enlargement.
Of the 302 patients randomized, 38% of men given dutasteride (Avodart) 0.5 mg daily and 49% of those given placebo experienced some progression of their cancer.
The Oncologic Drugs Advisory Committee agreed, voting 17-0 to reject Merck's Proscar (finasteride) and 14-2 against Glaxo's Avodart (dutasteride).
A four-year study by GlaxoSmithKline (GSK) into a combined treatment using two drugs found results were better than using the individual drugs - Avodart or Tamsulosin -alone.
A four-year study by GlaxoSmithKline into a treatment using two drugs - CombAT - found results were better than using individual drugs - Avodart or Tamsulosin - alone.