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.

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 ?
Competing interests: Afisi Ismaila, Amyn Sayani and Zhen Su are employees of GlaxoSmithKline (GSK), which markets and sells Avodart (dutasteride) and dutasteride-tamsulosin fixed combination therapy in Canada under the trade name Jalyn.
Glaxo representatives told panelists their data showed a favorable benefit in using Avodart in men who have high prostate-specific antigen (PSA) test results who have also undergone a biopsy that turned out to be negative.
In the GSK study, some men with moderate-to-severe symptoms were given the dual treatment CombAT, while others received just Avodart or Tamsulosin.
In the northern index, GlaxoSmith- Kline was again on the leader board following the successful trial of its cancer drug Avodart.
I've been on Flomax and Avodart for about five years, to no avail.
7bn from last year and slowing pharmauceutical sales, although there could be better news on growth drivers such as breast cancer drug Tykerb, obesity drug Alli and prostate treatment Avodart.
Although the combination provides greater dosing convenience that thought leaders believe may improve compliance among patients who require therapy to both alleviate symptoms and reduce prostate size, the many alternatives within the market--including generic dutasteride (GlaxoSmithKline's Avodart, Taiho Pharmaceutical's Avolve) as early as 2015--will contribute to constraining sales of tamsulosin/dutasteride in the United States, France, Germany, Italy, Spain, and the United Kingdom.
Avodart annual sales totaled $467 million based on recent IMS Health sales data.
This Lancet study showed there to be slightly fewer (14%) higher-grade tumors in the Avodart group compared to placebo (16%).
8] In a post-hoc analysis of the Combination of Avodart and Tamsulosin (CombAT) study in BPH patients, dutasteride, alone or in combination with tamsulosin, showed a relative reduction of 40% in the risk of detectable prostate cancers compared to tamsulosin monotherapy, as well as a 40% reduction in biopsies, over the 4-year study duration.
When evaluating males taking Avodart, Wright more often than not finds that their DHT may be low but their 3[beta]-adiol is even lower.
The combination of Avodart and Tamsulosin (CombAT) study is a 4-year multicentre study with additional entry threshold of PV (>30 mL) and PSA([greater than or equal to]1.