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  Testosterone gel (Androgel)
 
Author: Donna Karasic, PharmD Last modified: March 31, 2002
 

  INDICATIONS

  • Male hypogonadism due to testicular failure or central hypogonadism
  • Hypogonadotrophic hypogonadism
  • Andropause (non-FDA approved use)

  DOSAGE

  • 5g (to deliver 50mg of testosterone) applied once daily (preferably in the morning) to clean dry intact skin of shoulders, upper arms, abdomen
  • Some clinicians dose 2.5 to 10g once daily based upon serum testosterone levels

  PHARMACOKINETICS

  • Approximately 10% of the applied testosterone dose is absorbed during a 24-hour period
  • Onset is 5 days; time to peak concentration is 4 hrs
  • Variable half-life of testosterone, from 10 to 100 minutes
  • Extensively metabolized by the liver
  • Testosterone is excreted in the urine as glucuronic and sulfuric acid conjugates of testosterone
  • Renal excretion is 90%; 6% excreted in the feces

  ADVERSE EFFECTS

  • Edema -rare
  • Hypertension -rare (<3%)
  • Gynecomastia (<3%)
  • Prostate disorders such as prostate cancer, enlargement of the prostate, BPH, elevated PSA
  • Increased LDL cholesterol and reduced HDL cholesterol
  • Increase in fat-free mass, muscle size, and strength in males
  • Priapism
  • Myocardial infarct
  • Mild but significant increases in mean WBC, RBC, hematocrit, and hemoglobin concentrations
  • Acne (2.8 to 12.5%)
  • Hair loss
  • Breast tenderness (1-3%)

  CONTRAINDICATIONS

  • Hypersensitivity to testpsterone
  • Males with breast carcinoma
  • Pregnancy
  • Do not use in patients with extensive cardiac, hepatic, renal disease, or carcinoma of the prostate

  DRUG INTERACTIONS

  • Oral anticoagulants
  • Cyclosporin
  • DHEA (dihydroepiandrosterone)
  • Dong quai (Angelica dahurica)
  • Corticosteroids, ACTH
  • Insulin

  FORMS

  • AndroGel 1%: Each packet contains 2.5g or 5g of gel to deliver 25mg or 50mg testosterone

  MECHANISM OF ACTION

  • Testosterone is an endogenous androgen and are responsible for normal growth and development of male sex organs
  • Testosterone is involved in the growth, maturation of prostate, seminal vesicles, penis, scrotum, development of male hair distribution,
  • also laryngeal enlargement, vocal cord thickening, alterations in body musculature and fat distribution
  • Testosterone increases protein anabolism and decrease protein catabolism
 
IMPORTANT POINTS/RECOMMENDATIONS
  • Use with caution in patients with increased risk of prostatic hypertrophy and prostatic carcinoma
  • Use with caution in patients with edema with or without congestive heart failure
  • Sleep apnea may be potentiated in obese patients or in those with chronic lung diseases
  • Apply 5gm (to deliver 50mg testosterone) once daily, preferably in the morning
  • Apply to clean, dry, intact skin of the shoulders, upper arms or abdomen
  • Allow skin to dry prior to dressing
  • Wash hands with soap and water after application
  • Delay showering or swimming by at least three hours
  • Follow serum testosterone levels every three to six months to ensure proper dosing
  • CBC should be monitored every three to six months and PSA levels yearly
 
REFERENCES
  1. Hutchinson TA & Shahan DR (Eds) ;  Testosterone ;  MICROMEDEX Healthcare Series; MICROMEDEX, Greenwood Village, Colorado (edition expires 3-2002)

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