We're unable to sign you in at this time. Please try again in a few minutes.
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......

Ketoconazole Blocks Testosterone Synthesis

Allan Pont, MD; Paul L. Williams, MD; Salman Azhar, PhD; Richard E. Reitz, MD; Charlotte Bochra; Erla R. Smith, PhD; David A. Stevens, MD
Arch Intern Med. 1982;142(12):2137-2140. doi:10.1001/archinte.1982.00340250097015.
Text Size: A A A
Published online


• Ketoconazole, a new oral drug used to treat systemic and superficial mycoses, inhibits sterol synthesis in fungi. The development of gynecomastia in two patients prompted us to investigate the effect of the drug on testosterone production. After a 200-, 400-, or 600-mg dose, volunteer male testosterone serum concentrations fell markedly, but returned toward baseline eight to 24 hours later as ketoconazole serum concentrations waned. A marked but transient drop in testosterone levels occurred in patients receiving long-term therapy, and continuous testosterone depression was noted in one. A block of synthesis was demonstrated in vitro. Ketoconazole at concentrations achievable in serum with currently used doses blocked basal and gonadotropin-stimulated testosterone production by rat Leydig cells. The diminution of testosterone synthesis could be significant as further therapeutic trials may use larger doses or more than once-daily administration. The paucity of reports of endocrinologic toxicity may relate to the "escape" from the block demonstrated in vivo.

(Arch Intern Med 1982;142:2137-2140)


Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?





Also Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
Please click the checkbox indicating that you have read the full article in order to submit your answers.
Your answers have been saved for later.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.


Some tools below are only available to our subscribers or users with an online account.

0 Citations

Sign in

Purchase Options

• Buy this article
• Subscribe to the journal
• Rent this article ?

Related Content

Customize your page view by dragging & repositioning the boxes below.