Drugs Compromising Male Sexual Health Walter Krause

Walter Krause Drugs Compromising Male Sexual Health Walter Krause Drugs Compromising Male Sexual Health 123 Walter Krause, Em. Prof. Dr. med. Universitätsklinikum Gießen und Marburg Klinik für Dermatologie und Allergologie 35033 Marburg Germany Library of Congress Control Number: 2007935896 ISBN 978-3-540-69859-3 Springer Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprin- ting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. 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Editor: Marion Philipp, Heidelberg, Germany Desk Editor: Ellen Blasig, Heidelberg, Germany Reproduction, typesetting and production: LE-TEX Jelonek, Schmidt & Vöckler GbR, Leipzig, Germany Cover design: Frido Steinen-Broo, EStudio, Calamar, Spain SPIN 11932864 Printed on acid-free paper 24/3180/YL 5 4 3 2 1 0 Foreword V Foreword Testosterone is my favourite hormone, a focus of my research. In the public mind it is the body’s most potent chemical, making the difference between a 90-pound weakling and a he-man, between a milquetoast and a lothario. Steroid analogues, stacked by muscle builders, are supposed to cause out-of-control “’roid rages”. Some people be- lieve an injection of testosterone propelled Floyd Landis from also-ran to his “miracu- lous Stage 17” of the Tour de France. The hormone has become part of the language of popular culture. The New York Times carried the following passages in the previous 2 weeks: “I always thought downtown had a high testosterone level”, referring to the high male- to-female ratio of residents in lower Manhattan (14 April 2007). “It is the kind of gathering that, at its most primal, has testosterone flowing more freely than the on-the-house spirits”, referring to a news conference prior to a boxing match (20 April 2007). “[T]hese are testosterone-fueled domains, largely defined by bulging muscles and ex- ploding guns”, in a review of an action movie (20 April 2007). “[T]his film is about [auto racing] surfaces, for young men with testosterone to burn”, from a review of another action movie (14 April 2007). For decades, testosterone has been proposed as a pharmaceutical fountain of youth, presumably capable of rebuilding aging muscle, restoring strength and vigor, bolster- ing masculine assertiveness, and resuscitating libido and penetrating power. For nearly as long, testosterone has been suspected of adverse side effects, particularly on the prostate. Recent reassessment of hormone replacement therapy for postmenopausal women may have muted calls for male hormone replacement. Still, that popular image of testosterone is “tempting stuff” to men in decline. Homer tells us that Achilles was given a choice of dying young as a famous hero, or living a long and happy, but otherwise ordinary, life. It was a difficult decision. Achilles vacillated, but after the death of Petroclus he opted for swift glory. Today, for an aging male, the Achillean choice might be framed as 10 years of vigorous life (on testosterone replacement), or 20 years of continuing dilapidation. This seems to me an easier choice: I would opt for 10 strong years. Medically sophisticated readers know that the options are not so clear-cut. As Wal- ter Krause points out, supplementing testosterone (beyond a low threshold level) does not measurably improve a man’s sexual functioning, which wanes with age anyway. I would add that exogenous testosterone does improve muscle mass, but its other claimed benefits are not reliably sustained in the research literature. The popular im- pression of its Herculean effects on male psyches and athletic prowess, promoted by our mass media, is almost certainly as mythical as Hercules. On the other hand, generally deleterious effects on the prostate are not confirmed either. VI Foreword There is really no Achillean choice between one decade of vigor and two of se- nescence. Medicine offers lesser trade-offs: some alleviation of ills at the cost of some side effects. Professor Krause shows us when the side effects do, or do not, include compromising “that most male of activities”. For example, specific serotonin reuptake inhibitors (SSRIs), while relieving depression, promote erectile and orgasmic dysfunction. Sometimes side effects can be turned to advantage. The SSRIs are useful in treat- ing premature ejaculation. Occasionally the trade-off is too good to pass up. Phosphodiesterase inhibitors, most famously Viagra, restore potency with adverse effects that are generally mild and self-limiting. Initial fears of increased risk of heart attack, provoking all those jokes about dying happy, are not sustained. Professor Krause’s database shows no general cardiac side effects in most studies, and no increase in myocardial infarction (excepting men taking nitrate medications). In overview, the first part of this book is short and will be read with profit by anyone inclined to open the volume in the first place. It contains concise, up-to-date descrip- tions of testicular function, erection and ejaculation. The second, bulky part of this book − the database of drugs − is not a page turner, but readers will be rewarded by digesting selected portions. In exhaustively catalogu- ing and summarizing the literature on adverse drug effects on male sexual health, and evaluating the quality of each study, Professor Krause gives the best demonstration I have seen of inconsistency among research reports − some deserving trust, others not. This may not be big news to experienced researchers, but I suspect it will surprise many clinicians. (I wish science and health journalists would spend some time in the database, because it might help them realize that novel findings reported in the press and on television are often irreproducible.) Readers must turn elsewhere for discussions of bias and fraud in medical research. Here, even stipulating the honesty and objectivity of researchers, one can only wonder how some of their work made it into print. In any sensible overview of the research literature, it is essential to consider the quality of each report, as Professor Krause has done. It will be a long time before this volume is replaced by a better source on drugs that affect male sexual function. Allan Mazur Professor of Public Affairs The Maxwell School Syracuse University Syracuse, NY Preface VII Preface Adverse effects of drugs on sexual functions are often neglected in practical medicine, because they are usually mild or moderate and rarely prompt hospital admissions, de- nominated as severe ADEs. In addition, standard textbooks of pharmacology and those which discuss drug side effects consider these topics only marginally, and well-known sexual side effects are not mentioned. There are, of course, a number of review articles on the possible adverse effects of drugs on sexual dysfunction, in particular on erectile dysfunction. But delineations of the exact figures of the incidence of sexual adverse effects in a concrete drug are often lacking in these papers. Reviews also frequently do not describe the database of the reported adverse effects, thus leaving the quality of evidence uncertain. This book summarizes quotations from the literature which describe particular effects of drugs on male sexual functions. A special concern of the composition is the information on the quality rating of the reports quoted, and to reflect the overall quality of evidence that supports a specific adverse effect of a pharmacological or therapeutic subgroup of drugs. The quality rating is expressed in analogy to the grading system for clinical studies of the Scottish Intercollegiate Guidelines Network (SIGN). The system- atic of drugs follows the ATC/DDD system published by the WHO. The book is intended to encourage physicians who use any of the drugs mentioned for treatment in their patients to ask their patients about adverse effects, and to give attention to possible observations in their patients. A collection of these observations will enhance our knowledge of the compromising of male sexual health by drugs. Marburg, October 2007 Walter Krause Contents IX Contents 1 Male Sexual Health .................................... 1 1.1 Structure and Physiology of the Testis ................... 3 1.1.1 Introduction ............................................ 3 1.1.2 The Spermatozoa ....................................... 6 1.1.3 Sperm Motility .......................................... 8 1.1.4 Capacitation and Acrosome Reaction ................... 10 1.1.5 Fertilization of the Oocyte .............................

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