Medications designed to treat symptoms and cure disease can also cause unanticipated problems with the male reproductive system. Exposures to drugs can be accidental through in utero exposure during fetal development. Use of illegal drugs or anabolic steroids can also have deleterious effects on the male reproductive system.
Drugs that can cause problems with sperm quantity or quality include antibiotics such as nitrofurantoin, erythromycin, cyclosporine, gentamycin and tetracycline. Cimetidine whose brand name is Tagamet and is prescribed to treat stomach cancers and the anti-epileptic drug Dilantin have both been implicated in reducing male fertility. Cardiac medications like antihypertensives may also cause problems with sperm quality.
Anabolic steroids, particular testosterone, act as part of a negative-feedback-system between the testicles and the brain. High levels of anabolic steroids shut off the brain's signal to the testicles to make more testosterone.
Chemotherapy can cause sperm production to stop. Prior to chemotherapy, men are encouraged to bank sperm because they man not recover their ability to make sperm. Many cancer survivors will recover some ability to produce sperm after a period of months of years, but sperm count may be low. Because chemotherapy may induce genetic mutations in sperm, men are counseled to wait a minimum of two years after completing chemotherapy before attempting to father a child.
Social drugs like alcohol, tobacco and even too much caffeine can cause male infertility. Street drugs like marijuana, heroin and methadone used to treat heroin addiction can decrease sperm quantity or quality, negatively affecting fertility.
Many drugs have the potential to cause erectile dysfunction. Drugs to control high blood pressure such as clonidine, thiazides, spironolactone and beta blockers may cause erectile dysfunction. Drugs that affect the central nervous system such as monoamine oxidase inhibitors, selective serotonin reuptake inhibitors, tricyclics, anxiolytics, alcohol, opioids and cocaine may also cause erectile dysfunction according to the Merck Manual.
Other prescribed drugs such as anticholinergics, estrogens, chemotherapy drugs, amphetamines, anti-androgens and drugs that mimic gonadotropin releasing hormone can cause erectile dysfunction.
Hypogonadism refers to an underproduction of male hormone, mainly testosterone, by the testis. Normal levels of testosterone are necessary for normal fetal development of the male reproductive system and for normal masculine changes associated with puberty. After puberty, normal testosterone levels are required to maintain sperm production and normal sexual function.
According to MayClinic.com, hypogonadism can be caused by chemotherapy drugs, opiates and some hormones. Anabolic steroids such as testosterone used to pump up muscle mass have the opposite effect on testicular function, causing testicles to shrink and hormone production to crash.
Reproductive System Development
Drugs a pregnant woman takes can affect the development of the male reproductive system in uterus. Women who took a synthetic estrogen called DES between the late 1940s and early 1970s to prevent pregnancy loss were more likely to have sons with reproductive system defects according to a Guttmacher Institute report. The fetal exposure to synthetic estrogen caused structural malformations of the male reproductive tract and decreased semen quality. The use of DES for pregnant women has been banned.