DRUGS & CHEMICALS AND INFERTILITY

What drugs and other substances affect sperm production?

There are a number of commonly used drugs, which may have a negative effect on sperm production and function.

• Drugs used in the treatment of cancer
  are designed to attack the growing cells of the cancer but can also have an effect on other cells that are growing.  The cells in the lining of the sperm-producing tubes in the testis are continually growing to produce the new cells needed to make sperm.  These cells are therefore open to attack during cancer treatment.  Cyclophosphamide, a drug used for the treatment of some cancers and kidney disorders, can cause permanent infertility if the treatment is given for a long period of time.
   
• Salazopyrine
  which is used to treat inflammatory bowel disease, causes temporary infertility.  This drug is often given for ulcerative colitis, Crohn’s disease, or problems occurring following other conditions such as rheumatoid arthritis.  These diseases can often be managed with other medications, which allow the man to remain fertile.  When salazopyrine is stopped, sperm production will usually return to normal after a few months.
   
• Environmental and chemical agents
  such as pesticides, may cause infertility.  However, there is no clear proof of the extent that these chemicals cause sperm production problems. There is much debate about the possible long-term effects of pesticides and other industrial agents, such as some heavy metals and glycol ethers, on male fertility. However, since it may take some 25 years for an early exposure to such agents to be identified in adulthood as an infertility disorder, common sense points to the need for further research and the use of caution in the widespread use of such agents. 
   
• Testosterone (tablets or injections)
  which are used to treat men with testosterone deficiency, can cause infertility problems.  These drugs stop the production of pituitary hormones (FSH and LH), which normally stimulate the testes.  This reduces the size of the testes and can lower or stop sperm production.  Men who inappropriately use testosterone and more potent androgens for body building and competitive sports, can not only become infertile, but also place other aspects of their health at risk.
   
• Recreational drugs
  such as marijuana, may affect the testes and affect the long-term production of sperm in the testes.

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Can anything be done before starting drug treatment?

Chemotherapy for treatment of cancer can lower sperm counts temporarily or permanently.

All men, and boys advanced through puberty, about to have cancer treatment should get advice from their doctors about the effect of their treatment on their fertility.  It is highly recommended that men produce semen samples (through masturbation) for sperm banking.  Sperm storage must take place before treatment starts.  Semen can be frozen and stored long-term for future use.  If men want children at a later stage, the frozen semen is thawed and used in fertility treatments such as in vitro fertilisation (IVF). 

More information: Assisted Reproductive Technologies

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How is infertility caused by drugs or chemicals treated?

Some drugs can leave men permanently sterile and there are no treatment options available to restore sperm production.  Other drugs only have a temporary effect on sperm production.  Once these drugs are stopped, sperm production should return.  However, because of the long time it takes for sperm to develop, it may take between six and 12 months for sperm counts to reach normal levels.

To avoid pregnancy problems and possible foetal abnormalities, doctors sometimes recommend that couples wait for six to 12 months before trying to become pregnant after certain drugs have been taken.

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Storage of sperm before medical treatment

Sperm can be medically stored for use at a later date by keeping them at very low temperatures while still maintaining a reasonable sperm quality. Sperm storage is particularly important if a man is to undergo a medical treatment that affects sperm production. This can include the effects of  chemotherapy or radiation damage for the treatment of cancer, or the use of drugs and other substances causing infertility, such as salazopyrine.

Specialist reproductive centres providing assisted reproductive technologies usually also offer long-term sperm storage facilities. For more information about long-term sperm storage, contact your nearest IVF clinic or speak to your specialist.

Download: Male Infertility fact sheet PDF (61kb)

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