Anti-depressant drug may affect fertility, says study

Antidepressant drugs taken by tens of thousands of British men may damage sperm quality and harm fertility, researchers at the Cornell Medical Centre in New York have found.

The doctors examined the effects of paroxetine (Seroxat) on men taking the drug over five weeks. Four weeks into the trial, tests revealed the men had sperm showing more than twice as much genetic damage as at the start of the study.

The findings remain tentative but pose a problem for GPs, who fear patients benefiting from anti-depressants may stop taking the drugs. NHS figures show that during 2006 GPs in Britain wrote nearly 2m prescriptions for paroxetine and the brand Seroxat.

The research team, led by Professor Peter Schlegel, showed that the amount of genetic fragmentation in sperm rose from an average of 13.8% before the trial to 30.3% after a month of the drug. The trial results will be presented in November at the American Society for Reproductive Medicine in San Francisco.

Steve Field, chairman of the Royal College of General Practitioners, said the results should not cause alarm: "Patients shouldn't stop their antidepressants, but those who are depressed and experiencing fertility difficulties may wish to discuss this with their GP."

Two years ago the same researchers reported that the antidepressants citalopram (Cipramil) and sertraline (Lustral) reduced sperm counts in men, although the counts returned to healthy levels after the medication was stopped.

According to New Scientist magazine, Schlegel believes some men who take paroxetine may have lower fertility because of it. Other scientists claim there is too little evidence to be sure. Allan Pacey, a lecturer in andrology at Sheffield University, said: "It's unclear what level of DNA damage causes a real problem for men."

Jane Morgan, a spokeswoman for GlaxoSmithKline, which markets Seroxat, said it would review the findings.