A popular anti-depressant has been linked with growing numbers of suicides and accidental overdoses, statistics show.
Rise in venlafaxine-related deaths
Between 1993 and 2002, 118 people in England and Wales taking venlafaxine (Efexor) died - 17.6 deaths per million prescriptions.
Although the rate is still lower than that associated with old-generation tricyclic drugs, it is rising, while the rate for tricyclics is falling.
The figures were collected by the National Audit Office.
Overall, there were 4,767 antidepressant-related deaths in England and Wales in the decade studied.
Nearly eight out of every 10 of these were suicides.
Tricyclic antidepressants made up the bulk of the cases, linked to nearly 4,000 deaths, or 43.1 deaths for every million prescriptions.
But venlafaxine, from the selective noradrenaline reuptake inhibitor (SNRI) drug family, overtook another class of newer antidepressants that includes drugs like Prozac (fluoxetine) and Seroxat (paroxetine) - the selective serotonin reuptake inhibitors (SSRIs).
SSRIs were linked to 310 deaths overall, but the rate was only 4.3 deaths per million prescriptions.
Since it was launched in 1995, prescriptions of venlafaxine have reached 3.2 million over the last 12 months, earning the manufacturer Wyeth £125 million per year.
A spokeswoman from Wyeth said the statistics did not compare like with like.
"They do not take into account the severity of the condition of people being treated, or the fact that patients being given Efexor have often failed on other antidepressants.
"The patients are often more seriously ill with depression and that is why the figures are higher," she said.
Sophie Corlett, director of policy at Mind said because Efexor was a relatively new antidepressant, reports of adverse side effects had only begun to emerge recently.
"Mind has been aware for some time of reports from mental health service users of quite debilitating side effects ranging from dizziness and nausea to severe headaches and dependency problems.
"Although, on the whole, Efexor has a better reputation than other antidepressants, in a recent survey almost half of respondents reported difficulties when coming off the drug or in reducing its dose.
She said questions remained over the links between certain antidepressants and possible increased suicidal feelings.
"It is therefore vital both that alternative non-drug therapies are explored for less serious cases of depression and that where drug treatment is the only realistic option, that those drugs are rigorously tested and regulated."
But she added: "Anyone taking antidepressants who has concerns should consult their doctor. On no account should they simply stop taking the medicine."
A spokeswoman from the Department of Health said the Committee on Safety of Medicines and its expert working group on SSRIs was reviewing the data relating to the safety and efficacy of venlafaxine as part of its ongoing work.
"SSRIs are known to be safer in overdose than the older tricyclic class of antidepressants," she said.
The National Institute for Clinical Excellence is also soon due to produce guidelines on the treatment of depression and anxiety in adults in October of this year.