Commonly prescribed drugs for arthritis, depression and epilepsy have been linked to a range of potentially serious side effects including heart attacks, convulsions and birth defects.
The October bulletin of the federal government’s Adverse Drug Reactions Advisory Committee (ADRAC) contains warnings about the arthritis drugs Celebrex and Vioxx, the anti-depressant mirtazapine (marketed as Remeron, Avanza and Mirtazon) and anti-epilepsy drugs including Epilim and Valpro.
ADRAC warns of a possible increased risk of heart disease and cerebrovascular complications linked to Celebrex and Vioxx.
The committee says evidence of an association between Vioxx and cardiovascular events is inconclusive and indirect, and even weaker for Celebrex.
However, it says Vioxx should not be prescribed above the maximum approved dose and doctors should take into account cardiovascular risk before prescribing either drug.
Meanwhile, the committee said it had received 253 reports of adverse reactions to mirtazapine, for which there have been almost 500,000 funded prescriptions since it was listed on the PBS in May 2001.
The reactions included 16 reports of convulsions and 15 cases of potentially serious blood and bone marrow abnormalities.
Other adverse reactions included anxiety, nightmares, vomiting, liver problems and hallucinations.
In relation to anti-epileptic drugs (AEDs), the committee said doctors should be aware of the potential for birth defects when the drugs were taken by pregnant women.
“Prescribers should review the medication of women on AEDs in pre-pregnancy planning,” the bulletin recommends.
ADRAC said analysis of 40-month data from the Australian Pregnancy Register for Women on Anti-epileptic Medication showed 6.5 per cent of 403 women taking an AED delivered a baby with a birth defect.
Eighty-eight per cent had a healthy live birth and the remainder had spontaneous abortions or death in the womb.
The rate of defects was significantly higher in women exposed to valproate (marketed as Epilim and Valpro) in the first trimester than those exposed to other AEDs, ADRAC said.
The dose of valproate was significantly higher in those with foetal malformations, the bulletin noted.
ADRAC also noted that a recently published Finnish study of 970 babies found an association between AEDs and birth defects.