HL Deb 25 May 1999 vol 601 cc85-6WA
Baroness Gould of Potternewton

asked Her Majesty's Government:

What assessment they have made of possible interactions between contraception and anti-epileptic drug therapy, and of the risk of causing abnormality in foetuses of material use of conventional anti-epileptic medications. [HL2592]

Baroness Hayman

It is well recognised that some anti-epileptic drugs such as phenytoin (Epanutin) and possibly carbamazepine (Tegretol) and topiramate (Topamax) cause a reduction in the effectiveness of low dose combined oral contraceptives. In contrast to this, sodium valproate (Epilim), lamotrigine (Lamictal), vigabatrin (Sabril), gabapentin (Neurontin) and tiagabine (Gabitril) do not interact with combined oral contraceptives. The product particulars for all these drugs provide clear information about such interactions. This information is produced by the manufacturers, approved by the Medicines Control Agency (MCA) and is provided to prescribing doctors as the Summary of Product Characteristics and to patients as a leaflet in each pack of the medicine.

Congenital malformations have been reported in association with conventional anti-epileptic drugs such as sodium valproate (Epilim), phenytoin (Epanutin) and carbamazepine (Tegretol). For newer anti-epileptics mentioned in the previous section, clinical experience is not as extensive. It is difficult to determine whether it is the disease itself or the anti-epileptics used in its treatment which are responsible for the increased malformation rate seen in children of epileptic women.

All product particulars for these medicines, give information about the safety of use during pregnancy and recommend that they are only to be used if the physician considers that the expected benefits to the mother outweigh the risks to the foetus.

However, the withdrawal of anti-epileptic drugs during pregnancy is not generally advisable because fetal hypoxia due to maternal seizuress is damaging and patients with severe epilepsy may develop life-threatening convulsions (status epilepticus) if treatment is stopped. Doctors, therefore, have to weigh the benefits of treating the mother's epilepsy during her pregnancy, minimising the risk of seizures, against the risk of adverse effects that the anti-epileptic drugs may have on the foetus.

The Committee on Safety of Medicines and the MCA have published relevant articles in the drug safety bulletin Current Problems in 1983 and 1993. 'This bulletin is routinely sent to all doctors and pharmacists in the United Kingdom.