Changes to the prescribing information for the anti-epileptic drug Lamictal (lamotrigine) have been circulated to health care professionals in the UK by its manufacturer GlaxoSmithKline.
In a letter, GlaxoSmithKline said that new research shows an interaction between lamotrigine and oral contraceptives which may result in the reduced effectiveness of the contraceptives.
There also may be reduced seizure control in women on lamotrigine who start taking an oral contraceptive. In addition, if women taking lamotrigine stop taking oral contraceptives, there is a risk of the level of lamotrigine in the body becoming too high, which may cause unwanted symptoms. GlaxoSmithKline added that that lamotrigine levels may be decreased during pregnancy and quickly revert after birth.
An Epilepsy Action spokesperson said:
'We advise women, taking lamotrigine, first of all not to make any changes to their anti-epileptic treatment until they have sought advice from their GP or epilepsy specialist. This is because reducing or abruptly stopping anti-epileptic treatment can cause recurrent or an increasing number of seizures. Until women have sought advice from their GP they should consider using an additional form of contraception, such as the barrier method, to avoid an unwanted pregnancy.
'Women taking lamotrigine and the contraceptive pill may wish to make an appointment with their epilepsy specialist to discuss their epilepsy treatment. They should record and report any changes in their seizure pattern to their epilepsy specialist as this may be a sign that the anti-epileptic drug treatment is not effective.
'They should record any breakthrough bleeding and report this to their GP as soon as possible as this could be a sign of contraceptive failure. Women taking lamotrigine and the contraceptive pill could discuss with their GP suitable alternative contraceptive methods.
'It is important to bear in mind that several anti-epileptic drugs have a similar interaction with the contraceptive pill in that the contraceptive effect may be reduced.'
The new information on lamotrigine comes after a clinical study of 22 women taking Lamictal and a combined oral contraceptive.
- Epilepsy Action information: Lamotrigine
May 2005
The GlaxoSmithKline epilepsy medication Lamictal comes off patent on 29 May 2005. This means that other companies will be able to make their own generic versions of the drug. Lamictal is one brand name for lamotrigine.
Nothing will change for people taking Lamictal - the GlaxoSmithKline branded medication will continue to be available as usual. The only change is that pharmacists will be able to dispense both the new generic versions and the branded version.
Generic versions of drugs have to comply to strict regulations and are simply different versions of the same drug. However, Epilepsy Action and many epilepsy specialists believe that it is very important for people with epilepsy to be given the same version of their drug every time. This is because even the tiniest variations between different versions have been linked to an increase in seizures and more or different side-effects.
The NICE Guideline has recognised this issue and states that 'changing the formulation or brand of AED (anti-epileptic drug) is not recommended'. Doctors can help avoid any problems resulting from switching to and from different versions by prescribing by brand name.
If you experience any problems due to being given a different version of your drug, you can now report this on a Patient Yellow Card - a new scheme that allows patients to report problems direct to the Medicines and Healthcare Products Regulatory Agency. You may also want to ask your GP to submit a GP Yellow Card. As we are keen to monitor any changes to seizures patterns/side-effects related to switching brands of lamotrigine, please also let our Helpline know.