July 11, 2005
Lamictal cuts effectiveness of the pill
By Richard Woodman
LONDON (Reuters Health) - Drug maker GlaxoSmithKline has issued
a "Dear Doctor" letter advising that its anti-epilepsy drug
Lamictal (lamotrigine) can reduce the effectiveness of oral
New data have demonstrated an interaction between combined
oral contraceptives and lamotrigine which could lead to reduced
effectiveness of hormonal contraceptives, a revised product
starting lamotrigine, and the use of alternative non-hormonal
methods of contraception should be encouraged," the new label
It adds: "A hormonal contraceptive should only be used as
the sole method of contraception if there is no other
"If the oral contraceptive pill is chosen as the sole
method of contraception, women should be advised to promptly
notify their physician if they experience changes in menstrual
pattern (e.g. breakthrough bleeding) while taking Lamictal as
this may be an indication of decreased contraceptive efficacy."
Lamotrigine concentrations are cut in half during
co-administration of oral contraceptives, the label further
"This may result in reduced seizure control in women on a
stable lamotrigine dose who start an oral contraceptive, or in
adverse effects following withdrawal of an oral contraceptive.
Dose adjustments of lamotrigine may be required," it advised.