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Classification: C

Drug products: Topamac, Topamax, Topimax, Topimax®, Topiramat 1A Farma, Topiramat 2care4, Topiramat Actavis, Topiramat Bluefish, Topiramat Ebb, Topiramat Orifarm, Topiramat Orion, Topiramat ratiopharm

ATC code: N03AX11

Substances: topiramate


Topriamate is used in focal epilepsy with or without generalization, in primary generalized tonic-clonic seizures, and as a migraine prophylactic. No difference between men and women in efficacy or safety has been reported.

Studies show conflicting results regarding sex differences in weight loss during treatment with topiramate.

During pregnancy the concentration of topiramate falls with 30-40%.

Additional information

Pharmacokinetics and dosing

In women, the volume of distribution of topiramate is about 50% less than in men. This is attributed to the higher percentage of body fat in women. This difference is not considered to be clinically relevant [1]. No sex differentiation in dosing has been recommended [2].


Evaluation studies in clinical trials have shown no impact of sex on effectiveness and safety of topiramate, regardless of indication [3]. Five randomized, double-blind, placebo-controlled trials of topiramate as add-on therapy in patients with medically intractable partial-onset seizures showed no difference in efficacy by sex. However, women represented only 20% of the 534 patients studied [4].

Adverse effects

Treatment with topiramate may cause weight loss. Some studies suggest that there are no sex differences in weight loss in adults, while others observe a predictor value of female sex for BMI S.D.S. (standard deviation score) at 12 months [5].

Reproductive health issues

Topiramate may reduce the plasmaconcentration of estrogens and progestins. Regarding drug-drug interactions aspects, please consult Janusmed Interactions (in Swedish, Janusmed interaktioner).

Physiologic changes during pregnancy can alter antiepileptic pharmacokinetics and total antiepileptic concentration. Pharmacokinetics of some antiepileptic drugs are more pronounced, probably due to pregnancy-related differential effects on cytochrome P450 enzymes and pregnancy-related changes in the volume of distribution [6]. Topiramate serum concentrations have been reported to decline by up to 30-40% during the third trimester of pregnancy, but with a considerable interindividual variation [7]. Regarding teratogenic aspects, please consult Janusmed Drugs and Birth Defects (in Swedish, Janusmed fosterpåverkan).

Updated: 2018-09-19

Date of litterature search: 2013-03-11


  1. Vovk T, Jakovljević MB, Kos MK, Janković SM, Mrhar A, Grabnar I. A nonlinear mixed effects modelling analysis of topiramate pharmacokinetics in patients with epilepsy. Biol Pharm Bull. 2010;33:1176-82. PubMed
  2. Topimax (topiramat). Summary of Product Characteristics. Medical Products Agency Sweden; 2016. länk
  3. Topiramate. DailyMed [www]. US National Library of Medicine. [updated 2013-01-01, cited 2013-03-11]. länk
  4. Morrell MJ. The new antiepileptic drugs and women: efficacy, reproductive health, pregnancy, and fetal outcome. Epilepsia. 1996;37 Suppl 6:S34-44. PubMed
  5. Verrotti A, Scaparrotta A, Agostinelli S, Di Pillo S, Chiarelli F, Grosso S. Topiramate-induced weight loss: a review. Epilepsy Res. 2011;95:189-99. PubMed
  6. Legato MJ, editor. Principles of Gender-Specific Medicine. Academic Press Inc; 2004.
  7. Tomson T, Landmark CJ, Battino D. Antiepileptic drug treatment in pregnancy: changes in drug disposition and their clinical implications. Epilepsia. 2013;54:405-14. PubMed
  8. Läkemedelsstatistik. Stockholm: Socialstyrelsen. 2015 [cited 2016-04-29] länk

Authors: Linnéa Karlsson Lind, Desirée Loikas

Reviewed by: Expertrådet för neurologiska sjukdomar, Ellen Vinge, Lars Lööf

Approved by: Mia von Euler