Is acne described as an adverse drug reaction to lamotrigine (Lamictal) or topiramate (Topimax)? Do

Fråga: Is acne described as an adverse drug reaction to lamotrigine (Lamictal) or topiramate (Topimax)? Does isotretinoin (Roacutan) interact with lamotrigine or topiramate? Can Diane (cyproteronacetat and ethinylestradiol) be used as an oral contraceptive in combination with isotretinoin, lamotrigine, and topiramate? A 24-year-old woman with epilepsy since the age of 14 is being treated with lamotrigine and topiramate. The lamotrigine dose was increased in April from 125 mg to 150 mg a day while the dose of topiramate has been 50 mg a day for a long period. The patient has developed cystic acne during the last months.

Sammanfattning: There are two case-reports of acne as an adverse drug reaction to lamotrigine in higher doses.

No interaction between lamotrigine, topiramate and isotretinoin is found in the literature. None of the drugs are known as inducers of drug metabolism. Due to the paucity of available data control of the plasma levels of lamotrigine and possibly even of topiramate should be considered.

Topiramate slightly increases the clearance of ethinylestradiol. It has been recommended that the dose of ethinylestradiol, if used for contraceptive purpose, should be higher than 20 microgram (which is the case with Diane). Due to the well know teratogenic potential of isotretinoin, signs of inadequate anticonception (breakthrough bleeding) should be carefully observed and use of additional contraceptive measures is recommended.

Svar: In Swedis there is one report of acne-like skin changes following lamotrigine treatment in a child and one report of deterioration of acne after an increase in dose of lamotrigine in an adult (1). In the second case lamotrigine was discontinued and the acne disappeared.

The only skin reaction found in the literature after topiramate is folliculitis (1-3).

There are few clinical data on the interaction between isotretinoin and other drugs and no interactions between isotretinoin and lamotrigine or topiramate could be found in standard literature and databases.

Isotretinoin is eliminated by glucuronidation and/or by metabolic degradation, mainly in the liver utilizing the cytocrome P-450 system (4,5). It is known that all drugs inducing hepatic enzymes can cause enhanced glucuronidation and elimination of lamotrigine. As a precaution the plasma-levels of lamotrigine can be followed.

Topiramate increases the clearance of ethinylestradiol by 18-30 per cent (4,6). It is recommended that if ethinylestradiol is used for contraceptive purpose the dose should be higher than 20 microgram (Diane contains 35 microgram ehinylestradiol according to The Swedish catalogue of approved medical products (6).