Topiramate Flashcards
1
Q
What dose is topiramate started at and titrated up to according to the BNF?
A
- Start at 25mg at night for 1 week.
- Increase in 25mg steps weekly.
- Usual dose is 50-100mg a day in 2 divided doses.
2
Q
What is the pharmacological action of topiramate?
A
It is an enzyme inducer of the P450 enzyme CYP34.
3
Q
Because it is an enzyme inducer, what do FSRH (Faculty of Sexual and Reproductive Health) recommend?
A
- AEDs (phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine) that induce liver enzymes may reduce the contraceptive efficacy of combined contraceptive methods, progestogen-only pills and progestogen-only implants.
- Therefore POP and COCP are UKMEC 3. (Disadvantages outweigh the advantages)
- Implant is UKMEC 2.
- IUS, IUD and Depo-provera are all UKMEC 1 and aren’t affected by AED.
4
Q
Topiramate was originally developed as an antiepileptic & enzyme inducer and thus can effect hormonal contraceptives. What other AEDs can also do this?
A
- Phenytoin
- Carbamazepine
- Barbiturates
- Primidone
- Topiramate
- Oxcarbazepine
5
Q
What are some adverse side effects of topiramate?
A
- weight loss
- dizziness
- paraesthesia
- lethargy and poor concentration
- rare but important: acute myopia and secondary angle closure glaucoma
