COCP and Na Valproate (296/1700)

A 24yo girl comes to the woman sexual clinic and seeks advice for contraception. She is on
sodium valproate.
a. She can’t use COCP
b. She can use COCP with extra precaution
c. She can use COCP if anticonvulsant is changed to carbamezapin.
d. She can use COCP with estrogen 50ug and progesterone higher dose
e. She can use COCP




























answer: E

The danger with COCP is enzyme inducers which can lower the levels of the hormone in he blood, lithium is not an enzyme inducer! With Na Valproate, an inhibitor, levels will be increased, no precaution necessary as it is asking in terms of contraception

Inducers: decrease conc of drug in blood....RASAG

• rifampicin
• anticonvulsants, particularly phenytoin, carbamazepine, phenobarbitone and primidone
• spironolactone, st johns wort
• alcohol, long term
• griseofulvin

Inhibiors: increase conc of drug in blood GO SIS CCCA

• grapefruit juice 
• omeprazole
• sodium valproate
• isoniazid  
• sulphonamide
• ciprofloxacin
• cimetidine 
• clarithromycin/erythromycin 
• antifungals, amiodarone

Examples of drugs which interact with enzyme inhibitors/inducers

-        Warfarin

-        COCP

-        Theophylline

-        Corticosteroids

-        Tricyclics

-        Pethidine

-        Statins

Some other common interactions to know

• Metformin & cimetidine (inhibits renal elimination)
• Gentamycin & loop diuretics (renal failure risk)
• ACE inhibitors & potassium-sparring diuretics (risk of hyperkalaemia)
• ACE inhibitors & metformin (enhance hypoglycaemic effect)
• Statin & macrolides 
• Statin & amiodarone (increased statin concentration and therefore risk of rhabdomyolysis)
• Thiazide & PPI (hyponatraemia)
• Thiazide & lithium (increase toxicity)