nhs forth valley formulary 11 - Community Pharmacy

Forth Valley Formulary Eleventh Edition 2012/13Appendix 5MHRA gives the following advice:Interacting DrugPotent cytochrome P450 CYP3A4 inhibitors:HIV protease inhibitorsItraconazoleKetoconazoleErythromycinClarithromycinTelithromycinCiclosporinDanazolOther fibrates (except fenofibrate)Niacin (>1g/day)GemfibrozilVerapamil, amiodaroneDiltiazemGrapefruit juicePrescribing AdviceAvoid SimvastatinDo not exceed 10mg simvastatinAvoid but if necessary, do not exceed10mg simvastatin dailyDo not exceed 20mg simvastatinDo not exceed 40mg simvastatinAvoid grapefruit juice when takingsimvastatinPlease note – The FV antimicrobial guideline gives further advice on alternatives to macrolideantibiotics for various clinical indications. If an interacting drug, which would resultin MHRA advice to avoid simvastatin is deemed essential, an assessment shouldbe made of the individual’s immediate cardiac risk. The PRISM trial suggests thatstopping a statin in those suffering an acute coronary syndrome is associated witha significantly increased risk of death and non-fatal myocardial infarction within thefirst 30 days. In case of doubt seek specialist advice.WarfarinCare is needed when prescriging some statins to patients taking warfarin – pleasecheck the specific product information for further advice on possible interactions.Statin Side EffectsIn cases of possible statin side effects with either simvastatin or atorvastatin, astatin of different solubility should be tried. In primary prevention, pravastatin(hydrophilic) should be substituted for simvastatin (lipophilic). In secondaryprevention, rosuvastatin (hydrophilic) should be substituted for simvastatin oratorvastatin (lipophilic). Prescribing a statin of different solubility may improvetreatment and is recommended over alternative therapies.Page 61