Drug Interactions.

• American Family Physicians Clinically Significant Drug Interactions

STATINS

Concomitant use of statins and erythromycin, itraconazole, niacin or gemfibrozil (Lopid) can cause toxicity that manifests as elevated serum transaminase levels, myopathy, rhabdomyolysis and acute renal failure.¹⁹ Used alone, any statin can cause these adverse effects. However, the risk of toxicity increases when statins are coadministered with certain drugs. Because this risk may be dose-dependent, the dosage should be limited to the equivalent of 20 mg of lovastatin per day when any statin is given in combination with an interacting drug.

Lithium

If diuretic or NSAID is necessary, the dosage of lithium should be reduced by 50 percent. Signs or symptoms of lithium toxicity involve the central nervous system (drowsiness, confusion, hand tremor, blurred vision, vertigo and seizures), gastrointestinal tract (nausea and vomiting) and cardiovascular system (arrhythmias and widening of the QRS complex).

Antiepileptics

Specific data support interactions between the following drugs: erythromycin and carbamazepine; cimetidine and carbamazepine or phenytoin; fluconazole and phenytoin; and rifampin and phenytoin. Serum antiepileptic drug levels should be monitored in patients who receive any of these combinations

Warfarin

Click on ther link top of page - even panadol can be a problem.