In some cases, the drug interaction may result in one medication becoming less effective. For example, troglitazone may render low-dose birth control pills ineffective. Other drug interactions may increase the effects of your medications. In some cases, drug interactions can be beneficial. For example, metformin may improve the effectiveness of insulin therapy.
Some drug interactions occur quickly while others take days or even weeks to develop.
Some drug interactions are known to occur only in rare circumstances while others occur in most cases when the two drugs are used together. The best way to avoid harmful drug interactions is to be proactive. If you are taking more than six different medications each day, ask your doctor or pharmacist to perform a comprehensive drug regimen review every year. You may no longer need some of the medications. Metformin has been used to treat type 2 diabetes for 40 years in other countries and has been well tolerated.