Many people safely take several medicines together, but combinations can sometimes cause problems. One medicine may increase or reduce the effect of another, add to side effects, or both act on the same body system in a way that becomes harmful. The more medicines involved, the higher the chance of an interaction.
Interactions are not limited to prescription drugs. Over-the-counter painkillers, herbal remedies, vitamins and even certain foods or grapefruit can interact with prescription medicines. This is why a full, honest list of everything you take is so important.
Before adding anything new, including products you buy yourself, check with your pharmacist or doctor that it is safe with your current medicines. Keeping an up-to-date list of all your medicines makes these checks quick and helps avoid dangerous combinations.