Whenever doctors consider prescribing a drug, they must weigh the possible risks against the expected benefits. Use of a drug isn't justified unless the expected benefits outweigh the possible risks. Doctors must also consider the likely outcome of withholding the drug. Potential benefits and risks can seldom be determined with mathematical precision. When assessing the benefits and risks of prescribing a drug, doctors consider the severity of the disorder being treated and the impact it's having on the patient's quality of life.
Many factors can increase the likelihood of an adverse drug reaction.
They include the simultaneous use of several drugs, very young or old age, pregnancy, certain diseases, and hereditary factors. The number and severity of adverse reactions increase disproportionately with the number of drugs taken. The use of alcohol, which is also a drug, increases the risk. Having a doctor or pharmacist periodically review all the drugs a person is taking can reduce the risk of an adverse drug reaction. Age Infants and very young children are at special risk of adverse drug reactions because their capacity to metabolize drugs is not fully developed.