ABSTRACT
There is an old but nonetheless true dictum in pharmacology: no drug has a single action. Unfortunately, multiple actions of therapeutic drugs are not always in the best interest of the subject. In addition to the primary therapeutic effect for which a drug is prescribed, the likelihood exists for the emergence of concurrent or delayed, unwanted, and potentially harmful effects-adverse reactions-which may be due to other known pharmacological or toxic effects of the drug. Such reactions also may be attributed to some idiosyncrasy in certain individuals. Any active drug, therefore, may be a doubleedged sword, doing good on one hand and perhaps harm on the other.
