Some prescription medicines can cause negative reactions that vary from drug to drug and person to person. These reactions range from mild to severe, and are relatively uncommon.
Certain classes of drugs (groups of drugs that are similar, but not exactly the same) are known to cause reactions in some people. These include anticonvulsants (used to control seizures), sulfonamides (a class of antibiotics) and some drugs used to control human immunodeficiency virus (HIV). However, any drug or drug group may occasionally cause drug rashes.
Not all drug rashes need to be treated. Sometimes a rash may cause only mild discomfort and have no effect on internal organs. If the drug works well, you may choose to tolerate the rash as a minor side effect. In some cases the rash or other symptoms may be more noticeable, but you can simply stop taking the medicine and the rash will go away in a week or two. Always notify your physician if you need to stop a medication.
Other drug reactions can be serious. Some rashes can be accompanied by severe anaphylaxis, a sudden and severe allergic reaction that occurs within minutes after taking the medicine. Symptoms of anaphylaxis include difficulty breathing, facial and oral swelling and unconsciousness. Another severe reaction is Stevens-Johnson syndrome, which includes a painful, blistering rash on the skin. There may also be erosions in the mouth, and this severe reaction can affect internal organs. Other aspects of Stevens-Johnson syndrome are inflammation inside the eye and damage to the clear outer area of the eye, the cornea.
It is important to ask your physician about possible reactions before you take any prescription drug. Knowing what to watch for can help you respond appropriately if you do have a rare, but potentially serious reaction.
Prescription drug reactions do not happen often, and when they do, the reaction often goes away soon after you stop taking the medication. When reactions are more severe, we can diagnose drug rashes and other skin reactions quickly so you can get the treatment you need. Our emergency room physicians are well versed in rapid treatment of severe drug reactions, and we are on call to assess and treat rashes and other symptoms.