Drug Allergy
• Definition
· Drug allergy is the condition of an inappropriate immune response to a medication. The immune system incorrectly responds as if the drug was a harmful bacteria or infection.
If you think of the immune system as an army, a drug allergy would be friendly fire, or an attack on an ally.
• Overview
· Drug allergy is more likely to occur with certain medications, these drugs are more allergenic (allergy producing).
The most common allergy producing drugs are:
· penicillin-type medications
· sulfur medications
· certain seizure medications like phenytoin and carbamazepine
· allopurinol
· muscle relaxants used for general anesthesia
· nonsteroidal anti-inflammatory drugs
· antiarrhythmic agents
· Drug allergies are usually over diagnosed and it is estimated that only 10% or less of adverse reactions to drugs are true allergic reactions.
Having multiple drug allergies is quite rare.
Side effects to medications are different from an allergy. For example, many people have nausea when taking codeine. This is a common side effect of the medication and not an allergy.
Idiosyncratic reactions (unexplained side effects) from medications are distinct from allergies and do not result result from an immunologic reaction.
References
Gruchalla R: Understanding drug allergies. J Allergy Clin Immunol 2000;105(6 Pt 2):S637.
Posted on March 23, 2009
