Common Side Effects Of Analgesics

Rash Or Itching

Some individuals who utilize acetaminophen and opioid-based analgesics may experience the development of a rash or itching. The first thought when it comes to itching and a rash with the use of any drug is an allergic reaction. However, this type of allergic reaction tends to be exceedingly rare with opioid-based analgesics. The mechanism more commonly responsible for this adverse side effect is called a pseudoallergy or a hypersensitivity reaction. Psuedo-allergic reactions tend to only occur upon the first use of the drug, where a true allergic reaction requires individuals to have taken it multiple times. The reason this hypersensitivity occurs is because some of the opioid receptors in the brain and spinal cord responsible for pain signaling the medication binds itself to can also trigger itching sensations. Similar to other adverse side effects of analgesics, a rash or itching may be persistent or dissipate as the individual's body adjusts to it over numerous regular doses.