Inflammation I
Anti-inflammatory medications (NSAIDs, acetaminophen, and steroids) are great adjuvants to centrally acting opioid medications as they act peripherally to reduce inflammation. If either class of medications causes undesirable side effects at higher dosages, combinations at reduced dosages of each can be effective. Medicines in this class also have an antipyretic effect.
While there is some debate in the literature, if a patient fails to obtain pain relief from an NSAID trial of two weeks, it is reasonable to consider a trial of an NSAID from a different class. Review the Classes of Medicine.
Acetaminophen is not strictly an anti-inflammatory medication as it crosses the blood-brain barrier and acts centrally to inhibit prostaglandins; however, it does have significant pain-relieving properties and is reasonable to consider in patients who cannot take other NSAIDs due to side effects.
The rest of the NSAIDs act peripherally to inhibit prostaglandin synthesis by inhibiting cyclooxygenase (COX) to decrease the production of prostaglandin and thromboxane, which have far-reaching effects on the body.
With regard to pain, prostaglandins induce inflammation and sensitize the peripheral terminals of C fibers to thermal, mechanical, and chemical stimuli. Because of this sensitization, the chemical mediators exert a greater effect on the pain receptors.
There are two isomers of the COX enzyme. COX-1 is usually present in the body, but COX-2 is only present after it is induced by inflammation. Most side effects of NSAIDs are due to their effect on COX-1, but most treatment effects are due to the effect on COX-2.