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Phenylephrine–acetaminophen interaction: Clinically significant or not?

KEY POINT

In healthy volunteers, administration of phenylephrine in combination with acetaminophen and ibuprofen, compared with phenylephrine alone, led to a 4-fold increase in the maximal plasma concentration of phenylephrine and a 2-fold increase in its area under the curve. Ibuprofen was subsequently found to be noncontributory to these effects. 

SOURCES

Atkinson HC et al. Increased phenylephrine plasma levels with administration of acetaminophen [letter]. N Engl J Med. 2014;370:1171–1172.
 

Hendeles L et al. Oral phenylephrine: an ineffective replacement for pseudoephedrine [letter]? J Allergy Clin Immunol. 2006;118:279–280.