So yesterday a patient showed up at the clinic with a massive swelling in his left face region. Upon examination it was found to be due to infected first premolar. Dentist recommended him to get the tooth extracted as the patient also had generalized attrition and abrasion. The patient was an asthmatic and diabetic on Ecosprin. The dentist while prescribing him medicines said that he won't prescribe him Ibuprofen as the patient was asthmatic. I have been looking for an explanation since then and Rang and DaLe have something to say about the isomers of COX enzyme. I am looking for a simple explanation.
Ibuprofen is an NSAID. So it acts by inhibiting COX (Cyclooxygenase) enzyme. What it signifies is that, if COX enzyme has been blocked, the PUFA (say arachidonic acid, here) will be converted to leukotrienes through lipoxygenase pathway.
Leukotrienes (LT) are of different types and have several target receptors; one of which is CysLT-receptors on bronchial smooth muscle. Once they are activated through LTD$_4$,E$_4$,C$_4$ , bronchospasm will occur. For asthma patients this is really fatal. So for them Ibuprofen is contraindicated.
Lo, P.C., Tsai, Y.T., Lin, S.K. and Lai, J.N., 2016. Risk of asthma exacerbation associated with nonsteroidal anti-inflammatory drugs in childhood asthma: a nationwide population-based cohort study in Taiwan. Medicine, 95(41).