All adverse effects of theophylline are mediated by A receptor except:

Ans: (d) Gl discomfortRef. Goodman and Gill man's, The Pharmacological Basis of Therapeutics 13th edition, Page 735 11.TheophyllineBelongs to methylxanthines group of drugs.It has bronchodilator action and nonbronchodilator effects.It has various mechanisms of action:Inhibition of phosphodiesterases,Adenosine receptor antagonism,Interleukin-10 release.Prevents the translocation of the pro-inflammatory transcription factor NF-kB into the nucleus,Promotes apoptosis in eosinophils and neutrophils in vitro,Histone deacetylase activation.Side Effects:The most common side effects are headache, nausea and vomiting, abdominal discomfort and restlessness.Side effects of theophylline and proposed mechanismsSide effectProposed mechanismNausea and vomitingPDE4 inhibitionHeadachePDE4 inhibitionGastric discomfortPDE4 inhibitionDiuresisA1 receptor inhibitionCardiac arrhythmiasPDE3 inhibition, A1 receptor inhibitionEpileptic seizuresA1 receptor inhibition