<prompt> Which analgesic is not used in Acute myocardial infarction -MorphinePentazocinePethidineBuprenorphine  <response>: Ans. is b i.e., Pentazocine Its use is associated with tachycardia rise in BP is due to sympathetic stimulation. This increases cardiac work and hence is better avoided in coronary ischemia and myocardial infarction. Note - Petnidine also causes tachycardia anticholinergic action -- contraindicated in MI. 