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s ? overdosage by inhalation can produce fatal ventricular arrhythmia ? Contraindication: myocarditis ,coronary heart disease。 ? supraventricular paraxosmal ? pupil mydriasis (Phenylephrine) α2R agonists ? Oxymetazoline, apraclondine ? Clonidine, methyldopa βR agonist ? β1 and β2R agonist ? Isoprenaline: lower selectivity to both β1 and β2R, little effect on αR pharmacological Effects ? heart: positive inotropic effect ,increase the heart rate and conduction, cardiac output increase ? blood vessels : reduction of peripheral vascular resistance in skeletal muscle, renal and mesenteric vascular beds。Block the release of histamine(β2 effects) – gastrointestinal tract – bladder – Eye: ocular pressure reduction – skeletal muscle Pharmacological Effects ? Metabolic effects – increase in glucoses and lactate production via glycogenolysis – inhibition of insulin secretion (αR) – increase in free fatty acid and oxygen consumption . Pharmacological Effects ? CNS – At therapeutic doses – In toxic doses, excitement, agitation, convulsion pharmacokiics ? Adr absorption is poor with oral administration ? Adr absorption is slow with hyodermic administration ? can be given iv or im Therapeutic Uses ? cardiac arrest ? anaphylactic shock ? Asthma and acute hypersensitivity reaction ? prolong the duration of local