Pharmacological Action of Sympathomimetic drugs

May 24, 2012 | By | Reply More

Pharmacological Action of Sympathomimetic drugs


  • increases the heart rate, force of myocardial contraction and cardiac output which is associated with increased metabolism by the myocardium, increased oxygen consumption and thus decreasing cardiac efficiency.

Blood vessels:

  • constrict the blood vessels of skin and mucous membranes.
  • Constriction predominates in cutaneous and mucous membranes which occur through both α1 and α2 receptors.
  • dilates the blood vessels of the skeletal muscles
  • Blood pressure:


  • decrease in total peripheral resistance.
  • simultaneously lowers the blood pressure by its peripheral action.
  • rise in systolic blood pressure is often followed by decrease in blood pressure
  • mean blood pressure rises with increase in pulse pressure.


  • causes rise in systolic, diastolic and mean blood pressure


  • causes relaxation of smooth muscles of GIT and reduce its motility.

Respiratory system:

  • cause bronchodilatation

Action on CNS:

  • do not produce any marked CNS effects because they do not cross blood brain barrier


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Category: Pharmacology

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