NEET MDS Lessons
Pharmacology
BradyKinin
An endogenous vasodilator occurring in blood vessel walls.
At least two distinct receptor types, B1 and B2, appear to exist for BradyKinin
Roles of bradykinin:
1) Mediator of inflammation and pain.
2) Regulation of microcirculation.
3) Their production is interrelated with clotting and fibrinolysin systems.
4) Responsible for circulatory change after birth.
5) Involved in shock and some immune reactions.
Beta - Adrenergic Blocking Agents
Mechanisms of Action
- Initial decrease in cardiac output, followed by reduction in peripheral vascular resistance.
- Other actions include decrease plasma renin activity, resetting of baroreceptors, release of vasodilator prostaglandins, and blockade of prejunctional beta-receptors.
Advantages
- Documented reduction in cardiovascular morbidity and mortality.
- Cardioprotection: primary and secondary prevention against coronary artery events (i.e. ischemia, infarction, arrhythmias, death).
- Relatively not expensive.
Considerations
- Beta blockers are used with caution in patients with bronchospasm.
- Contraindicated in more than grade I AV, heart block.
- Do not discontinue abruptly.
Side Effects
- Bronchospasm and obstructive airway disease.
- Bradycardia
- Metabolic effects (raise triglyerides levels and decrease HDL cholesterol; may worsen insulin sensitivity and cause glucose intolerance). Increased incidence of diabetes mellitus.
- Coldness of extremities.
- Fatigue.
- Mask symptoms of hypoglycemia.
- Impotence.
Indications
- First line treatment for hypertension as an alternative to diuretics.
- Hypertension associated with coronary artery disease.
- Hyperkinetic circulation and high cardiac output hypertension (e.g., young hypertensives).
- Hypertension associated with supraventricular tachycardia, migraine, essential tremors, or hypertrophic cardiomyopathy.
Beta adrenergic blocker Drugs
Atenolol 25-100
Metoprolol 50-200
Bisoprolol 2.5-10