PROPRANOLOL

“INDERAL”

1) Action

• Non selective Beta Adrenergic Blocker [Class II antiarrhythmic]

2) Mechanism

• Antagonises catecholamines at both b1 & b2 adrenoreceptors

• Ameliorates hypertension by: reduction of CO, reduction of SVR, inhibition of the renin production by catecholamines (mediated by b1 receptors)

3) Indications

• Angina pectoris (decrease cardiac work & reduce oxygen demand)

• Myocardial infarction

• Hypertension

• Arrhythmias [tachycardias 2° anxiety, adrenaline, digitalis]

• Migraines

• Phaeochromocytoma

• Hypertrophic subaortic stenosis (increase SV by reducing HR)

• Dissecting aortic aneurysms (reduce rate of systolic pressure development)

4) Effects on organs—side effects

• b2 blockade in lungs —> increased airway resistance

• Inhibit sympathetic stimulation of lipolysis

• Reduce insulin & glucagon secretion

5) Toxic effects/ precautions with administration

• Caution when used with calcium channel blockers

• Caution when given to diabetics

• May reduce sympathetic response during myocardial depressive drugs given during anaesthesia

6) Contraindications

• CCF: patients depends on sympathetic drive to maintain CO

• Sinus bradycardia; heart blocks

• Asthma; bronchospasm

• Right ventricular hypertrophy 2° pulmonary hypertension

7) Reversal, antagonism or antidote

• Hypotension: Adrenaline, Noradrenaline

• Bradycardia: Atropine, glucagon

• Cardiac failure: digoxin

• Bronchospasm: isoprenaline, aminophylline

8) Loading dose, maintenance dose, frequency & method of administration

• Oral

• Injection: 1mg/ml [1ml]

9) Drug’s metabolism—Drug’s excretion—Half life (pharmacokinetics)

• Elimination half life: 4 hours

• % plasma protein bound: 93

• Metabolised in liver