LABETALOL

“TRANDATE”

1) Therapeutic drug action & mechanism(pharmacology)

• alpha and beta receptor blocker

• beta receptor blockade is nonselective [both b1 & b2]

• Only example of a drug used clinically for both alpha & beta blockade; mechanism of action is to reduce BP by reducing SVR and simultaneously blocking reflex increase in heart rate

2) Indications

• Hypertension

3) Effects on organs—side effects

4) Toxic effects/ precautions with administration

5) Contraindications

• Should be avoided in asthmatics

• Diabetes and peripheral vascular disease are best treated with a selective b1-antagonist such as atenolol

• Give with caution to patients with abnormal myocardial function [eg MI or CCF] as cardiac output may be dependent on sympathetic drive resulting in cardiac decompensation

• Right ventricular failure secondary to pulmonary hypertension

• Significant right ventricular hypertrophy

• Heart blocks and bradycardias

6) Reversal, antagonism or antidote

• Bradycardia: atropine to block vagus followed by isoprenaline

• Hypotension: noradrenaline ± glucagon [direct stimulatory effect on heart bypassing adrenergic receptors]

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

• 100 mg & 200 mg tablets

• 200 to 2400 mg daily

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

• Peak plasma levels within 2 hours

• Half-life 4 hours