NEET MDS Lessons
Pharmacology
Beta-Adrenergic blocking Agents
• Prototype - Propranolol
• Prevent or inhibit sympathetic stimulation
– Reduces heart rate
– Myocardial contractility
– Reduce BP - decreases myocardial workload and O2 demand
• In long-term management used to decrease frequency and severity of anginal attacks
• Added when nitrates do not prevent anginal episodes
• Prevents exercise induced tachycardia
• Onset of action 30 min after oral dose. 1-2 min IV
Therapeutic Actions
• Block Beta adrenergic receptors in the heart and juxtaglomerular apparatus
• Decrease the influence of the sympathetic nervous system decreasing excitability of the heart
• Decrease cardiac output.
• Indicated for long term management of anginal pectoris caused by atherosclerosis
Atenolol, metoprolol, and nadolol have the same actions, uses, and adverse effects as propranolol, but they have long half-lives and can be given once daily. They are excreted by the kidneys, and dosage must be reduced in clients with renal impairment.
Heroin (diacetyl morphine)
Heroin is synthetically derived from the natural opioid alkaloid morphine
Largely owing to its very rapid onset of action and very short half-life, heroin is a popular drug of abuse
It is most effective when used intravenously
Heroin is rapidly deacetylated to 6-monoacetyl morphine and morphine, both of which are active at the mu opioid receptor
More lipid soluble than morphine and about 2½ times more potent. It enters the CNS more readily.