O inhibits renin release side or toxic effects gi

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: l, nadolol, and more selective agents including metoprolol (more β1), atenolol (more β1) – Mechanism of action • Decreases H.R. & force of contraction so decreases C.O • Inhibits renin release – Side or toxic effects • G.I. - nausea, vomiting, diarrhea • Heart - uncommon, but may cause: – serious cardiac depression – A-V block • Bronchioles - constrict airway – Contraindications - asthma or A-V block Beta blockers most useful in patients under 40. Patients over 60 do poorly but respond well to calcium channel blockers. Autonomic modifiers Autonomic • Ganglionic blocker - no longer recommended • Hexamethonium – Mechanism of action • antinicotinic drug • Inhibition of sympathetic ganglia decreases B.P. – decreases C.O. & vasoconstriction • Inhibition of parasympathetic ganglia – may increase H.R. – Therapeutically, these drugs are as good as many others, BUT too many annoying side effects. Autonomic modifiers Autonomic • Central or central and peripheral sympathetic blockers – Methyldopa (Aldomet®), clonidine, guanabenz, guanfacine • In General, these should not be used for initial treatment. Withdrawal can cause rebound hypertension. Do not miss a dose; withdraw slowly. • Sedation, dry mouth, dizziness occur frequently – Transdermal Clonidine (Catapres® patch) has a duration of one week. Side effects are minimal. – Clonidine shows experimental promise in a number of other conditions with a disturbance of catecholaminergic function » promotion of growth in children » drug withdrawal » treatment of psychiatric disorders » control of antipsychotic drug induced reactions including tardive dyskinesias. Autonomic modifiers Autonomic • Central or central and peripheral sympathetic blockers • Rauwolfia Alkaloids (reserpine) - originally to treat psychoses – Mechanism of action • Depletes Norepi in brain and heart – Side or toxic effects • CNS - sedative effect, psychic depression • G.I. - (less sympathetic so parasympathetic seen) – increases tone and motility - cramps and diarrhea – increased gastric secretion • Nasal congestion (especially in first weeks) – Contraindications • patients with depressive episodes • gastric ulcers • pregnant women (babies born with respiratory problems) Autonomic modifiers Autonomic • Monoamine Oxidase Inhibitors - Pargyline Hydrochloride – Mechanism of action - confusing • in CNS – increases norepinephrine (as needed) • in SNS...
View Full Document

Ask a homework question - tutors are online