What is sympatholytic action?

What is sympatholytic action?

A sympatholytic (or sympathoplegic) drug is a medication that opposes the downstream effects of postganglionic nerve firing in effector organs innervated by the sympathetic nervous system (SNS). They are indicated for various functions; for example, they may be used as antihypertensives.

What is the mechanism of action of sympatholytics?

Central sympatholytic drugs reduce blood pressure mainly by stimulating central α(2) -adrenergic receptors in the brainstem centers, thereby reducing sympathetic nerve activity and neuronal release of norepinephrine to the heart and peripheral circulation.

What drug is central sympatholytics?


Drug Total Dose Range, mg/d Half‐Life, h
Clonidine patch 0.1–0.6 14–26
Guanabenz 8–32 6–14
Guanfacine 1–3 10–30
Methyldopa 250–2000 1–2

What drugs are sympatholytic?


Drug Target Type
Methyldopa Aromatic-L-amino-acid decarboxylase enzyme
Guanethidine Sodium-dependent noradrenaline transporter target
Nadolol Beta-1 adrenergic receptor target
Nadolol Beta-2 adrenergic receptor target

Are beta-blockers sympatholytics?

Beta-blockers are drugs that bind to beta-adrenoceptors and thereby block the binding of norepinephrine and epinephrine to these receptors. This inhibits normal sympathetic effects that act through these receptors. Therefore, beta-blockers are sympatholytic drugs.

Is prazosin a sympatholytic?

It is an α1-blocker that acts as an inverse agonist at alpha-1 adrenergic receptors. It can be primarily used to treat high blood pressure and post-traumatic stress disorder as a sympatholytic drug.

Are alpha blockers sympatholytic?

Sympatholytic drugs include alpha- and beta-adrenergic receptor antagonists (alpha blockers and beta blockers) as well as centrally acting agents such as clonidine, guanabenz, methyldopa, minoxidil, and reserpine.

Are beta blockers sympatholytics?

Are beta-blockers Sympatholytics?

Which therapeutic index is the safest?

The larger the therapeutic index (TI), the safer the drug is. If the TI is small (the difference between the two concentrations is very small), the drug must be dosed carefully and the person receiving the drug should be monitored closely for any signs of drug toxicity.

Does atenolol cause bronchoconstriction?

Cardioselective ß blockers such as atenolol and metoprolol are at least 20 times more potent at blocking ß-1 receptors than ß-2 receptors. At therapeutic doses the ß-2 blocking effect, and therefore the risk of bronchoconstriction, is negligible.