Guanethidine Uses, Dosage, Side Effects, Food Interaction and all others data.

An antihypertensive agent that acts by inhibiting selectively transmission in post-ganglionic adrenergic nerves. It is believed to act mainly by preventing the release of norepinephrine at nerve endings and causes depletion of norepinephrine in peripheral sympathetic nerve terminals as well as in tissues. [PubChem]

High blood pressure can cause the heart and arteries to not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled. Guanethidine works by decreasing the heart rate and relaxing the blood vessels so that blood can flow more easily through the body, thereby reducing these risks. It is a postganglionic sympathetic nerve terminal blocker that prevents the release of norepinephrine from nerve terminals.

Trade Name Guanethidine
Availability Discontinued
Generic Guanethidine
Guanethidine Other Names guanéthidine, Guanethidine, guanethidinum, guanetidina
Related Drugs amlodipine, lisinopril, metoprolol, losartan, furosemide, hydrochlorothiazide, hydralazine, nifedipine, captopril, enalapril
Type Oral
Formula C10H22N4
Weight Average: 198.3085
Monoisotopic: 198.184446724
Groups Approved
Therapeutic Class
Available Country United States
Last Updated: September 19, 2023 at 7:00 am


Guanethidine is an antihypertensive agent used in the management of moderate and severe hypertension, either alone or as an adjunct, and for the management of renal hypertension.

For the treatment of moderate and severe hypertension, either alone or as an adjunct, and for the treatment of renal hypertension.

How Guanethidine works

Guanethidine acts at the sympathetic neuroeffector junction by inhibiting or interfering with the release and/or distribution of norepinephrine (NE), rather than acting at the effector cell by inhibiting the association of norepinephrine with its receptors. It is taken up by norepinephrine transporters to be concentrated within the transmitter vesicles in place of NE, leading to gradual depletion of NE stores in the nerve endings. Guanethidine at the nerve terminal blocks the release of noradrenaline in response to an action potential. In contrast to ganglionic blocking agents, Guanethidine suppresses equally the responses mediated by alpha-and beta-adrenergic receptors but does not produce parasympathetic blockade. Since sympathetic blockade results in modest decreases in peripheral resistance and cardiac output, Guanethidine lowers blood pressure in the supine position. It further reduces blood pressure by decreasing the degree of vasoconstriction that normally results from reflex sympathetic nervous activity upon assumption of the upright posture, thus reducing venous return and cardiac output more.


Side effects include drowsiness, dizziness, tiredness or confusion. LD50=1000 mg/kg (mouse, oral)

Food Interaction

  • Take with or without food. The absorption is unaffected by food.

Guanethidine Disease Interaction

Moderate: peripheral edema

Elimination Route

3-30% of oral dose (poor and highly variable)

Half Life

1.5 days


  • Renal cl=56 ml/min

Elimination Route

Ismelin is converted by the liver to three metabolites, which are excreted in the urine.

Innovators Monograph

You find simplified version here Guanethidine
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