DESCRIPTION :
Guanethidine is an antihypertension agent that acts by inhibiting selectively transmission in post ganglionic adrenergic nerve.
MECHANISM OF ACTION :
Guanethidine acts at the sympathetic neuroeffector junction by inhibiting or interfering with the release and /or distribution of norepinephirine ,rather than acting at the effector cell by inhibiting the association of norepinephrine with its receptors. It is taken up by norepinephrine transporters. It becomes concentrated in NE stores in the nerves ending.Once inside t0 terminal it blocks the noradrenaline in response to arrival of an action potential. In contrast to ganglionic blocking agents, Guanethidine suppresses equally the response mediated by alpha- and beta adrenergic receptors but does not produce parasympathetic blockade . Since sympathetic blockade results in modest decrease in peripheral resistance and cardiac output, Guanethidine lowers blood pressure in the supine position.
PHARMACOLOGY :
• On Heart: At high blood pressure ,causing heart and arteries to not function properly.
• Damages the blood vessels of the brain, heart, kidney, resulting in stroke, heart failure. As well as risk of heart attack.
• Guanethidine is transporter by uptake 1 into the presynaptic terminal transported by norepinephrine.
• Absorption : 3.3 % of oral dose (poor and highly variable)
• Metabolism : it metabolites by liver.
• Excretion : It excreted by in the form of urine.
• Half Life : 1.5 days
THERAPEUTIC USES:
• It used to treat high blood pressure (hypertension).
• It blocks the intravenous nerve ,which used to treat chronic pain caused by complex regional syndrome.
ADVERSE EFFECTS:
• Slow heart beat
• Stuffy nose
• Unusual tiredness or weakness
• Diarrhea (due to decreasing of electrolyte content and water absorption, increase luminal osmotic load)
• Sexual problem in males
• Dizziness
• Light teadeness
DRUG- DRUG INTERACTION:
• Haloperidol + Guanethidine = Decrease the action of guanethidine, a blood pressure lowering agent.
• Chlorpromazine + Guanethidine = It may decreases the action of chlorpromazine.
REFERENCE
Tripathi KD, Essential of Medical Pharmacology ,7th edition, Page No 568
Guanethidine is an antihypertension agent that acts by inhibiting selectively transmission in post ganglionic adrenergic nerve.
MECHANISM OF ACTION :
Guanethidine acts at the sympathetic neuroeffector junction by inhibiting or interfering with the release and /or distribution of norepinephirine ,rather than acting at the effector cell by inhibiting the association of norepinephrine with its receptors. It is taken up by norepinephrine transporters. It becomes concentrated in NE stores in the nerves ending.Once inside t0 terminal it blocks the noradrenaline in response to arrival of an action potential. In contrast to ganglionic blocking agents, Guanethidine suppresses equally the response mediated by alpha- and beta adrenergic receptors but does not produce parasympathetic blockade . Since sympathetic blockade results in modest decrease in peripheral resistance and cardiac output, Guanethidine lowers blood pressure in the supine position.
PHARMACOLOGY :
• On Heart: At high blood pressure ,causing heart and arteries to not function properly.
• Damages the blood vessels of the brain, heart, kidney, resulting in stroke, heart failure. As well as risk of heart attack.
• Guanethidine is transporter by uptake 1 into the presynaptic terminal transported by norepinephrine.
• Absorption : 3.3 % of oral dose (poor and highly variable)
• Metabolism : it metabolites by liver.
• Excretion : It excreted by in the form of urine.
• Half Life : 1.5 days
THERAPEUTIC USES:
• It used to treat high blood pressure (hypertension).
• It blocks the intravenous nerve ,which used to treat chronic pain caused by complex regional syndrome.
ADVERSE EFFECTS:
• Slow heart beat
• Stuffy nose
• Unusual tiredness or weakness
• Diarrhea (due to decreasing of electrolyte content and water absorption, increase luminal osmotic load)
• Sexual problem in males
• Dizziness
• Light teadeness
DRUG- DRUG INTERACTION:
• Haloperidol + Guanethidine = Decrease the action of guanethidine, a blood pressure lowering agent.
• Chlorpromazine + Guanethidine = It may decreases the action of chlorpromazine.
REFERENCE
Tripathi KD, Essential of Medical Pharmacology ,7th edition, Page No 568
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