ALPHA-ADRENERGIC NEURON BLOCKING AGENT

Guanethidine (Ismelin)

Guanadrel

Bethanidine

Debrisoquin

Type of adrenergic neuron blocking agent

Debrisoquin

An adrenergic neuron blocking agent that was withdrawn from the market because of potential drug-drug interactions

inhibit release of neurotransmitter like Alpha 2 Lower blood pressure by preventing normal physiologic release of norepinephrine from postganglionic sympathetic neurons. (with local anesthetic activity)

• membrane-stabilizing activity

Adrenergic neuron blocker MOA

for severe hypertension

Adrenergic neuron blocker use

Decrease CO due to bradycardia and relaxation of capacitance vessels

Guanethidine in the earlly course of the theraphy

decrease PVR

Guanethidine in the long term of theraphy

Edema

Sodium and water retention

Guanethidine the compensatory effect

hypertensive crisis

Guanethidine is not given in?

Polar ; does not cross BBB --no CNS effects

Does Guenethidine cross the BBB?

Long half life (5 days)

Guanethidine half life

maximal effect in 1-2 weeks

Onset of sympathoplegia is gradual of Guanethidine for approximately?

Guanethidine

Do not increase the dose at intervals shorter than 2 weeks.

Postural hypotension, diarrhea (PS), and impaired ejaculation (S) *** RARELY USED NOWADAYS

Toxicities involved in Guanethidine

Reserpine

block the storage of catecholamines in the vesicle used for treating mild to moderate hypertension

Serpasil

BN of reserpine

Reserpine

An adrenergic blocker that rapidly enters the brain

Sedation

Mental depression

Parkinsonism symptoms

The depletion of cerebral amine stores of reserpine causes?

Produces mild diarrhea and gastrointestinal cramps and increases gastric acid secretion

Reserpine produces what side effects?

Blocks the uptake and the storage of biogenic amines → Depletion of norepinephrine, dopamine, and serotonin in both central and peripheral neurons. → decrease CO & PVR

Adrenergic blocking agent MOA