Guanadrel Sulfate Chemische Eigenschaften,Einsatz,Produktion Methoden
Beschreibung
Guanadrel sulfate is an antihypertensive belonging to the class of adrenergic
neuron blocking drugs. It diminishes sympathetic vasoconstriction by inhibiting
norepinephrine storage and release from neuronal storage sites. It appears similar
in effectiveness and side effect profile to its structural relative guanethidine.
Mechanism of action
Guanadrel, like guanethidine, produces a selective block of efferent, peripheral sympathetic pathways by replacing and
depleting norepinephrine stores from adrenergic nerve endings, thus preventing the release of norepinephrine from
adrenergic nerve endings in response to sympathetic nerve stimulation. Unlike guanethidine, it does not release
norepinephrine from the adrenal medulla and reportedly depletes norepinephrine stores in the GI tract to a lesser
extent than guanethidine does. Guanadrel decreases systolic blood pressure more than diastolic blood pressure.
Pharmakokinetik
Guanadrel, unlike guanethidine, is rapidly and almost completely absorbed following oral administration. Following oral
administration, its peak plasma concentrations usually are achieved in approximately 2 hours, and its hypotensive
effect usually has an onset of 0.5 to 2.0 hours, with peak activity at 4 to 6 hours and a duration of action of 4 to 14
hours. Approximately 20% of guanadrel is bound to plasma proteins, and little, if any, of the drug crosses the
blood-brain barrier or distributes into the eye. Guanadrel has a plasma half-life of approximately 2 hours and an
elimination half-life of approximately 10 to 12 hours in patients with normal renal function. Approximately 40 to 50% of
guanadrel is metabolized in the liver to 2,3-dihydroxypropylguanidine and several unidentified metabolites, which are
excreted principally in the urine. Unlike guanethidine, approximately 85% of an oral dose of the drug is
excreted in the urine within 24 hours, with 40 to 50% of the dose excreted in the urine unchanged. In patients with impaired renal function, the half-life of guanadrel is prolonged, and apparent total body clearance and renal clearances
are decreased.
Clinical Use
Guanadrel is used in the management of hypertension, and its efficacy is similar to that of guanethidine. Guanadrel
generally is considered to be a step 2 drug and is reserved for patients who fail to respond to therapy with a step 1
drug or for cases requiring more prompt or aggressive therapy. Postural and postexercise hypotension is common in
patients receiving guanadrel, and it also is likely that heat-induced vasodilation will augment its hypotensive effect.
There is a possibility that geriatric patients may not tolerate the postural hypotensive effects of guanadrel. Being a
peripheral adrenergic neuron blocking drug, guanadrel shares the toxic potentials of guanethidine, and the usual
precautions of this drug should be observed.
Nebenwirkungen
Overall, the frequency of adverse effects produced by guanadrel is similar or less than those produced by guanethidine
and by methyldopa. In patients with impaired renal function, the elimination half-life of unmetabolized guanadrel is
prolonged and its clearance decreased, thus increasing the incidence of adverse effects if the usual dosage is
maintained in these patients.
Arzneimittelwechselwirkung
Being a peripheral adrenergic neuron blocking drug, guanadrel shares the same potential for drug interactions as
guanethidine, and the usual precautions of this drug should be observed.
Guanadrel Sulfate Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
