Monograph: |
Benserazide Hydrochloride
A white or yellowish-white or orange-white crystalline pow-
der. Benserazide hydrochloride 28.5 mg is approximately
equivalent to 25 mg of benserazide. Freely soluble in water:
slightly soluble in dehydrated alcohol: sparingly soluble in
acetone. A 1% solution in water has a pH of 4.0 to 5.0. Pro-
tect from light.
Solubility. Benserazide is unstable in a neutral, alkaline, or
strongly acidic medium.'
Adverse Effects and Precautions
Developmental abnormalities of the rat skeleton have been
reported with benserazide by Theiss and SchSrer.' but Ziegler
et al. found no evidence of any disorder involving bone me-
tabolism in man.Nevertheless the manufacturers have rec-
ommended that benserazide should not be given to patients
under 25 years of age or to pregnant women.
Pharmacokinetfes
Phannacokinetic and metabolic studies of benserazide in an-
imals and man.Following oral administration to parkinso-
nian patients benserazide was rapidly absorbed to the extent
of about 58%, simultaneous administration of levodopa tend-
ing to increase this slightly. It was rapidly excreted in the
urine in the form of metabolites. mostly within the first 6
hours; 85% of urinary excretion had occurred within 12
hours. Benserazide is predominantly metabolised in the gut
and appears to protect levodopa against decarboxylation pri-
marily in the gut. but also in the rest of the organism, mainly
by way of its metabolite trihydroxybenzylhydrazine. Bensei-
azide did not cross the blood-brain barrier in rats.
Uses and Administration
Benserazide hydrochloride is a peripheral decarboxylase in-
hibitor with actions similar to those of carbidopa and
is used similarly as an adjunct to levodopa in the treatment of
parkinsonism . For details of administration and dos-
age, see Levodopa.
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