Monograph: |
Oxprenolol Hydrochloride
A white or almost white crystalline powder. Very to freely
soluble in water; freely soluble in alcohol and chloroform;
sparingly soluble in acetone; practically insoluble in ether. A
10% solution in water has a pH of 4 to 6. Protect from light.
Adverse Effects, Treatment, and Precautions
As for beta blockers, like propranolol.
Effects on the gastro-intestinal tract : Retroperitoneal fi-
brosis in one patient associated with the use of oxprenolol.
Hypersensitivity. A report of oxprenolol-induced drug fe-
ver in a patient which was confirmed by a challenge test.
Overdosage. A report of rhabdomyolysis and myoglobinu-
ria complicating severe overdosage with oxprenolol.
I. Schofield PM. et al. Recovery after severe oxprenolol overdose
complicated by rhabdomyolysis
Interactions
The interactions associated with beta blockers, like
propranilol.
Pharmacokinetics
Oxprenolol is well absorbed from the gastro-intesti-
nal tract, but is subject to first-pass metabolism re-
sulting in variable bioavailability (20 to 70%). Peak
plasma concentrations have been reported to occur
about I or 2 hours after a dose. Oxprenolol is 80%
bound to plasma proteins. Oxprenolol is metabo-
lised in the liver and almost entirely excreted in the
urine. Oxprenolol diffuses across the placenta and is
present in breast milk. It is moderately lipid-soluble
and crosses the blood-brain barrier. An elimination
half-life of I to 2 hours has been reported.
Pregnancy and breast feeding. A study of the placenta)
transfer of oxprenolol and its passage into breast milk in 32
pregnant women receiving oxprenolol in association with di-
hydralazine (Trasipressol). At delivery the mean maternal
plasma concentration was 0.386 nmol per mL compared with
0.071 and 0.081 nmol per mL in plasma from the umbilical
artery and vein respectively. Oxprenolol plasma concentra-
tions in the newborn ranged from 0 to 0.186 nmol per mL dur-
ing the first 24 hours of life. The concentrations of oxprenolol
in breast milk 3 to 6 days after delivery ranged from 0 to
1.342 nmol per mL, and the milk to plasma concentration ra-
tio was 0.45:1. Based on the highest milk concentration ob-
served it was calculated that a breast-fed infant could receive,
at a maximum, a daily dose at least sixty times less than an
average daily dose (240 mg daily) taken by a hypertensive
adult.
Uses and Administration
Oxprenolol is a non-cardioselective beta blocker. It is reported
to possess intrinsic sympatho-
mimetic and membrane-stabilising activity.
Oxprenolol is used as the hydrochloride in the man-
agement of hypertension , angina pectoris, and cardiac
arrhythmias . It is also
used in anxiety disorders .
In hypertension oxprenolol hydrochloride is given
by mouth in a usual dose of 80 to 160 mg daily in
two or three divided doses. The dose maybe in-
creased at weekly or fortnightly intervals until a sat-
isfactory response is achieved. The usual maximum
dose is 320 mg daily although up to 480 mg daily
has been allowed. Modified-release tablets may be
given once daily in a dose of up to 320 mg.
The usual dose for angina pectoris is 80 to 160 mg
daily in two or three divided doses with a usual max-
imum of 320 mg daily. For cardiac arrhythmias a
dose of 40 mg daily to not more than 240 mg daily
in two or three divided doses may be used.
For the emergency treatment of cardiac arrhythmias
oxprenolol hydrochloride has been given by slow in-
travenous injection or by the intramuscular route.
Oxprenolol hydrochloride is given by mouth in usu-
al doses of 40 to 80 mg daily, either as a single dose
or in two divided doses, to relieve anxiety in stress-
ful situations.
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