Monograph: |
Mepivacaine Hydrochloride
A white odourless crystalline powder. Freely soluble in
water, in alcohol, and in methyl alcohol; very slightly soluble
in chloroform and in dichloromethane: practically insoluble
in ether. A 2% solution in water has a pH of 4.0 to 5.0.
pH of solutions. For a discussion of the effect that pH has
on the stability of local anaesthetic solutions and the pain as-
Adverse Effects, Treatment, and Precautions
As for local Anaesthetics in general like lignocaine
Interactions
For interactions associated with local anaesthetics.
Studies in vitro showed that bupivacaine dramatically reduce
the binding of mepivacaine to alpha-1-acid glycoprotein.
Pharmacokinetics
Mepivacaine is highly bound to plasma protein:
(about 78%). The plasma half-life has been reported
to be about 2 to 3 hours in the adult and about
hours in the neonate. It is rapidly metabolised in the
liver and less than 10% of a dose is reported to bi
excreted unchanged in the urine. Several metabo
lites are also excreted via the kidneys and includi
glucuronide conjugates of hydroxy compounds ani
an N-demethylated compound, 2'.6'-pipecoloxylid
ide (PPX). Over 50% of a dose is excreted as metab
olites into the bile but these probably undergi
enterohepatic circulation as only small amounts ar
excreted in the faeces. Mepivacaine crosses the pla
centa.
See also under Local Anaesthetics, like lignocaine.
Pregnancy: There is considerable transfer of mepivacaine
across the placenta following maternal administration and the
ratio of fetal to maternal concentrations is in the order of 0.7
Although neonates have a very limited capacity to metabolize
mepivacaine it appears they are able to eliminate the drug.
Uses and Administration
Mepivacaine hydrochloride is a local anaesthetic
the amide type with actions and uses similar to those
It is used for infiltration, pe-
ripheral nerve block, and epidural anaesthesia
Mepivacaine has a rapid onset and an inter-
mediate duration of action. The speed of onset and
duration of action are increased by the addition of
vasoconstrictor and absorption into the circulation
from the site of injection is reduced.
The dosage of mepivacaine used depends on the site
of injection and the procedure used. An adult dose
of mepivacaine hydrochloride should not generally
exceed 400 mg and the total dose in 24 hours should
not exceed I g. Doses should be reduced in the eld-
erly, in debilitated patients, and in those with cardiac
or hepatic impairement. A suggested maximum dose
for children, especially less than 3 years of age is 5
to 6 mg per kg body-weight. Concentrations of less
than 2% should also be used for children less than 3
years of age.
For infiltration anaesthesia up to 400 mg of a I %
(40 mL) or 0.5% (80 mL) solution is used. For den-
tal infiltration and nerve block a 2% solution with a
vasoconstrictor or a 3% plain solution is used. For
anaesthesia at a single site in the jaw a dose of 36 mg
(1.8 mL) of the 2% solution or 54 mg (1.8 mL) of
the 3% solution is used. For anaesthesia of the entire
oral cavity 180 mg (9 mL) of the 2% solution or
270 mg (9 mL) of the 3% solution is used. Some
recommend that no more than 300 mg should be ad-
ministered at a single dental sitting.
For peripheral nerve blocks, namely cervical, bra-
chial plexus, intercostal, and pudenda! blocks, I or
2% solutions may be used in doses of 50 to 400 mg
(5 to 40 mL) as a 1% solution, or 100 to 400 mg (5
to 20 mL) as a 2% solution. For pudenda] block half
of the dose is injected on each side. For paracervical
block a dose of up to 100 mg (10 mL) of a 1% solu-
tion on each side has been suggested allowing an in-
terval of 5 minutes between sides. This may be
repeated at an interval of not less than 90 minutes.
and for a combined paracervical and pudenda! block
up to 150 mg (15 mL) of a I % solution is injected on
each side. For therapeutic nerve block in the man-
agement of pain 10 to 50 mg (I to 5 mL) of a 1%
solution or 20 to 100 mg (I to 5 mL) of a 2% solu-
tion may be given.
For epidural anaesthesia usual doses are: 150 to
300 mg (15 to 30 mL) of a 1% solution, 150 to
375 mg (10 to 25 mL) of a 1.5% solution, or 200 to
400 mg (10 to 20 mL) of a 2% solution. Hyperbaric
solutions of mepivacaine hydrochloride without
adrenaline have also been used for spinal anaesthesia.
Mepivacaine has been included in the intramuscular
injections of other drugs to minimise the pain Pro-
duced at the injection site.
Mepivacaine has also been used as a surface anaes
thetic but other local anaesthetics such as lignocaine
are more effective.
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