Monograph: |
Camphor
Camphor is a ketone obtained from Cinnamomum camphora
(Lauraceae) and purified by sublimation, or it may be pre-
pared synthetically. The natural product is dextrorotatory and
the synthetic product is the optically inactive racemic form.
Colourless transparent or white crystals, crystalline masses.
blocks, or powdery masses known as 'flowers of camphor',
with a penetrating characteristic aromatic odour.
Soluble 1 in 800 of water. 1 in 1 of alcohol. 1 in 1 of ether,
and 1 in 0.5 of chloroform: very slightly soluble in glycerol:
freely soluble in fixed and volatile oils: very soluble in petro-
leum spirit. Store at a temperature not exceeding 25Β° in air-
tight containers.
A liquid or soft mass is formed when camphor is triturated
with chloral hydrate, menthol, phenol, and many other sub-
stances. Camphor is readily powdered by triturating with a
few drops of alcohol, ether, or chloroform. It volatilises at or-
dinary temperatures.
Adverse Effects
In addition to accidental ingestion of preparations containing
Camphor , poisoning has also occurred from administration of
camphorated oil (camphor liniment) to children in mistake for
castor oil. The symptoms include nausea, vomiting, colic,
headache, dizziness, a feeling of warmth, delirium, muscle
twitching, epileptiform convulsions, depression of the central
nervous system, and coma. Breathing is difficult and the
breath has a characteristic odour; anuria may occur. Death
from respiratory failure or status epilepticus may occur; fatal-
ities in children have been recorded from I g. There have
been reports of instant collapse in infants following the local
application of camphor to their nostrils.
Treatment of Adverse Effects
Empty the stomach by gastric lavage. Administer a saline lax-
ative and activated charcoal by mouth. Convulsions may be
controlled by the slow intravenous administration of di-
azepam or. if necessary, a short-acting barbiturate such as thi-
opentone sodium. Haemodialysis with a lipid dialysate has
been employed: the use of haemoperfusion. however, has
been criticised.
Precautions
It is dangerous to place camphor, for instance as an ointment,
into the nostrils of an infant. A small quantity applied in this
way may cause immediate collapse.
Pharmacokinetics
Camphor is readily absorbed from all administration sites. It
is hydroxylated in the liver to yield hydroxycamphor metab-
olites which are then conjugated with glucuronic acid and ex-
creted in the urine. Camphor crosses the placenta.
Uses and Administration
Applied externally, camphor acts as a rubefacient and mild
analgesic and is employed in liniments as a counter-
irritant in fibrositis. neuralgia, and similar conditions. It is
also an ingredient of many inhaled nasal decongestant prepa-
rations but it is of doubtful efficacy. The use of camphor lini-
ment (camphorated oil) is discouraged because of its potential
toxicity. It has been withdrawn from the market in both the
UK and the USA, In the USA the concentration of camphor
in preparations for external use may not exceed 11%.
Taken internally camphor has irritant and carminative proper-
ties and has been used as a mild expectorant. It has also been
used in mixed preparations for cardiovascular disorders.
Camphor-related monoterpene -C been used in
the treatment of urolithiasis, renal disorders, and urinary-
tract infections, and also with menthol in combination with
cheno-deoxycholic acid as adjunct therapy for the dispersal of
bile duct stones.
It has been recommended by the Committee on the Review of
Medicines' that camphor should not be included in products
intended for the treatment of hepatic and biliary disorders.
gallstones, colic, renal disorders, urinary tract infections, or
ureteral stones. The administration of camphor parenterally
or as irrigants was undesirable due to the associated safety
hazard.
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