Phenol
Carbolic Acid
Hydroxybenzene,
Colourless or faintly pink or faintly yellow deliquescent nee-
dle-shaped crystals or crystalline masses, darkening on keep-
ing, with a characteristic odour. USP permits the addition of
a suitable stabilising agent, p.p. not less than 39.5Β°.
Soluble I in 15 of water: very soluble in alcohol, in chloro-
Form, in dichloromethane, in ether, in glycerol, and in fixed
and volatile oils: soluble I in 70 of liquid paraffin. A
solution
of 1 gm in 15 mL water is clear and is neutral or acid to
litmus.
Store in airtight containers. Protect from light. Incompatible
with alkaline salts and nonionic surfactants. The antimicrobi-
al activity of phenol may be diminished through increasing
pH or through combination with blood and other organic mat-
ter.
When phenol is to be mixed with collodion, fixed oils. or par-
affins. melted phenol should be used, and not Liquefied Phe-
nol. (Liquefied Phenol (BP 1998) is an aqueous mixture
containing phenol 77 to 81.5% w/w in purified water. Lique-
fied Phenol (USP 23) contains not less than 89% by weight of
phenol.)
Phenol should not be used to preserve preparations that are to
be freeze-dried.
Adverse Effects
When ingested, phenol causes extensive local corro-
sion. with pain, nausea, vomiting, sweating, and di-
arrhoea. Excitation may occur initially but it is
quickly followed by unconsciousness. There is de-
pression of the CNS, with cardiac arrhythmias, and
circulatory and respiratory failure which may lead to
death. Acidosis may develop and occasionally there
is haemolysis and methaemoglobinaemia with cya-
nosis. The urine may become green. Pulmonary
oedema and myocardial damage may develop, and
damage to the liver and kidneys may lead to organ
failure.
Severe or fatal poisoning may occur from the ab-
sorption of phenol from unbroken skin or wounds
and suitable precautions should be taken to prevent
absorption. Applied to skin, phenol causes blanch-
ing and corrosion, sometimes with little pain. Aque-
ous solutions as dilute as 10% may be corrosive.
Toxic symptoms may also arise through absorption
of phenol vapour by the skin or lungs. Phenol throat
spray may cause local oedema.
Cresols and other phenolic substances have similar
effects.
Effects on the heart. A 10-year-old boy developed life-
threatening premature ventricular complexes during the ap-
plication of a solution of phenol 40% and croton oil 0.8% in
hexachlorophane soap and water for chemical peeling of a
giant hairy naevus. Cardiac arrhythmias have been reported
following the use of phenol for chemical face peeling.- They
were also observed in 3 of 16 children who received phenol
5% as a neurolytic.
Effects on the kidneys. A 41-year-old man developed
acute renal failure due to cutaneous absorption of phenol after
falling into a shallow vat of industrial solvent containing 40%
phenol in dichloromethane. No ingestion occurred. Other
symptoms included 50% body-surface bums, cold extremi-
ties. nausea , vomiting and respiratory distress The patient
required haemodialysis for 3 weeks; some abnormalities of
renal function remained one year later.
Eftects on sexual function. A report' of 3 patients who
developed urinary symptoms and impotence which lasted up
to one year after each receiving phenol 5% in arachis oil
sclerotherapy for haemorrhoids.
Effects on the throat. Acute life-threatening epigloltitis
occurred in a 49-year-old woman following the use of a throat
spray containing the equivalent of 1.4% phenol. The reaction
may have been anaphylactic or due to a direct toxic effect of
the spray. In the UK the Committee on Safety of Medicines'
reported in 1990 that it had received 4 reports (probably in-
eluding the one detailed above) of oedema of the epiglottis
and/or larynx leading lo respiratory difficulties. While the
incidence was rare, the effects were severe; one patient died
and 2 survived only after emergency hospital treatment.
Treatment of Adverse Effects
If phenol has been swallowed, activated charcoal
may be useful. Some sources suggest the cautious
of gastric lavage although this is generally inap-
propriate following ingestion of corrosive substanc-
es.
If phenol has been spilled on the skin removal of
contaminated clothing and excess phenol should be
followed by washing of the skin with copious
amounts of water, then a vegetable oil, Macrogol
300 and eucalyptus oil have also been used.
Contamination of the eyes should be treated by
flooding with water only for at least ten minutes.
The patient should be kept warm and given support-
ive treatment.
Precautions
Solutions containing phenol should not be applied to
large areas of skin or large wounds since sufficient
phenol may be absorbed to give rise to toxic symp-
toms. Phenol should not be used as a throat spray in
patients with epiglottitis. or in children aged under 6
years.
Pharmacokinetics
Phenol is absorbed from the gastro-intestinal tract
and through skin and mucous membranes. It is me-
tabolised to phenylglucuronide and phenyl sulphate.
and small amounts are oxidised to catechol and qui-
nol which are mainly conjugated. The metabolites
are excreted in the urine: on oxidation to quinones
they may tint the urine green.
Uses and Administration
Phenol is an antiseptic and disinfectant effective
against vegetative Gram-positive and Gram-nega-
tive bacteria, mycobacteria and some fungi, but
only very slowly effective against spores. It is also
active against certain viruses. Phenol is more active
in acid solution.
Aqueous solutions up to 1% are bacteriostatic while
stronger solutions are bactericidal.
A 0.5 to 1% solution has been used for its local
anaesthetic effect to relieve itching.
A 1.4% solution is used for pain or irritation of the
mouth and throat. Weak concentrations have also
been used topically for disinfection. A 5% solution
has been used as a disinfectant for excreta.
Oily Phenol Injection (BP 1998), up to 10 mL has
been injected into the tissues around internal haem-
orrhoids as an analgesic sclerosing agent, but alter-
native procedures may be preferred. Aqueous
phenol has also used been as a sclerosant in the treat-
ment of hydroceles.
Solutions of phenol in glycerol have been adminis-
tered intrathecally for the alleviation of spasticity
or injected intrathecally or into soft-tissue
structures for the treatment of chronic low-back
pain. Other types of severe intractable pain may be
relieved by injecting aqueous phenol close to motor
nerves. Aqueous phenol has been used for chemical
sympathectomy in peripheral vascular disorders and
for the treatment of urinary incontinence.
Liquefied phenol has been used in the treatment of
ingrowing toenails.
Chemical face peeling. References of the use of phenol in
chemical face peeling, For a report of adverse cardiac ef-
fects associated with phenol being used for skin peeling, see
effects on the Heart under Adverse Effects, above.
Ingrowing toenail. Liquefied phenol ablation has been per-
formed as an alternative to surgical avulsion in the treatment
of ingrowing toenails. Cauterization with phenol 88% has
also been successfully used to treat ingrowing toenails and
onychogryphosis.
Pain. The neurolytic use of phenol to produce destructive
nerve block has produced variable results, and some
consider the risks and complications outweighs the benefits.
Sclerotherapy. HAEMORRHOIDS. Sclerotherapy with oily
phenol injection has been ,used to treat haemorrhoids. The
technique for preventing mucosal prolapse is to
inject 2 to 5 mL of a 5% solution of phenol in arachis oil into
the submucous space above each of the 3 principal haemor-
rhoids. Rather than causing the hemorrhoidal veins to
thrombose. the injection works by producing sub mucosal fi-
brosis. fixing the mucosa to the underlying muscle. Other
techniques for mucosal fixation such as rubber band ligation
or perhaps infra-red coagulation are more effective and asso-
ciated with fewer complications.
Spasmodic torticollis. Intramuscular phenol was reported
to have produced improvement in 2 patients with moderately
severe spasmodic torticollis who had not responded adequate-
ly to other therapies. Response was maintained by re-injec-
tion every 6 months. For a discussion of the management of
dystonias such as spasmodic torticollis, see under Levodopa.
Urinary incontinence. Although injection of phenol into
the pelvic plexus to produce partial denervation has been used
in the management of severe intractable urge incontinence
its use has been largely abandoned. Some patients,
especially those with detrusor hyperreflexia, have derived
benefit but overall efficacy can be poor and benefits short-
lived.