anaesthetics, such as tetracaine; reactions are less
frequent with the amide types, such as articaine,
bupivacaine, levobupivacaine, lidocaine, mepivacaine,
prilocaine, and ropivacaine. Cross-sensitivity reactions
may be avoided by using the alternative chemical type.
l PREGNANCY Not known to be harmful. Do not use for
paracervical block in obstetrics.
l BREAST FEEDING Not known to be harmful.
l HEPATIC IMPAIRMENT Manufacturer advises caution in
Dose adjustments Manufacturer advises consider dose
reduction for repeat doses in severe impairment.
l RENAL IMPAIRMENT Caution in severe impairment.
Increased risk of systemic toxicity in chronic renal failure.
l MEDICINAL FORMS There can be variation in the licensing of
different medicines containing the same drug.
ELECTROLYTES: May contain Sodium
▶ Ropivacaine hydrochloride (Non-proprietary)
Ropivacaine hydrochloride 2 mg per 1 ml Ropivacaine 20mg/10ml
solution for injection ampoules | 10 ampoule P £16.50 (Hospital
Ropivacaine hydrochloride 7.5 mg per 1 ml Ropivacaine
75mg/10ml solution for injection ampoules | 10 ampoule P £25.00 (Hospital only)
Ropivacaine hydrochloride 10 mg per 1 ml Ropivacaine
100mg/10ml solution for injection ampoules | 10 ampoule P £30.00 (Hospital only)
▶ Naropin (Aspen Pharma Trading Ltd)
Ropivacaine hydrochloride 2 mg per 1 ml Naropin 20mg/10ml
solution for injection ampoules | 5 ampoule P £12.79
Ropivacaine hydrochloride 7.5 mg per 1 ml Naropin 75mg/10ml
solution for injection ampoules | 5 ampoule P £15.90
Ropivacaine hydrochloride 10 mg per 1 ml Naropin 100mg/10ml
solution for injection ampoules | 5 ampoule P £19.22
ELECTROLYTES: May contain Sodium
▶ Ropivacaine hydrochloride (Non-proprietary)
Ropivacaine hydrochloride 2 mg per 1 ml Ropivacaine
400mg/200ml infusion bags | 5 bag P £75.55 (Hospital only) | 10 bag P £137.00 (Hospital only)
▶ Naropin (Aspen Pharma Trading Ltd)
Ropivacaine hydrochloride 2 mg per 1 ml Naropin 400mg/200ml
infusion Polybags | 5 bag P £86.70
Anaesthesia before venepuncture or venous cannulation
▶ Child 1 month–4 years: Apply contents of up to 1 tube
(applied at separate sites at a single time or appropriate
proportion) to site of venepuncture or venous
cannulation and cover with occlusive dressing; remove
gel and dressing after 30 minutes for venepuncture and
after 45 minutes for venous cannulation
▶ Child 5–17 years: Apply contents of up to 5 tubes
(applied at separate sites at a single time or appropriate
proportion) to site of venepuncture or venous
cannulation and cover with occlusive dressing; remove
gel and dressing after 30 minutes for venepuncture and
after 45 minutes for venous cannulation
▶ Adult: Apply contents of up to 5 tubes (applied at
separate sites at a single time or appropriate
proportion) to site of venepuncture or venous
cannulation and cover with occlusive dressing; remove
gel and dressing after 30 minutes for venepuncture and
after 45 minutes for venous cannulation
l CONTRA-INDICATIONS Should not be applied to damaged
l INTERACTIONS → Appendix 1: anaesthetics, local
l SIDE-EFFECTS Oedema . skin reactions
SIDE-EFFECTS, FURTHER INFORMATION The systemic
toxicity of local anaesthetics mainly involves the central
nervous system; systemic side effects unlikely as minimal
absorption following topical application.
l ALLERGY AND CROSS-SENSITIVITY
▶ Hypersensitivity and cross-sensitivity Hypersensitivity
reactions occur mainly with the ester-type local
anaesthetics, such as tetracaine; reactions are less
frequent with the amide types, such as articaine,
bupivacaine, levobupivacaine, lidocaine, mepivacaine,
prilocaine, and ropivacaine. Cross-sensitivity reactions
may be avoided by using the alternative chemical type.
l BREAST FEEDING Not known to be harmful.
Medicines for Children leaflet: Tetracaine gel for local anaesthesia
www.medicinesforchildren.org.uk/tetracaine-gel-localanaesthesia
l MEDICINAL FORMS There can be variation in the licensing of
different medicines containing the same drug.
EXCIPIENTS: May contain Hydroxybenzoates (parabens)
▶ Ametop (Forum Health Products Ltd)
Tetracaine 40 mg per 1 gram Ametop 4% gel | 1.5 gram p £1.08
Emergency treatment of poisoning
1 Active elimination from the gastrointestinal tract
2.2 Organophosphorus toxicity 1367
3.1 Benzodiazepine toxicity 1368
3.2 Digoxin toxicity page 1368
Poisoning, emergency treatment
These notes provide only an overview of the treatment of
poisoning, and it is strongly recommended that either
TOXBASE or the UK National Poisons Information
Service be consulted when there is doubt about the degree
Patients who have features of poisoning should generally be
admitted to hospital. Patients who have taken poisons with
delayed action should also be admitted, even if they appear
well. Delayed-action poisons include aspirin p. 121, iron,
the effects of modified-release preparations are also delayed.
A note of all relevant information, including what treatment
has been given, should accompany the patient to hospital.
TOXBASE, the primary clinical toxicology database of the
National Poisons Information Service, is available on the
internet to registered users at www.toxbase.org (a backup site
is available at www.toxbasebackup.org if the main site cannot
be accessed). It provides information about routine
diagnosis, treatment, and management of patients exposed
to drugs, household products, and industrial and agricultural
Specialist information and advice on the treatment of
poisoning is available day and night from the UK National
Poisons Information Service on the following number: Tel:
Advice on laboratory analytical services can be obtained
from TOXBASE or from the National Poisons Information
Service. Help with identifying capsules or tablets may be
available from a regional medicines information centre or
from the National Poisons Information Service (out of
It is often impossible to establish with certainty the identity
of the poison and the size of the dose. This is not usually
important because only a few poisons (such as opioids,
paracetamol, and iron) have specific antidotes; few patients
require active removal of the poison. In most patients,
treatment is directed at managing symptoms as they arise.
Nevertheless, knowledge of the type and timing of poisoning
can help in anticipating the course of events. All relevant
information should be sought from the poisoned individual
and from carers or parents. However, such information
should be interpreted with care because it may not be
complete or entirely reliable. Sometimes symptoms arise
from other illnesses and patients should be assessed
carefully. Accidents may involve domestic and industrial
products (the contents of which are not generally known).
The National Poisons Information Service should be
consulted when there is doubt about any aspect of suspected
Respiration is often impaired in unconscious patients. An
obstructed airway requires immediate attention. In the
absence of trauma, the airway should be opened with simple
measures such as chin lift or jaw thrust. An oropharyngeal or
nasopharyngeal airway may be useful in patients with
reduced consciousness to prevent obstruction, provided
ventilation is adequate. Intubation and ventilation should be
considered in patients whose airway cannot be protected or
who have respiratory acidosis because of inadequate
ventilation; such patients should be monitored in a critical
Most poisons that impair consciousness also depress
respiration. Assisted ventilation (either mouth-to-mouth or
using a bag-valve-mask device) may be needed. Oxygen is
not a substitute for adequate ventilation, although it should
be given in the highest concentration possible in poisoning
with carbon monoxide and irritant gases.
Hypotension is common in severe poisoning with central
nervous system depressants. A systolic blood pressure of less
than 70 mmHg may lead to irreversible brain damage or renal
tubular necrosis. Hypotension should be corrected initially
by raising the foot of the bed and administration of an
infusion of either sodium chloride p. 1040 or a colloid.
Vasoconstrictor sympathomimetics are rarely required and
their use may be discussed with the National Poisons
Fluid depletion without hypotension is common after
prolonged coma and after aspirin poisoning due to vomiting,
Hypertension, often transient, occurs less frequently than
hypotension in poisoning; it may be associated with
sympathomimetic drugs such as amfetamines,
Cardiac conduction defects and arrhythmias can occur in
acute poisoning, notably with tricyclic antidepressants,
some antipsychotics, and some antihistamines. Arrhythmias
often respond to correction of underlying hypoxia, acidosis,
BNF 78 Emergency treatment of poisoning 1359
Emergency treatment of poisoning
or other biochemical abnormalities, but ventricular
arrhythmias that cause serious hypotension require
treatment. If the QT interval is prolonged, specialist advice
should be sought because the use of some anti-arrhythmic
drugs may be inappropriate. Supraventricular arrhythmias
are seldom life-threatening and drug treatment is best
withheld until the patient reaches hospital.
Hypothermia may develop in patients of any age who have
been deeply unconscious for some hours, particularly
following overdose with barbiturates or phenothiazines. It
may be missed unless core temperature is measured using a
low-reading rectal thermometer or by some other means.
Hypothermia should be managed by prevention of further
heat loss and appropriate re-warming as clinically indicated.
Hyperthermia can develop in patients taking CNS
stimulants; children and the elderly are also at risk when
taking therapeutic doses of drugs with antimuscarinic
properties. Hyperthermia is initially managed by removing
all unnecessary clothing and using a fan. Sponging with
tepid water will promote evaporation. Advice should be
sought from the National Poisons Information Service on the
management of severe hyperthermia resulting from
conditions such as the serotonin syndrome.
Both hypothermia and hyperthermia require urgent
hospitalisation for assessment and supportive treatment.
Single short-lived convulsions (lasting less than 5 minutes)
do not require treatment. If convulsions are protracted or
recur frequently, lorazepam p. 339 or diazepam p. 343
(preferably as emulsion) should be given by slow intravenous
injection into a large vein. Benzodiazepines should not be
given by the intramuscular route for convulsions. If the
intravenous route is not readily available, midazolam
oromucosal solution p. 340 [unlicensed use in adults and
children under 3 months] can be given by the buccal route or
diazepam can be administered as a rectal solution.
Drug- or chemical-induced methaemoglobinaemia should be
treated with methylthioninium chloride p. 1371 if the
methaemoglobin concentration is 30% or higher, or if
symptoms of tissue hypoxia are present despite oxygen
therapy. Methylthioninium chloride reduces the ferric iron
of methaemoglobin back to the ferrous iron of haemoglobin;
in high doses, methylthioninium chloride can itself cause
Poison removal and elimination
Given by mouth, charcoal, activated p. 1366 can bind many
poisons in the gastro-intestinal system, thereby reducing
their absorption. The sooner it is given the more effective it
is, but it may still be effective up to 1 hour after ingestion of
the poison—longer in the case of modified-release
preparations or of drugs with antimuscarinic
(anticholinergic) properties. It is particularly useful for the
prevention of absorption of poisons that are toxic in small
amounts, such as antidepressants.
Repeated doses of charcoal, activated by mouth enhance the
elimination of some drugs after they have been absorbed;
repeated doses are given after overdosage with:
If vomiting occurs after dosing it should be treated (e.g.
with an antiemetic drug) since it may reduce the efficacy of
charcoal treatment. In cases of intolerance, the dose may be
reduced and the frequency increased but this may
Charcoal, activated should not be used for poisoning with
petroleum distillates, corrosive substances, alcohols,
malathion, cyanides and metal salts including iron and
Other techniques intended to enhance the elimination of
poisons after absorption are only practicable in hospital and
are only suitable for a small number of severely poisoned
patients. Moreover, they only apply to a limited number of
. haemodialysis for ethylene glycol, lithium, methanol,
phenobarbital, salicylates, and sodium valproate;
. alkalinisation of the urine for salicylates.
Removal from the gastro-intestinal tract
Gastric lavage is rarely required; for substances that cannot
be removed effectively by other means (e.g. iron), it should
be considered only if a life-threatening amount has been
ingested within the previous hour. It should be carried out
only if the airway can be protected adequately. Gastric lavage
is contra-indicated if a corrosive substance or a petroleum
distillate has been ingested, but it may occasionally be
considered in patients who have ingested drugs that are not
adsorbed by charcoal, such as iron or lithium. Induction of
emesis (e.g. with ipecacuanha) is not recommended because
there is no evidence that it affects absorption and it may
increase the risk of aspiration.
Whole bowel irrigation (by means of a bowel cleansing
preparation) has been used in poisoning with certain
modified-release or enteric-coated formulations, in severe
poisoning with iron and lithium salts, and if illicit drugs are
carried in the gastro-intestinal tract (‘body-packing’).
However, it is not clear that the procedure improves
outcome and advice should be sought from the National
Acute intoxication with alcohol (ethanol) is common in
adults but also occurs in children. The features include
ataxia, dysarthria, nystagmus, and drowsiness, which may
progress to coma, with hypotension and acidosis. Aspiration
of vomit is a special hazard and hypoglycaemia may occur in
children and some adults. Patients are managed
supportively, with particular attention to maintaining a clear
airway and measures to reduce the risk of aspiration of
gastric contents. The blood glucose is measured and glucose
The main features of salicylate poisoning are
hyperventilation, tinnitus, deafness, vasodilatation, and
sweating. Coma is uncommon but indicates very severe
poisoning. The associated acid-base disturbances are
Treatment must be in hospital, where plasma salicylate,
pH, and electrolytes can be measured; absorption of aspirin
may be slow and the plasma-salicylate concentration may
continue to rise for several hours, requiring repeated
measurement. Plasma-salicylate concentration may not
correlate with clinical severity in the young and the elderly,
and clinical and biochemical assessment is necessary.
Generally, the clinical severity of poisoning is less below a
plasma-salicylate concentration of 500 mg/litre
(3.6 mmol/litre), unless there is evidence of metabolic
acidosis. Activated charcoal can be given within 1 hour of
ingesting more than 125 mg/kg of aspirin. Fluid losses should
be replaced and intravenous sodium bicarbonate may be
given (ensuring plasma-potassium concentration is within
the reference range) to enhance urinary salicylate excretion
1360 Emergency treatment of poisoning BNF 78
Emergency treatment of poisoning
Plasma-potassium concentration should be corrected before
giving sodium bicarbonate as hypokalaemia may complicate
Haemodialysis is the treatment of choice for severe
salicylate poisoning and should be considered when the
plasma-salicylate concentration exceeds 700 mg/litre
(5.1 mmol/litre) or in the presence of severe metabolic
Opioids (narcotic analgesics) cause coma, respiratory
depression, and pinpoint pupils. The specific antidote
naloxone hydrochloride p. 1369 is indicated if there is coma
or bradypnoea. Since naloxone has a shorter duration of
action than many opioids, close monitoring and repeated
injections are necessary according to the respiratory rate and
depth of coma. When repeated administration of naloxone is
required, it can be given by continuous intravenous infusion
instead and the rate of infusion adjusted according to vital
signs. The effects of some opioids, such as buprenorphine,
are only partially reversed by naloxone.
Dextropropoxyphene and methadone have very long
durations of action; patients may need to be monitored for
long periods following large overdoses.
Naloxone reverses the opioid effects of
dextropropoxyphene. The long duration of action of
dextropropoxyphene calls for prolonged monitoring and
further doses of naloxone may be required.
Norpropoxyphene, a metabolite of dextropropoxyphene,
also has cardiotoxic effects which may require treatment
with sodium bicarbonate p. 1038 or magnesium sulfate
p. 1051, or both. Arrhythmias may occur for up to 12 hours.
In cases of intravenous paracetamol poisoning contact
the National Poisons Information Service for advice on risk
Toxic doses of paracetamol p. 444 may cause severe
hepatocellular necrosis and, much less frequently, renal
tubular necrosis. Nausea and vomiting, the only early
features of poisoning, usually settle within 24 hours.
Persistence beyond this time, often associated with the
onset of right subcostal pain and tenderness, usually
indicates development of hepatic necrosis. Liver damage is
maximal 3–4 days after paracetamol overdose and may lead
to encephalopathy, haemorrhage, hypoglycaemia, cerebral
oedema, and death. Therefore, despite a lack of significant
early symptoms, patients who have taken an overdose of
paracetamol should be transferred to hospital urgently.
To avoid underestimating the potentially toxic
paracetamol dose ingested by obese patients who weigh
more than 110 kg, use a body-weight of 110 kg (rather than
their actual body-weight) when calculating the total dose of
paracetamol ingested (in mg/kg).
Acetylcysteine p. 1370 protects the liver if infused up to,
and possibly beyond, 24 hours of ingesting paracetamol. It is
most effective if given within 8 hours of ingestion, after
which effectiveness declines. Very rarely, giving
acetylcysteine p. 1370 by mouth [unlicensed route] is an
alternative if intravenous access is not possible—contact the
National Poisons Information Service for advice.
Paracetamol overdose treatment graph
BNF 78 Emergency treatment of poisoning 1361
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