Salicylate poisoning

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

acute symptomatic poisoning: moderate or severe

1st line – intensive care/high-dependency unit admission plus supportive care

Back

1st line –

intensive care/high-dependency unit admission plus supportive care

There is no antidote for salicylate poisoning.

Manage patients according to symptoms.

In the UK, contact the National Poisons Information Service (NPIS) for advice if clinically indicated or if TOXBASE ^® guidance is unclear.[13]
Discuss any patient with severe clinical features, including coma, convulsions, acute kidney injury, and pulmonary oedema, with the intensive care unit.[7]

In practice, and depending on your experience, escalate for senior review, patients:

With severe clinical features immediately
Who have self-harmed within 1 hour.

In practice, patients with moderate or severe poisoning will need to be managed in an intensive care setting.

Severe poisoning is usually associated with a peak salicylate concentration of >700 mg/L (>5.1 mmol/L). Concentrations >900 mg/L (>6.4 mmol/L) are associated with very severe toxicity.[2]
Moderate poisoning is usually associated with a salicylate concentration of 300 to 700 mg/L (2.2 to 5.1 mmol/L).[2]
See Clinical presentation under Diagnosis recommendations for typical presenting features.

Bear in mind that gastrointestinal tract decontamination is time-sensitive. If the patient presents within 1 hour of ingestion, see Gastrointestinal tract decontamination, below, as soon as the patient is stable.

ABC

Follow ABC resuscitation principles. Maintain a clear Airway and ensure adequate Breathing.[2] Address Circulatory compromise, with vasopressor support if necessary.[1]

Avoid intubation unless there is evidence of respiratory failure (worsening respiratory acidosis, severe hypoxaemia).[2]

Loss of hyperventilatory drive can result in sudden decompensation and death.[2]
Correct hypokalaemia and start urinary alkalinisation prior to intubation if possible.[2]
- In practice, note that intubation is an emergency procedure in salicylate poisoning, whereas correction of hypokalaemia may take hours.
In practice, be vigilant for respiratory failure in patients with chronic salicylate poisoning, because it occurs more commonly in these patients than in acute salicylate toxicity.

Hypokalaemia

Treat hypokalaemia urgently.[2] Replace potassium via intravenous infusion (NOT as a bolus), if necessary, to maintain plasma potassium around 4 to 4.5 mmol/L.[2] Follow local protocols.

This will reduce the risk of severe hypokalaemia that can occur with bicarbonate therapy if this becomes necessary later.[2]

Fluids

Give fluids intravenously (with added potassium if necessary).[2]

Fluid losses may be large.[2]
In practice, patients are often volume-depleted at the time of presentation.

Do not force diuresis because it may cause pulmonary oedema and does not increase renal salicylate excretion.[2]

Acid-base status

Once the patient’s serum potassium concentration is within the normal range, correct metabolic acidosis with intravenous sodium bicarbonate.[2] Follow local protocols.

Administration of sodium bicarbonate reduces transfer of salicylate into the central nervous system and hence reduces toxicity.
Salicylate elimination can be increased by alkalinising the urine.[2]
- Consider urine alkalinisation if the plasma salicylate concentration is >500 mg/L (>3.6 mmol/L) in an adult and >350 mg/L (>2.5 mmol/L) in a child.

Practical tip

Do not use hyperventilation (assisted or unassisted) as a substitute for administration of sodium bicarbonate or haemodialysis.[2]

Convulsions

If the patient is having convulsions:

Give oxygen[2]
Check blood glucose, urea and electrolytes, and arterial blood gas[2]
Correct acid-base and metabolic disturbances as required[2]
Consider checking calcium, magnesium, and phosphate levels.

Control convulsions that are frequent or prolonged with intravenous diazepam, lorazepam, or midazolam.[2] Follow local protocols.

Single brief convulsions do not require treatment.[2]
In practice, most seizures resolve once toxicity has been managed.
Further doses of benzodiazepines may be needed in adults; refer to intensive care.[2]
Seek paediatric consultant input for children who are unresponsive to these measures.[2]

The NPIS in the UK recommends:[2]

Barbiturates as second-line therapy
Avoiding phenytoin.

Pulmonary oedema

Treat pulmonary oedema and/or acute lung injury with continuous positive airway pressure.[2]

In severe cases, treat pulmonary oedema with intermittent positive pressure ventilation and positive end-expiratory pressure.[2]

Psychological support for self-harm

Ensure the patient has access to psychological support if salicylate was taken in the context of self-harm or suicidal intent.[16] Take all patients with suicidal thoughts seriously and respond with compassion and in a timely and proportionate way. See Suicide risk mitigation.

If the patient refuses treatment:

Involve senior support, or contact the appropriate mental health team if in the community.[16][17]

In general, if there is any doubt about a patient’s capacity to make a decision that may limit their life, favour life-saving measures until a more in-depth assessment can be made.

In the community

Refer to secondary care any patient with:[2][6]

Symptoms
A calculated salicylate ingestion ≥125 mg/kg, or any amount of ingested methyl salicylate
Salicylate ingestion with intent to self-harm or attempt suicide.

In remote areas where access to the accident and emergency (A&E) department may be delayed, discuss the patient with the nearest A&E consultant.

Consider – hyperthermia management

Back

Consider –

hyperthermia management

Additional treatment recommended for SOME patients in selected patient group

Treat mild hyperthermia with conventional cooling measures.[2]

Use urgent cooling measures, such as ice-baths and internal cooling devices, if the patient’s body temperature exceeds 39°C (102.2°F).[2]

Use sedation (e.g., with diazepam) cautiously to avoid compromising the patient’s ventilatory drive.[2]
If hyperthermia persists despite these measures, seek advice from your local poisons information service; in the UK, contact the National Poisons Information Service.[2] TOXBASE® (membership required) Opens in new window
Intubation and ventilation is likely to be needed if hyperthermia is not responsive to these measures; discuss urgently with the intensive care team.

Dantrolene may be considered where there is muscular hyperactivity.[2]

It should only be administered by, or under the direct supervision of, a practitioner experienced in the use of dantrolene when used for malignant hyperthermia.

Primary options

diazepam: consult specialist for guidance on dose

Secondary options

dantrolene: consult specialist for guidance on dose

Consider – gastrointestinal tract decontamination

Back

Consider –

gastrointestinal tract decontamination

Additional treatment recommended for SOME patients in selected patient group

Consider giving activated charcoal if the patient presents within 1 hour of ingestion of ≥125 mg/kg salicylate, or any amount of methyl salicylate, providing it is safe to do so and the airway can be protected.[2][6]

Effectiveness declines rapidly with time since ingestion, but later use may show benefit because high doses of salicylate slow gastric emptying and bezoars form when a large number of tablets is ingested.[1][2]
A second dose of charcoal may be indicated if:[2]
- Salicylate preparations are enteric-coated, causing slower absorption[2][7]
- Plasma salicylate concentration continues to rise, suggesting delayed gastric emptying.[2][7]

Practical tip

Aspiration risk, poor gastric motility, and salicylate-induced gastrointestinal haemorrhage are contraindications to the use of activated charcoal.[1]

Do not use ipecac to induce vomiting for salicylate poisoning.[19]

Where practical expertise exists, consider gastric lavage in adults within 1 hour of a potentially life-threatening overdose (suggested dose ≥500 mg/kg salicylate), providing the airway can be protected.[2]

Although recommended and widely used in the UK, the benefit of gastric decontamination is uncertain.[2]

Primary options

activated charcoal: children: 1 g/kg orally as a single dose, maximum 50 g/dose; adults: 50 g orally as a single dose

A second dose may be required if salicylate preparations are enteric-coated, or plasma salicylate concentration continues to rise.[2][7]

Consider – urinary alkalinisation

Back

Consider –

urinary alkalinisation

Additional treatment recommended for SOME patients in selected patient group

If the plasma salicylate concentration is >500 mg/L (>3.6 mmol/L) in an adult, or >350 mg/L (>2.5 mmol/L) in a child, consider urine alkalinisation with intravenous sodium bicarbonate.[2][7] Follow local protocols.

Check the patient’s urinary pH every hour to maintain the urine pH >7.5.[2]

The optimum urine pH is 7.5 to 8.5.[2]

Check the patient’s plasma sodium and potassium every 1 to 2 hours, because dehydration causes increased presentation of sodium to the renal tubules resulting in potassium wasting. Treat hypokalaemia urgently via intravenous infusion (NOT as a bolus) to maintain plasma potassium at around 4 to 4.5 mmol/L.[2] Follow local protocols.

Practical tip

Do not give oral bicarbonate because raising the gastrointestinal luminal pH can cause remaining tablets to dissolve and increase salicylate absorption.[1]

Consider – emergency haemodialysis

Back

Consider –

emergency haemodialysis

Additional treatment recommended for SOME patients in selected patient group

Arrange haemodialysis (or haemodiafiltration) urgently for patients with:[2][7][14]

Salicylate concentration ≥900 mg/L (≥6.4 mmol/L)
Salicylate concentrations >700 mg/L (>5.1 mmol/L) with a metabolic acidosis
Coma due to salicylate poisoning.

Also, consider haemodialysis for patients with a plasma salicylate concentration >700 mg/L (>5.1 mmol/L), severe acidosis, acute kidney injury, congestive cardiac failure, or non-cardiogenic pulmonary oedema.[2]

Patients aged <10 years, or >70 years, are at increased risk of salicylate toxicity and may need dialysis at lower plasma salicylate concentrations.[2]

Discuss a child who requires haemodialysis with your local/regional paediatric intensive care unit.[2]

Practical tip

Haemodialysis/diafiltration is the modality of choice because it removes salicylate and corrects acidosis more rapidly than haemofiltration. In hospitals without dialysis facilities, haemofiltration may be an alternative, particularly if transfer is likely to be delayed.[2]

Do not withhold urine alkalinisation while awaiting haemodialysis, although be careful to avoid volume overload if the patient is oliguric.[2]

acute symptomatic poisoning: mild

1st line – hospital admission plus supportive care

Back

1st line –

hospital admission plus supportive care

There is no antidote for salicylate poisoning.

Admit all patients who are symptomatic.

In practice, and depending on your experience, escalate for senior review patients who have self-harmed within 1 hour.
Consider discharging these patients once they have been asymptomatic for 6 hours and have a normal acid-base balance.[2]

Mild symptomatic poisoning is associated with a peak salicylate concentration of <300 mg/L (<2.2 mmol/L).[2]

See Clinical presentation under Diagnosis recommendations for typical presenting features.

Hypokalaemia

Treat hypokalaemia urgently.[2] Replace potassium via intravenous infusion (NOT as a bolus), if necessary, to maintain plasma potassium around 4 to 4.5 mmol/L.[2] Follow local protocols.

This will reduce the risk of severe hypokalaemia that can occur with bicarbonate therapy if this becomes necessary later.[2]

Fluids

Give fluids intravenously (with added potassium if necessary).[2]

Fluid losses may be large.[2]
In practice, patients are often volume-depleted at the time of presentation.

Do not force diuresis because it may cause pulmonary oedema and does not increase renal salicylate excretion.[2]

Psychological support for self-harm

If the patient refuses treatment:

Involve senior support, or contact the appropriate mental health team if in the community.[16][17]

In general, if there is any doubt about a patient’s capacity to make a decision that may limit their life, favour life-saving measures until a more in-depth assessment can be made.

In the community

Refer to secondary care any patient with:[2][6]

Symptoms
A calculated salicylate ingestion ≥125 mg/kg, or any amount of ingested methyl salicylate
Salicylate ingestion with intent to self-harm or attempt suicide.

In remote areas where access to the accident and emergency (A&E) department may be delayed, discuss the patient with the nearest A&E consultant.

Consider – gastrointestinal tract decontamination

Back

Consider –

gastrointestinal tract decontamination

Additional treatment recommended for SOME patients in selected patient group

Effectiveness declines rapidly with time since ingestion, but later use may show benefit because high doses of salicylate slow gastric emptying and bezoars form when a large number of tablets is ingested.[1][2]
A second dose of charcoal may be indicated if:[2]
- Salicylate preparations are enteric-coated, causing slower absorption[2][7]
- Plasma salicylate concentration continues to rise, suggesting delayed gastric emptying.[2][7]

Practical tip

Aspiration risk, poor gastric motility, and salicylate-induced gastrointestinal haemorrhage are contraindications to the use of activated charcoal.[1]

Do not use ipecac to induce vomiting for salicylate poisoning.[19]

Although recommended and widely used in the UK, the benefit of gastric decontamination is uncertain.[2]

Primary options

activated charcoal: children: 1 g/kg orally as a single dose, maximum 50 g/dose; adults: 50 g orally as a single dose

A second dose may be required if salicylate preparations are enteric-coated, or plasma salicylate concentration continues to rise.[2][7]

acute asymptomatic poisoning: with criteria for hospital referral

1st line – observation plus supportive care

Back

1st line –

observation plus supportive care

There is no antidote for salicylate poisoning.

Assess any asymptomatic patient who might have ingested ≥125 mg/kg salicylate, or any amount of oil of wintergreen (98% methyl salicylate).[1][2][5][6] In practice, this should be in the accident and emergency department.

In the community

Refer to secondary care any patient with:[2][6]

A calculated salicylate ingestion ≥125 mg/kg, or any amount of ingested methyl salicylate
Salicylate ingestion with intent to self-harm or attempt suicide.

In remote areas where access to the accident and emergency (A&E) department may be delayed, discuss the patient with the nearest A&E consultant.

Psychological support for self-harm

Ensure the patient has access to psychological support if salicylate was taken in the context of self-harm or with suicidal intent.[16] Take all patients with suicidal thoughts seriously and respond with compassion and in a timely and proportionate way. See Suicide risk mitigation.

Consider – gastrointestinal tract decontamination

Back

Consider –

gastrointestinal tract decontamination

Additional treatment recommended for SOME patients in selected patient group

Effectiveness declines rapidly with time since ingestion, but later use may show benefit because high doses of salicylate slow gastric emptying and bezoars form when a large number of tablets is ingested.[1][2]
A second dose of charcoal may be indicated if:[2]
- Salicylate preparations are enteric-coated, causing slower absorption[2][7]
- Plasma salicylate concentration continues to rise, suggesting delayed gastric emptying.[2][7]

Practical tip

Aspiration risk, poor gastric motility, and salicylate-induced gastrointestinal haemorrhage are contraindications to the use of activated charcoal.[1]

Do not use ipecac to induce vomiting for salicylate poisoning.[19]

Although recommended and widely used in the UK, the benefit of gastric decontamination is uncertain.[2]

Primary options

activated charcoal: children: 1 g/kg orally as a single dose, maximum 50 g/dose; adults: 50 g orally as a single dose

A second dose may be required if salicylate preparations are enteric-coated, or plasma salicylate concentration continues to rise.[2][7]

Consider – hospital admission or discharge

acute asymptomatic poisoning: without criteria for hospital referral

1st line – observation at home

chronic poisoning

1st line – admission plus supportive care

Back

1st line –

admission plus supportive care

There is no antidote for salicylate poisoning.

In practice:

Patients with chronic poisoning may need to be managed in an intensive care setting
Escalate for senior review within 1 hour patients with chronic salicylate poisoning (depending on your experience)
See Clinical presentation under Diagnosis recommendations for typical presenting features.

Take into account all of the following factors when managing the patient:[1]

The severity of presenting symptoms
The overall clinical condition of the patient
Acid-base status
Serum (or plasma) salicylate level.

Activated charcoal is not indicated unless there is a large ingestion of salicylate within the previous hour, in addition to the chronic salicylate exposure. See Gastrointestinal tract decontamination, below.

ABC

Follow ABC resuscitation principles. Maintain a clear Airway and ensure adequate Breathing.[2] Address Circulatory compromise, with vasopressor support if necessary.[1]

Avoid intubation unless there is evidence of respiratory failure (worsening respiratory acidosis, severe hypoxaemia).[2]

Loss of hyperventilatory drive can result in sudden decompensation and death.[2]
Correct hypokalaemia and start urinary alkalinisation prior to intubation if possible.[2]
- In practice, note that intubation is an emergency procedure in salicylate poisoning, whereas correction of hypokalaemia may take hours.
In practice, be vigilant for respiratory failure in patients with chronic salicylate poisoning, because it occurs more commonly in these patients than in acute salicylate toxicity.

Hypokalaemia

Treat hypokalaemia urgently.[2] Replace potassium via intravenous infusion (NOT as a bolus), if necessary, to maintain plasma potassium around 4 to 4.5 mmol/L.[2] Follow local protocols.

This will reduce the risk of severe hypokalaemia that can occur with bicarbonate therapy if this becomes necessary later.[2]

Fluids

Give fluids intravenously (with added potassium if necessary).[2]

Fluid losses may be large.[2]
In practice, patients are often volume-depleted at the time of presentation.

Do not force diuresis because it may cause pulmonary oedema and does not increase renal salicylate excretion.[2]

Acid-base status

Once the patient’s serum potassium concentration is within the normal range, correct metabolic acidosis with intravenous sodium bicarbonate.[2] Follow local protocols.

Administration of sodium bicarbonate reduces transfer of salicylate into the central nervous system and hence reduces toxicity.
Salicylate elimination can be increased by alkalinising the urine.[2]
- Consider urine alkalinisation if the plasma salicylate concentration is >500 mg/L (>3.6 mmol/L) in an adult and >350 mg/L (>2.5 mmol/L) in a child.

Practical tip

Do not use hyperventilation (assisted or unassisted) as a substitute for administration of sodium bicarbonate or haemodialysis.[2]

Convulsions

If the patient is having convulsions:

Give oxygen[2]
Check blood glucose, urea and electrolytes, and arterial blood gas[2]
Correct acid-base and metabolic disturbances as required[2]
Consider checking calcium, magnesium, and phosphate levels.

Control convulsions that are frequent or prolonged with intravenous diazepam, lorazepam, or midazolam.[2] Follow local protocols.

Single brief convulsions do not require treatment.[2]
In practice, most seizures resolve once toxicity has been managed.
Further doses of benzodiazepines may be needed in adults; refer to intensive care.[2]
Seek paediatric consultant input for children who are unresponsive to these measures.[2]

The National Poisons Information Service in the UK recommends:[2]

Barbiturates as second-line therapy
Avoiding phenytoin.

Pulmonary oedema

Treat pulmonary oedema and/or acute lung injury with continuous positive airway pressure.[2]

In severe cases, treat pulmonary oedema with intermittent positive pressure ventilation and positive end-expiratory pressure.[2]

In the community

Refer to secondary care any patient with:[2]

Chronic salicylate ingestion and non-specific features such as confusion, malaise, and dyspnoea.[2]

Have a high level of suspicion for chronic salicylate intoxication in older adult patients with:[1]

Tachypnoea
Acid-base disturbances (particularly an unexplained respiratory alkalosis)
Non-focal neurological abnormalities
Deterioration in activities of daily living of unknown cause.

Activated charcoal is not indicated unless you suspect an acute (if the patient presents within 1 hour of ingestion) on chronic ingestion. In remote areas where access to the accident and emergency (A&E) department may be delayed, discuss the patient with the nearest A&E consultant.

Consider – hyperthermia management

Back

Consider –

hyperthermia management

Additional treatment recommended for SOME patients in selected patient group

Treat mild hyperthermia with conventional cooling measures.[2]

Use urgent cooling measures, such as ice-baths and internal cooling devices, if the patient’s body temperature exceeds 39°C (102.2°F).[2]

Use sedation (e.g., with diazepam) cautiously to avoid compromising the patient’s ventilatory drive.[2]
If hyperthermia persists despite these measures, seek advice from your local poisons information service; in the UK, contact the National Poisons Information Service.[2] TOXBASE® (membership required) Opens in new window

Dantrolene may be considered where there is muscular hyperactivity.[2]

It should only be administered by, or under the direct supervision of, a practitioner experienced with using dantrolene for malignant hyperthermia.

Primary options

diazepam: consult specialist for guidance on dose

Secondary options

dantrolene: consult specialist for guidance on dose

Consider – gastrointestinal tract decontamination

Back

Consider –

gastrointestinal tract decontamination

Additional treatment recommended for SOME patients in selected patient group

In patients with chronic salicylate poisoning, only consider giving activated charcoal if the patient presents within 1 hour of ingestion of salicylate ingestion in addition to chronic exposure, providing it is safe to do so, and the airway can be protected.

Effectiveness declines rapidly with time since ingestion, but later use may show benefit because high doses of salicylate slow gastric emptying and bezoars form when a large number of tablets is ingested.[1][2]
A second dose of charcoal may be indicated if:[2]
- Salicylate preparations are enteric-coated, causing slower absorption[2][7]
- Plasma salicylate concentration continues to rise, suggesting delayed gastric emptying.[2][7]

Practical tip

Aspiration risk, poor gastric motility, and salicylate-induced gastrointestinal haemorrhage are contraindications to the use of activated charcoal.[1]

Do not use ipecac to induce vomiting for salicylate poisoning.[19]

In practice, only consider gastric lavage in adults within 1 hour of a potentially life-threatening overdose ingested in addition to the chronic salicylate exposure, where practical expertise exists, and providing the airway can be protected.

Although recommended and widely used in the UK, the benefit of gastric decontamination is uncertain.[2]

Primary options

activated charcoal: children: 1 g/kg orally as a single dose, maximum 50 g/dose; adults: 50 g orally as a single dose

A second dose may be required if salicylate preparations are enteric-coated, or plasma salicylate concentration continues to rise.[2][7]

Consider – urinary alkalinisation

Back

Consider –

urinary alkalinisation

Additional treatment recommended for SOME patients in selected patient group

Check the patient’s urinary pH every hour to maintain the urine pH >7.5.[2]

The optimum urine pH is 7.5 to 8.5.[2]

Practical tip

Do not give oral bicarbonate because raising the gastrointestinal luminal pH can cause remaining tablets to dissolve and increase salicylate absorption.[1]

Consider – emergency haemodialysis

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Salicylate poisoning

Treatment algorithm

acute symptomatic poisoning: moderate or severe

intensive care/high-dependency unit admission plus supportive care

ABC

Hypokalaemia

Fluids

Acid-base status

Practical tip

Convulsions

Pulmonary oedema

Psychological support for self-harm

In the community

hyperthermia management

Primary options

Secondary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Secondary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

Secondary options

gastrointestinal tract decontamination

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

urinary alkalinisation

Practical tip

emergency haemodialysis

Practical tip

acute symptomatic poisoning: mild

hospital admission plus supportive care

Hypokalaemia

Fluids

Psychological support for self-harm

In the community

gastrointestinal tract decontamination

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

acute asymptomatic poisoning: with criteria for hospital referral

observation plus supportive care

In the community

Psychological support for self-harm

gastrointestinal tract decontamination

Practical tip

Primary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

hospital admission or discharge

acute asymptomatic poisoning: without criteria for hospital referral

observation at home

chronic poisoning

admission plus supportive care

ABC

Hypokalaemia

Fluids

Acid-base status

Practical tip

Convulsions

Pulmonary oedema

In the community

hyperthermia management

Primary options

Secondary options

These drug options and doses relate to a patient with no comorbidities.

Primary options

Secondary options

Drug choice, dose and interactions may be affected by the patient's comorbidities. Check your local drug formulary.

Primary options

Secondary options

gastrointestinal tract decontamination