Recommendations
Urgent
As with all patients presenting with an acute, severe condition, follow the ABC approach:
Maintain a clear Airway and ensure adequate Breathing[2]
Avoid intubation unless there is evidence of respiratory failure (worsening respiratory acidosis, severe hypoxaemia)[2]
In practice, be vigilant for respiratory failure in patients with chronic salicylate poisoning.
Address Circulatory compromise, initially with intravenous fluid resuscitation, and with vasopressor support if necessary.[1]
Manage patients according to symptoms.
In the UK, contact the National Poisons Information Service for advice if clinically indicated or if TOXBASE ® guidance is unclear.[13] TOXBASE® (membership required) Opens in new window
Discuss any patient with severe clinical features, including coma, convulsions, acute kidney injury, and pulmonary oedema, with the intensive care team.[7]
In practice, and depending on your experience, aim to escalate for senior review patients with:
Severe clinical features immediately
Self-harm within 1 hour
Chronic poisoning within 1 hour.
To manage the salicylate poisoning, 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 associated with 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.[1][2]
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]
A second dose of charcoal may be indicated if:[2]
In a potentially life-threatening overdose in adults (≥500 mg/kg salicylate), consider gastric lavage within 1 hour of ingestion if practical expertise exists for this procedure and providing you can protect the airway.[2]
Treat hypokalaemia and dehydration urgently.[2] Give intravenous fluids, with potassium supplementation as needed.
Once the patient's serum potassium concentration is within the normal range, correct metabolic acidosis with intravenous sodium bicarbonate.[2] Follow local dosing protocols. Administration of sodium bicarbonate reduces transfer of salicylate into the central nervous system and hence reduces toxicity.
Then, if the patient’s plasma salicylate concentration is >500 mg/L (>3.6 mmol/L), consider urine alkalinisation with intravenous sodium bicarbonate.[2][7] In a child, consider urine alkalinisation if plasma salicylate concentration is 350 mg/L (2.5 mmol/L).[2]
Do not withhold urine alkalinisation while awaiting haemodialysis, although be careful to avoid volume overload if the patient is oliguric.[2]
Consider supportive management as necessary:
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.
Key Recommendations
Be aware that clinical deterioration can be rapid.
Patients who are awake and alert may die within 6 hours of presentation.[15]
Patients may die while serum salicylate concentrations are declining because of the increasing volume of distribution with higher salicylate concentrations and acidaemia.[15]
In practice, patients with moderate or severe poisoning will 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]
Do not refer a patient who has accidentally ingested <125 mg/kg salicylate, has not ingested oil of wintergreen, and has no new symptoms since the time of ingestion, for medical assessment (provided the preparation does not contain other agents).[2]
Consider discharging any asymptomatic patient after 6 hours of observation following overdose, provided their plasma salicylate concentration is <300 mg/L (<2.2 mmol/L) and they have normal acid-base status.[2]
Advise patients who are not referred for medical assessment, or who have been discharged after assessment in secondary care, to seek medical attention if symptoms subsequently develop.[2]
There is no antidote for salicylate poisoning. The aim of treatment is to prevent further absorption and increase elimination of the drug in patients with features of moderate or severe poisoning.[7]
Setting of care
In practice, patients with moderate or severe poisoning will be managed in an intensive care or high-dependency setting.
Severe poisoning is usually associated with a peak salicylate concentration of >700 mg/L (>5.1 mmol/L). Concentrations of >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]
In practice, patients with chronic poisoning may need to be managed in an intensive care setting.
Take into account all of the following factors when deciding where to manage the patient:[1]
The severity of presenting symptoms
The overall clinical condition of the patient
Acid-base status
Serum (or plasma) salicylate levels.
In the community
Refer any patient who might have ingested ≥125 mg/kg salicylate or any amount of methyl salicylate, and any patient who is symptomatic, for medical assessment.[2][6] TOXBASE® (membership required) Opens in new window
Do not refer the patient for further medical assessment if the amount accidentally ingested is known to be <125 mg/kg salicylate and the patient has no new symptoms since the time of ingestion (provided the preparation does not contain other agents). Advise these patients to seek medical attention if symptoms develop.
Escalation
Be aware that clinical deterioration can be rapid.
Patients who are awake and alert may die within 6 hours of presentation.[15]
Patients may die while serum salicylate concentrations are declining because of the increasing volume of distribution with higher salicylate concentrations and acidaemia.[15]
In practice, and depending on your experience, aim to escalate for senior review patients with:
Severe clinical features immediately
Self-harm within 1 hour
Chronic poisoning within 1 hour.
Discuss any patient with severe clinical features, including coma, convulsions, acute kidney injury, and pulmonary oedema, with the intensive care unit.[7]
In the UK, contact the National Poisons Information Service for advice if clinically indicated or if TOXBASE ® guidance is unclear. TOXBASE® (membership required) Opens in new window
Ensure the patient has access to psychological support if salicylate was taken with the intention to self-harm.[16] See Suicide risk mitigation.
If the patient refuses treatment:
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.
Monitor vital signs, cardiac rhythm, and capillary blood glucose. In a patient with severe toxicity, or in those being managed in the intensive care unit, check:
Vital signs every 30 minutes
Cardiac rhythm continuously (if cardiac monitoring is available); perform a 12-lead ECG every 4 to 6 hours)
Capillary blood glucose every hour.
Check the patient’s:
Urinary pH every hour; the optimum urine pH is 7.5 to 8.5[2]
Plasma sodium and potassium every 1 to 2 hours. Maintain plasma potassium at around 4 to 4.5 mmol/L.[2]
If the patient is ventilated, monitor arterial blood gas frequently to maintain a pH of 7.5 to 7.6.[2]
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]
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.
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.
Practical tip
Be aware that some patients with chronic salicylate poisoning have a presentation similar to that of sepsis, with persistent hypotension despite fluid resuscitation. In such patients, vasopressor therapy is required for blood-pressure support.[1]
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 your local protocol.
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 dosing 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.[2]
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.
Control convulsions that are frequent or prolonged with intravenous diazepam, lorazepam, or midazolam.[2]
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 (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 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.
If the patient refuses treatment:
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.
Hyperthermia
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 NPIS.[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 using dantrolene for malignant hyperthermia.
In practice, patients with moderate or severe poisoning will be managed in an intensive care or high-dependency 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.
Monitor the patient and provide supportive care as needed. See Monitoring and supportive management above.
Gastrointestinal tract decontamination
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][18]
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]
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]
Urinary alkalinisation
Consider urine alkalinisation with intravenous sodium bicarbonate if:
An adult’s plasma salicylate concentration is >500 mg/L (>3.6 mmol/L)[2][7]
A child’s plasma salicylate concentration is >350 mg/L (>2.5 mmol/L).[2]
Check the patient’s urinary pH every hour.
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]
Haemodialysis
Arrange haemodialysis (or haemodiafiltration) urgently for patients with:[2][7][14][18]
Salicylate concentration ≥900 mg/L (≥6.4 mmol/L)
Salicylate concentration >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][18]
Be aware that 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]
Assess any patient who might have ingested ≥125 mg/kg salicylate or any amount of oil of wintergreen (98% methyl salicylate) and any patient who is symptomatic.[1][2][5][6] In practice, this should be in the accident and emergency department.
See Clinical presentation under Diagnosis recommendations for typical presenting features.
Mild symptomatic poisoning is usually associated with a peak salicylate concentration of <300 mg/L (<2.2 mmol/L).[2]
In practice, and depending on your experience, escalate for senior review within 1 hour patients who have intentionally overdosed to self-harm or attempt suicide.
Monitor the patient and provide supportive care as needed. See Monitoring and supportive management, above.
Gastrointestinal tract decontamination
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][18]
Effectiveness declines rapidly with time since ingestion, but later use may show benefit because high doses of salicylate slow gastric emptying and bezoars form if a large number of tablets is ingested.[1][2]
Although recommended and widely used in the UK, the benefit of gastric decontamination is uncertain.[2]
Assess any 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.
Assess any patient who has ingested salicylates with intent to self-harm or attempt suicide in secondary care and ensure they have access to psychological support.[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 overdose was not intentional, and the patient is asymptomatic, observe the patient for 6 hours after salicylate ingestion in order to identify any developing symptoms and the trend in plasma salicylate levels. Consider admission or discharge depending on salicylate levels and symptoms.
If the patient remains asymptomatic:
Take plasma salicylate levels at least 4 hours after ingestion
Observe the patient for 6 hours after ingestion
Consider discharge for asymptomatic patients with normal acid-base status after observation for 6 hours following the overdose, provided their plasma salicylate concentration is <300 mg/L (<2.2 mmol/L)
Depending on the timing of presentation, symptomatology, and blood tests, in practice, a single salicylate concentration <300 mg/L (<2.2 mmol/L) should suffice in an asymptomatic patient after 6 hours.
If the patient develops symptoms:
Admit them to hospital
Take plasma salicylate levels at least 2 hours after ingestion and other tests as detailed in Investigations
Depending on salicylate concentrations and symptoms, refer to the relevant patient group in this section for detailed management recommendations.
Monitor the patient and provide supportive care as needed. See Monitoring and supportive management above.
Gastrointestinal tract decontamination
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 if a large number of tablets is ingested.[1][2]
A second dose of charcoal may be indicated if:[2]
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]
Do not refer for medical assessment a patient who has accidentally ingested <125 mg/kg salicylate, has not ingested oil of wintergreen (98% methyl salicylate), and has no new symptoms since the time of ingestion (provided the preparation does not contain other agents).[2][6]
Advise patients to seek medical attention if symptoms develop.[2]
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 levels.
In practice:
Have a lower threshold for arranging haemodialysis in patients with chronic overdose
Take into account significant renal impairment when making decisions about the need for haemodialysis
Activated charcoal is not indicated unless there is a large ingestion of salicylate within the previous hour, in addition to the chronic salicylate exposure
Consider urinary alkalinisation.
Monitor the patient and provide supportive care as needed.
See Monitoring and supportive management, above.
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