What are the laboratory findings in a sertraline (selective serotonin reuptake inhibitor) overdose?

From the Guidelines

Laboratory findings in a sertraline overdose typically include hyponatremia, elevated liver enzymes, prolonged QT interval, and serotonin syndrome markers such as elevated creatine kinase levels. These findings can vary based on the severity of the overdose, with mild to moderate cases often showing minimal laboratory abnormalities 1. Some key laboratory findings to consider include:

• Hyponatremia, which occurs due to SIADH (syndrome of inappropriate antidiuretic hormone secretion)
• Elevated liver enzymes (AST, ALT)
• Prolonged QT interval on ECG, resulting from the drug's effect on cardiac ion channels
• Serotonin syndrome markers, including elevated creatine kinase (CK) levels, indicating muscle breakdown associated with serotonin syndrome
• Metabolic acidosis, which may be revealed through blood tests
• Leukocytosis, which may be shown through complete blood counts
• Coagulation studies, which may show abnormalities in severe cases It is essential to accompany laboratory monitoring with clinical assessment for serotonin syndrome symptoms, including mental status changes, neuromuscular abnormalities, and autonomic instability 1. Sertraline levels themselves are not routinely measured in clinical practice, but monitoring for symptoms and laboratory findings is crucial for managing the overdose effectively 1.

From the FDA Drug Label

False-positive urine immunoassay screening tests for benzodiazepines have been reported in patients taking sertraline. This is due to lack of specificity of the screening tests. False-positive test results may be expected for several days following discontinuation of sertraline therapy Confirmatory tests, such as gas chromatography/mass spectrometry, will distinguish sertraline from benzodiazepines.

The laboratory findings in a sertraline overdose may include false-positive urine immunoassay screening tests for benzodiazepines. It is recommended to use confirmatory tests, such as gas chromatography/mass spectrometry, to distinguish sertraline from benzodiazepines 2.

• Key laboratory findings:
  • False-positive urine immunoassay screening tests for benzodiazepines
  • Confirmatory tests, such as gas chromatography/mass spectrometry, can distinguish sertraline from benzodiazepines Note that the provided drug label does not explicitly describe the laboratory findings of a sertraline overdose, but it does mention the potential for false-positive test results.

From the Research

Laboratory Findings in Sertraline Overdose

Laboratory findings in sertraline overdose may include:

• Elevated serum sertraline concentration, as reported in a case of massive sertraline overdose 3
• Elevated creatine kinase levels, indicating potential muscle damage or rhabdomyolysis, as seen in cases of serotonin syndrome 4, 3
• Abnormal liver function tests, although not specifically mentioned in the provided studies
• Electrocardiogram (ECG) changes, such as QT prolongation, which may increase the risk of arrhythmias, as discussed in the context of sertraline use in patients with post-myocardial infarction depression 5
• Blood gas analysis, which may show acidosis or other abnormalities in severe cases

Autopsy and Toxicology Findings

In cases of fatal sertraline overdose, autopsy and toxicology findings may include:

• Elevated sertraline and N-desmethylsertraline concentrations in peripheral blood, as reported in a case of fatal multiple drug intoxication 6
• Presence of other drugs or substances, which may have contributed to the fatal outcome, as seen in cases of multiple drug overdose 6

Biochemical Markers

Biochemical markers, such as:

• Serum serotonin levels, which may be elevated in cases of serotonin syndrome 4, 7
• Other markers of muscle damage, such as myoglobin or troponin, which may be elevated in cases of rhabdomyolysis 4