Ten Years of Robotripping: Evidence of Tolerance to Dextromethorphan Hydrobromide in a Long-Term User.

We report a patient with persistent dextromethorphan hydrobromide abuse at escalating doses whose mean serum chloride concentration increased, on average, by 0.00232 mEq/L every day over a 110-month period. This case demonstrates progressive spurious hyperchloremia secondary to bromide interference in hospital-based chloride assays, supporting the patient's reported need to dose escalate to the same desired effect. Although this artefactual laboratory finding is a well-documented result of bromide ingestion, it may be useful in identifying patterns of dextromethorphan hydrobromide use that suggest tolerance.