What are the gastrointestinal effects of gamma‑butyrolactone (GBL) and its active metabolite gamma‑hydroxybutyrate (GHB)? | Rounds What are the gastrointestinal effects of gamma‑butyrolactone (GBL) and its active metabolite gamma‑hydroxybutyrate (GHB)? | Rounds
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What are the gastrointestinal effects of gamma‑butyrolactone (GBL) and its active metabolite gamma‑hydroxybutyrate (GHB)?

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Gamma-Butyrolactone and Gamma-Hydroxybutyrate Gastrointestinal Effects

GBL is rapidly converted to GHB after oral ingestion and produces the same overall toxidrome, including gastrointestinal upset. [1] Vomiting is a frequently reported gastrointestinal manifestation of GHB/GBL toxicity. [2]

Reported Gastrointestinal Symptoms in GHB/GBL Intoxication

  • Nausea and vomiting are commonly reported features of GHB/GBL toxicity. [2]
  • Vomiting occurred in 71% of GBL-intoxication cases in one CDC report from Minnesota. [2]
  • Nausea/vomiting occurred in 30% of GBL-intoxication cases in one CDC report from Texas. [2]
  • Gastrointestinal upset is described among commonly reported features of GHB/GBL toxicity in clinical toxicology summaries. [3]

Relationship Between GBL and GHB Conversion

GBL is metabolized to GHB in the body. [1] Better absorption of GBL relative to GHB leads to greater bioavailability on an equimolar basis. [1]

Clinical effects of GHB appear dose-related. [1] Vomiting can occur as part of the broader dose-related central nervous system and respiratory depression toxidrome. [1]

Clinical Course of Gastrointestinal Manifestations

Symptoms associated with GBL/GHB intoxication typically resolve with supportive care within 2–96 hours. [1]

Management Implications for Gastrointestinal Effects

Supportive care with close monitoring is the mainstay of management because there is no antidote for GHB. [1] Airway protection and monitoring are prioritized because vomiting may coincide with decreased consciousness and aspiration risk. [4]

Co-Ingestion Factors Affecting Gastrointestinal Presentation

Co-ingestion with alcohol is reported to be common in GHB-related emergency department visits. [4] GBL mixed with ethanol is associated with synergistic central nervous system and respiratory depression in CDC toxicology reporting. [1]

Key Clinical Associations

Vomiting is reported alongside hypotonia, seizures, bradycardia, and respiratory depression in GBL-associated adverse events. [2] Vomiting also appears in broader clinical presentations that include altered mental status and coma in GHB toxicity. [4]

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