Drug interactions
Promethazine + Sodium oxybate
Severity: Major
Promethazine and Sodium oxybate: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Sodium oxybate is a potent CNS depressant, and promethazine adds sedative antihistamine and phenothiazine effects. Concurrent use can cause profound sedation, respiratory depression, coma and death.
What this interaction means in plain words
Promethazine and Sodium oxybate can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Promethazine belongs to Respiratory; Sodium oxybate belongs to Central Nervous System.
Why it happens
Additive CNS and respiratory depression from GABA-B and GHB receptor effects with H1 antagonism.
What to do
Avoid the combination if alternatives exist. If it is necessary, use the lowest doses for the shortest time and monitor for sedation and respiratory depression.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Other interactions of Sodium oxybate
- Alprazolam + Sodium oxybate Contraindicated
- Amobarbital + Sodium oxybate Contraindicated
- Butorphanol + Sodium oxybate Contraindicated
- Chloral hydrate + Sodium oxybate Contraindicated
- Clonazepam + Sodium oxybate Contraindicated
- Clorazepate + Sodium oxybate Contraindicated
Frequently asked questions
Can I take Promethazine with Sodium oxybate?
MediHelp rates the interaction as major. Promethazine and Sodium oxybate can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Sodium oxybate is a potent CNS depressant, and promethazine adds sedative antihistamine and phenothiazine effects. Concurrent use can cause profound sedation, respiratory depression, coma and death.
How serious is the interaction between Promethazine and Sodium oxybate?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if alternatives exist. If it is necessary, use the lowest doses for the shortest time and monitor for sedation and respiratory depression.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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