Thiopental
Limited data
Limited data
Sparse data. Doses and effects may be unreliable or untested.
- 2 corroborating sources
- duration data present
- PubChem toxicity data
- 2 corroborating sources
- duration data present
- PubChem toxicity data
Aliases: Pentothal, Thiopentone, Penthiobarbital, Sodium pentothal, Sodium thiopental
Summary
Thiopental is an ultra-short-acting barbiturate used primarily for anesthesia induction, rapid sedation, emergency seizure control, and reducing intracranial pressure. It must be administered intravenously by trained medical professionals. The drug's brief duration of action results from rapid redistribution to fat and muscle tissue rather than metabolism.
Dose Information
| ROA | Threshold |
|---|---|
| Intravenous | <50mg |
Only a threshold dose is documented for this substance — the smallest amount with a noticeable effect. There is no published light/common/strong ladder to show above it.
Sources
Intravenous
Dose ladder — DrugsPROOnset, Duration & After-effects
| ROA | Onset | Comeup | Peak | Offset | Total |
|---|---|---|---|---|---|
| Intravenous | 36 sec | 1 min | 1-2 min | 5-15 min | 8-19 min |
Tolerance
No tolerance chart. Our decay curves for these drugs were estimates, and a curve can make tolerance look longer-lasting than it is, which is the dangerous direction.
How fast tolerance to these drugs fades after a break has not been measured well enough to draw, so don't count on a dose you used to take still being safe: after time off, start with a much smaller amount and don't use alone. Mixing sedatives with each other, with alcohol or with opioids sharply raises the risk of a fatal overdose. If you've been using regularly, don't stop suddenly: withdrawal from benzodiazepines, alcohol or GHB/GBL can cause seizures or delirium, so get medical help to cut down gradually. With barbiturates, you get used to the effects much more than to a dangerous dose, so the gap between a dose that works and one that kills shrinks the more you use. Stopping suddenly after regular use can cause convulsions and delirium.
Sources: FRANK: benzodiazepines · Alcohol and Drug Foundation: GHB · FDA 2020: benzodiazepine boxed warning · FDA 2019: gabapentinoids and breathing · NHS: alcohol use disorder · Phenobarbital label: drug abuse and dependence
Cross-Tolerances
Effects
Effect glossary — · full glossary
Helpful Links
Add to PsychonautWiki Journal
The PsychonautWiki Journal logging app doesn't include every substance. To track Thiopental there, start adding an ingestion, search for the name, and choose to add it as a custom substance. Paste these values:
Thiopental Source: SubstanceSearch (substancesearch.com) Intravenous dose (mg): threshold <50 Intravenous duration: onset 36s · come-up 1m · peak 1-2m · offset 5-15m · total 8-19m · after-effects 2-6h Note: ranges are harm-reduction guidance, not a prescription. Start low, go slow, and test your substances.
The app keeps custom substances simple, so the full dose ranges live in the description text above. Ranges are harm-reduction guidance, not a prescription.
Report an issue or suggest an edit
Spotted incorrect or dangerous information, have a correction, a new study, or a useful addition for Thiopental? Let us know. Reports are reviewed by moderators — this is not posted publicly.