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Death may occur when GABAergic substances are combined with other depressants such as opiates, benzodiazepines, barbiturates, gabapentinoids, thienodiazepines or alcohol.[1]

It is strongly discouraged to combine these substances, particularly in common to heavy doses.


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Summary sheet: Carisoprodol
Chemical Nomenclature
Common names Carisoprodol, Soma
Substitutive name Isopropyl meprobamate
Systematic name [2-(Carbamoyloxymethyl)-2-methylpentyl] N-propan-2-ylcarbamate
Class Membership
Psychoactive class Depressant
Chemical class Carbamate
Routes of Administration

WARNING: Always start with lower doses due to differences between individual body weight, tolerance, metabolism, and personal sensitivity. See responsible use section.

Threshold 50 - 100 mg
Light 100 - 325 mg
Common 325 - 500 mg
Strong 500 - 750 mg
Heavy 750 mg +
Onset 15 - 60 minutes
Peak 2 - 5 hours
After effects 1 - 12 hours

DISCLAIMER: PW's dosage information is gathered from users and resources for educational purposes only. It is not a recommendation and should be verified with other sources for accuracy.

Carisoprodol, also known by the brand name Soma, is a carbamate sedative-hypnotic. Carisoprodol is used medically as a centrally-acting muscle relaxant, anxiolytic and hypnotic for the short-term treatment of insomnia. Carisoprodol also has weak analgesic effects. Carisoprodol is sometimes found in formulations also containing caffeine and acetaminophen. Carisoprodol produces similar effects to barbiturates. Carisoprodol acts as a prodrug to meprobamate, meaning it is metabolized to meprobamate when it enters the body.

Carisoprodol, like barbiturates, has been primarily replaced by benzodiazepines due to a larger therapeutic window, having less severe adverse effects and being safer in overdose.


Chemically, carisoprodol is classified as a carbamate. It is extremely similar in structure to meprobamate, the only difference being an isopropyl group bonded to an amine group. Carbamates are derivatives of carbamic acid. The empirical formula is carisoprodol is C12H24N2O4 and has a molar mass of 260.33 grams per mole.


Carisoprodol is a prodrug that is metabolized to meprobamate. The precise mechanism of meprobamate is not completely understood. However it is believed that meprobamate acts similarly to benzodiazepines and barbiturates, acting as a positive allosteric modulator of a GABAA receptor[2]. Unlike barbiturates and benzodiazepines, in animal studies meprobamate has been shown to retain most of its effects without having gamma-aminobutyric acid present[2]. Meprobamate has also been noted to be an adenosine reuptake inhibitor, making it unique among hypnotics[3].

Carisoprodol is metabolized by the cytochrome P450 2C19 enzyme in the liver and has a biological half-life of about two hours. Carisoprodol and its metabolites are excreted by the kidneys in urine.

Carisoprodol is a prodrug to meprobamate (pictured).

Subjective effects

The effects listed below are based upon the subjective effects index and personal experiences of PsychonautWiki contributors. These effects should be taken with a grain of salt and will rarely (if ever) occur all at once, but heavier doses will increase the chances of inducing a full range of effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.

Physical effects

Visual effects

Cognitive effects

Toxicity and harm potential

Carisoprodol likely has moderate toxicity relative to dose. However, carisoprodol is potentially lethal when mixed with depressants like alcohol or opioids. Carisoprodol has been taken off the market is several countries such as Sweden and Indonesia due to side effects and abuse.

It is strongly recommended that one use harm reduction practices when using this drug.

Tolerance and addiction potential

Carisoprodol is extremely physically and psychologically addictive. Carbamate withdrawal, like barbiturate withdrawal, is medically serious and can potentially cause a life-threatening withdrawal syndrome that can cause seizures, psychosis, and death. Drugs which lower the seizure threshold such as tramadol and amphetamine should be avoided during withdrawal.

Tolerance will develop to the sedative-hypnotic effects of carisoprodol after prolonged use. It is unknown exactly how long it takes for tolerance to reach baseline.

Dangerous interactions

Although many drugs are safe on their own, they can become dangerous and even life-threatening when combined with other substances. The list below contains some common potentially dangerous combinations, but may not include all of them. Certain combinations may be harmless in low doses of each but still, increase the potential risk of death. Independent research should always be done to ensure that a combination of two or more substances is safe before consumption.

  • Depressants (1,4-Butanediol, 2-methyl-2-butanol, alcohol, barbiturates, GHB/GBL, methaqualone, opioids) - This combination can result in dangerous or even fatal levels of respiratory depression. These substances potentiate the muscle relaxation, sedation and amnesia caused by one another and can lead to unexpected loss of consciousness at high doses. There is also an increased risk of vomiting during unconsciousness and death from the resulting suffocation. If this occurs, users should try to fall asleep in the recovery position or have a friend move them into it. Carisoprodol is deemed to have an increased incidence of serious adverse effects when used concurrently with other depressants than other depressants.
  • Dissociatives - This combination can lead to an increased risk of vomiting during unconsciousness and death from the resulting suffocation. If this occurs, users should attempt to fall asleep in the recovery position or have a friend move them into it.
  • Stimulants - It is unsafe to combine carbamates with stimulants due to the risk of excessive intoxication. Stimulants decrease the sedative effect of carbamates, which is the main factor most people consider when determining their level of intoxication. Once the stimulant wears off, the effects of carbamates will be considerably increased, leading to intensified disinhibition as well as other effects. If combined, one should strictly limit themselves to only dosing a certain amount of carbamates per hour. This combination can also potentially result in severe dehydration if hydration is not monitored.

Legal issues

In most jurisdictions, carisoprodol is considered a prescription-only and/or controlled drug.

  • United States: In the United States, carisoprodol is a Schedule IV Controlled Substance[4]. Therefore, it is prescription-only and anyone caught in possession of the substance with or without intent to distribute is punishable by law.

External links


  1. Risks of Combining Depressants (Tripsit) |
  2. 2.0 2.1 Barbiturate-Like Actions of the Propanediol Dicarbamates Felbamate and Meprobamate |
  3. A purinergic component in the central actions of meprobamate. |
  4. DEA Scheduled Drugs |