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

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


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As such, it may contain incorrect grammar, spelling, or punctuation.

Summary sheet: Sufentanil
Chemical Nomenclature
Common names Sufentanil, sufentanyl, Sufenta, Chronogesic,
Systematic name N-[4-(Methoxymethyl)-1-(2-thiofuran-2-ylethyl)-4-piperidyl]-N-phenylpropanamide
Class Membership
Psychoactive class Opioid
Chemical class Piperidine
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 0.1 - 1 μg
Light 1 - 5 μg
Common 5 - 10 μg
Strong 10 - 25 μg
Heavy 25 μg +
Onset 1 - 2 minutes
Peak 5 - 10 minutes
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.

Sufentanil, also known as sufentanyl and by the brand name Sufenta, is an extremely potent synthetic piperidine opioid analgesic. Sufentanil has a rapid onset and short mechanism and is used medically as an analgesic in surgical procedures or for the management of post-operative pain. Sufentanil is roughly 500 to 1,000 times more potent than pharmaceutical grade morphine and is approximately 10 times more potent than pharmaceutical grade fentanyl. The subjective effects of sufentanil are similar to those of heroin, with the exception that many users report a significantly less euphoric "high" associated with the drug and stronger respiratory depression, sedation and pain relief. Sufentanil is the most potent opioid analgesic currently used in human medicine.


Sufentanil is synthetic piperidine that is similar in structure to both fentanyl and acetylfentanyl. One of the key differences is that one of the phenyl groups in sufentanil has been replaced with a thiophene or thiofuran group. Thiophene groups can typically replace phenyl groups without a significant drop in potency. The empirical formula of sufentanil is C22H30N2O2S and has a molar mass of 386.552 grams per mole.


The recreational effects of sufentanil occur because opioids structurally mimic endogenous endorphins which are naturally found within the body and also work upon the μ-opioid receptor set. The way in which opioids structurally mimic these natural endorphins results in their euphoria, pain relief and anxiolytic effects. This is because endorphins are responsible for reducing pain, causing sleepiness, and feelings of pleasure. They can be released in response to pain, strenuous exercise, orgasm, or general excitement. Like endorphins, sufentanil is an extremely potent μ-opioid agonist.

Sufentanil has an extremely short biological half life of only 162 minutes.

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

Cognitive effects

Toxicity and harm potential

Recreational use of sufentanil by individuals without opioid tolerance is extremely dangerous due to its potency. It is potentially fatal at heavy dosages and even those with opiate tolerances are at high risk for overdoses. Once the sufentanil is in the user's system, it is extremely difficult to stop its course because of the nature of absorption. Because of the extremely high strength of pure sufentanil powder, it is very difficult to dilute appropriately, and often the resulting mixture may be far too strong and, therefore, very dangerous. It is also potentially lethal when mixed with depressants like alcohol or benzodiazepines.

Like most opioids, unadulterated sufentanil at appropriate dosages does not cause many long-term complications other than dependence and constipation. Outside of the extremely powerful addiction and physical dependence, the harmful or toxic aspects of opioid usage are exclusively associated with not taking the necessary precautions in regards to its administration, overdosing and using impure products.

It is important to consider that particular care must be taken with sufentanil due to its extreme potency and ability to be absorbed through the skin. This means that simply unintentionally spilling a very small amount of sufentanil on one's skin could result in a fatal overdose.

Heavy dosages of sufentanil can result in respiratory depression, leading onto fatal or dangerous levels of anoxia (oxygen deprivation). This occurs because the breathing reflex is suppressed by agonism of µ-opioid receptors proportional to the dosage consumed.

Sufentanil can also cause nausea and vomiting; a significant number of deaths attributed to opioid overdose are caused by aspiration of vomit by an unconscious victim. This is when an unconscious or semi-conscious user who is lying on their back vomits into their mouth and unknowingly suffocates. It can be prevented by ensuring that one is lying on their side with their head tilted downwards so that the airways cannot be blocked in the event of vomiting while unconscious (also known as the recovery position). In case of overdose, it is advised to administer a dose of naloxone intravenously or intramuscularly to reverse the effects of opioid agonism. It has been noted that naloxone is not very effective for the management of opioid overdoses in cases where extremely potent opioids like sufentanil have been used. In the case of sufentanil, naltrexone should be used in case of an overdose.

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

Tolerance and addiction potential

As with other opioids, the chronic use of sufentanil can be considered extremely addictive with a high potential for abuse and is capable of causing psychological dependence among certain users. When addiction has developed, cravings and withdrawal symptoms may occur if a person suddenly stops their usage.

Tolerance to many of the effects of sufentanil develops with prolonged and repeated use. The rate at which this occurs develops at different rates for different effects, with tolerance to the constipation-inducing effects developing particularly slowly for instance. This results in users having to administer increasingly large doses to achieve the same effects. It is unknown how long it takes for sufentanil tolerance to decrease to baseline (no distinguishable tolerance). Sufentanil presents cross-tolerance with all other opioids, meaning that after the consumption of sufentanil all opioids will have a reduced effect.

The risk of fatal opioid overdoses rise sharply after a period of cessation and relapse, largely because of reduced tolerance.[2] To account for this lack of tolerance, it is safer to only dose a fraction of one's usual dosage if relapsing. It has also been found that the environment one is in can play a role in opioid tolerance. In one scientific study, rats with the same history of heroin administration were significantly more likely to die after receiving their dose in an environment not associated with the drug in contrast to a familiar environment.[3]

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 safe 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, 2m2b, alcohol, barbiturates, benzodiazepines, GHB/GBL, methaqualone) - 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 attempt to fall asleep in the recovery position or have a friend move them into it.
  • Dissociatives - This combination can result in 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 dangerous to combine fentanyl, a depressant, with stimulants due to the risk of excessive intoxication. Stimulants decrease the sedative effect of fentanyl, which is the main factor most people consider when determining their level of intoxication. Once the stimulant wears off, the effects of fentanyl will be significantly increased, leading to intensified disinhibition as well as other effects. If combined, one should strictly limit themselves to taking a certain amount of fentanyl.

Serotonin syndrome risk

Combinations with the following substances can cause dangerously high serotonin levels. Serotonin syndrome requires immediate medical attention and can be fatal if left untreated.

Legal issues


This legality section is a stub.

As such, it may contain incomplete or wrong information. You can help by expanding it.

  • United States - Sufentanil is classified as a Schedule II Controlled Substance under the Controlled Substances Act.[5]

See also

External links


  1. Risks of Combining Depressants (Tripsit) |
  2. Why Heroin Relapse Often Ends In Death - Lauren F Friedman (Business Insider) |
  3. Siegel, S., Hinson, R., Krank, M., & McCully, J. (1982). Heroin “overdose” death: contribution of drug-associated environmental cues. Science, 216(4544), 436–437.
  4. Gillman, P. K. (2005). Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity. British Journal of Anaesthesia, 95(4), 434-441.
  5. Controlled Drugs |