Sufentanil

Sufentanil is synthetic anilidopiperidine 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.

Sufentanil Citrate Injection, is an opioid agonist, available as a solution containing 50 mcg/mL eq. of Sufentanil base, adjusted to pH 3.5 to 6.0. The chemical name is N-[4-(methyoxymethyl)-1-[2-(2-thienyl)ethyl]-4-piperidinyl]-N-phenylpropanamide: 2-hydroxy-1,2,3-propanetricarboxylate (1:1). The molecular weight is 578.68. Sufentanil Citrate Injection, is a sterile, non-pyrogenic, preservative free aqueous solution for intravenous or epidural injection.^[2]

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.

Because of its extremely high potency, it is often used in surgery and post-operative pain management for patients that are heavily opioid dependent/opioid tolerant because of long term opiate use for chronic pain or illicit opiate use. Currently sufentanil is the most potent opioid painkiller available for use in humans. Although more potent narcotic pain medications do exist, all medications stronger than sufentanil are approved for veterinary use only. It is also used in surgery and postoperative pain control in patients that are taking high dose buprenorphine for chronic pain because it is the only opioid that has a potency and binding affinity strong enough to displace buprenorphine from the opioid receptors in the central nervous system and provide analgesia.Cite error: Closing </ref> missing for <ref> tag 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

Warning: Many psychoactive substances that are reasonably safe to use on their own can suddenly become dangerous and even life-threatening when combined with certain other substances. The following list provides some known dangerous interactions (although it is not guaranteed to include all of them).

Always conduct independent research (e.g. Google, DuckDuckGo, PubMed) to ensure that a combination of two or more substances is safe to consume. Some of the listed interactions have been sourced from TripSit.

• Alcohol - Both substances potentiate the ataxia and sedation caused by the other and can lead to unexpected loss of consciousness at high doses. Place affected patients in the recovery position to prevent vomit aspiration from excess. Memory blackouts are likely
• Stimulants - Stimulants increase respiration rate which allows for a higher dose of opiates than would otherwise be used. If the stimulant wears off first then the opiate may overcome the user and cause respiratory arrest.
• Benzodiazepines - Central nervous system and/or respiratory-depressant effects may be additively or synergistically present. The two substances potentiate each other strongly and unpredictably, very rapidly leading to unconsciousness. While unconscious, vomit aspiration is a risk if not placed in the recovery position blackouts/memory loss likely.
• DXM - Generally considered to be toxic. CNS depression, difficulty breathing, heart issues, and liver toxicity have been observed. Additionally if one takes DXM, their tolerance of opiates goes down slightly, thus causing additional synergistic effects.
• GHB/GBL - The two substances potentiate each other strongly and unpredictably, very rapidly leading to unconsciousness. While unconscious, vomit aspiration is a risk if not placed in the recovery position
• Ketamine - Both substances bring a risk of vomiting and unconsciousness. If the user falls unconscious while under the influence there is a severe risk of vomit aspiration if they are not placed in the recovery position.
• MAOIs - Coadministration of monoamine oxidase inhibitors (MAOIs) with certain opioids has been associated with rare reports of severe adverse reactions. There appear to be two types of interaction, an excitatory and a depressive one. Symptoms of the excitatory reaction may include agitation, headache, diaphoresis, hyperpyrexia, flushing, shivering, myoclonus, rigidity, tremor, diarrhea, hypertension, tachycardia, seizures, and coma. Death has occurred in some cases.
• MXE - MXE can potentiate the effects of opioids but also increases the risk of respiratory depression and organ toxicity.
• Nitrous - Both substances potentiate the ataxia and sedation caused by the other and can lead to unexpected loss of consciousness at high doses. While unconscious, vomit aspiration is a risk if not placed in the recovery position. Memory blackouts are common.
• PCP - PCP may reduce opioid tolerance, increasing the risk of overdose.
• Tramadol - Increased risk of seizures. Tramadol itself is known to induce seizures and it may have additive effects on seizure threshold with other opioids. Central nervous system- and/or respiratory-depressant effects may be additively or synergistically present.
• Grapefruit - While grapefruit is not psychoactive, it may affect the metabolism of certain opioids. Tramadol, oxycodone, and fentanyl are all primarily metabolized by the enzyme CYP3A4, which is potently inhibited by grapefruit juice^[4]. This may cause the drug to take longer to clear from the body. it may increase toxicity with repeated doses. Methadone may also be affected^[4]. Codeine and hydrocodone are metabolized by CYP2D6. People who are on medicines that inhibit CYP2D6, or that lack the enzyme due to a genetic mutation will not respond to codeine as it can not be metabolized into its active product: morphine.

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.

• MAOIs - Such as banisteriopsis caapi, syrian rue, phenelzine, selegiline, and moclobemide.^[5]
• Serotonin releasers - Such as MDMA, 4-FA, methamphetamine, methylone and αMT.
• SSRIs - Such as citalopram and sertraline
• SNRIs - Such as tramadol and venlafaxine
• 5-HTP

• Germany: Sufentanil is a controlled substance under Anlage III of the BtMG. It can only be prescribed on a narcotic prescription form.^[6]
• Russia: Sufentanil is a Schedule II controlled substance.^[7]
• Switzerland: Sufentanil is a controlled substance specifically named under Verzeichnis A. Medicinal use is permitted.^[8]
• United States: Sufentanil is classified as a Schedule II Controlled Substance under the Controlled Substances Act.^[9]

• Responsible use
• Opioid
• Heroin
• Morphine
• Fentanyl

• Sufentanil (Wikipedia)
• Sufentanil (Isomer Design)