|Summary sheet: Propylhexedrine|
|Common names||Propylhexedrine, Benzedrex|
|Substitutive name||Benzedrex, Obesin|
|Routes of Administration|
Propylhexedrine (commonly known as Benzedrex and Obesin) is a stimulant substance of the cycloalkylamine class. Propylhexedrine is widely used medicinally as a nasal decongestant (for relief of congestion due to colds, allergies and allergic rhinitis) and sometimes used recreationally as an over-the-counter "legal high". It is a structural analog of methamphetamine.
In the United States, propylhexedrine is most commonly found in over-the-counter Benzedrex nasal inhalers. Benzedrex was first manufactured by Smith, Kline and French after the Benzedrine inhaler, which contained racemic amphetamine, became unavailable following the placement of amphetamines on the US Schedule II status (highest abuse potential, yet with accepted medicinal uses). Propylhexedrine has also seen use in Europe as an appetite suppressant under the trade name Obesin.
- 1 Chemistry
- 2 Pharmacology
- 3 Subjective effects
- 4 Toxicity and harm potential
- 5 Legal status
- 6 See also
- 7 External links
- 8 References
Propylhexedrine is chemically classified as a cycloalkylamine. It is structurally similar to phenethylamine and its derivates. It is particularly similar in structure to methamphetamine, with the only structural difference being the substitution of an cyclohexane ring for methamphetamine's phenyl ring. This makes propylhexedrine a structural analog of methamphetamine.
Moreover, propylhexedrine is a chiral compound (the α-carbon is chiral), and the product contained in pharmaceutical products is racemic (RS)-propylhexedrine free base. (S)-Propylhexedrine, also known as levopropylhexedrine, is believed to be the more biologically active isomer of the two, although amphetamines with a "levo" suffix are less active than their counterparts. (S)-Propylhexedrine can be synthesized from methamphetamine.
Propylhexedrine freebase is nonpolar, volatile, oily liquid at room temperature, but it readily forms a polar salt with hydrochloric acid, citric acid, and acetic acid, which is a crystalline white substance.
Propylhexedrine affects the central nervous system (CNS) by acting as a releasing agent for the monoamine neurotransmitters dopamine, norepinephrine, and serotonin (SNDRA), binding to and reversing their transporters, pumping these neurotransmitters from the cytosol to the synaptic cleft, where these neurotransmitters can bind to their respective receptors. Additionally, propylhexedrine inhibits VMAT2, leading to a further increase in the aforementioned monoamines, being that VMAT2 transports all 3 from the synaptic cleft to the cytosol.
Propylhexedrine, like phenethylamine, amphetamine, methamphetamine, and MDMA, agonizes TAAR1. TAAR1 agonism, through protein kinase A & C (PKA and PKC) signaling, causes dopamine transporter (DAT) phosphorylation. Both PKA and PKC result in non-competitive dopamine reuptake inhibition, although PKC alone results in dopamine release/DAT reversal.
The pharmacological actions of propylhexedrine are similar to those of phenethylamines, such as amphetamines, albeit in a generally less centrally active and recreationally desirable fashion.
Since propylhexedrine has a cyclohexane ring in the place of methamphetamine's phenyl ring, it lacks the level of Brain-Blood Barrier permeability that the phenyl ring provides amphetamines, and therefore has a greater proportion of effects on the peripheral nervous system relative to the central nervous system.
Propylhexedrine has a half-life of 2.5 - 6.5 hours, which is variable based on urinary pH and the level of activity of certain Cytochrome P450 enzymes. Higher urinary pH elongates duration, while low urinary pH shortens duration. Higher activity of certain Cytochrome P450 enzymes also shortens duration.
Propylhexedrine is metabolized by certain Cytochrome P450 enzymes into norpropylhexedrine, cyclohexylacetoxime, cis-4-hydroxypropylhexedrine and trans-4-hydroxypropylhexedrine.
|This subjective effects section is a stub.|
As such, it is still in progress and may contain incomplete or wrong information.
You can help by expanding or correcting it.
Disclaimer: The effects listed below are cited from the Subjective Effect Index (SEI), which relies on assorted anecdotal reports and the personal experiences of PsychonautWiki contributors. As a result, they should be taken with a healthy amount of skepticism. It is worth noting that these effects will not necessarily occur in a consistent or reliable manner, although higher doses (common+) are more likely to induce the full spectrum of reported effects. Likewise, adverse effects become much more likely on higher doses and may include serious injury or death.
- Stimulation - In terms of its effects on the physical energy levels of the user, propylhexedrine is usually considered to be extremely energetic and stimulating in a fashion that is extremely similar to that of amphetamine or methamphetamine, and stronger than that of modafinil, caffeine, and methylphenidate. It is similar to the stimulation experienced on racemic or the levorotorary form of amphetamine or the racemic methamphetamine, encouraging physical activities such as dancing, socializing, running, or cleaning. The particular style of stimulation which propylhexedrine presents can be described as forced or pressing and is noticeably more adrenergic and tense on the body. This means that at higher dosages, it becomes difficult or impossible to keep still as jaw clenching, involuntarily bodily shakes and vibrations become present, resulting in extreme shaking of the entire body, unsteadiness of the hands, and a general lack of motor control.
- Abnormal heartbeat - Heart palpitations are commonly reported on common to heavy doses of this substance due to its significant peripheral nervous system activity.
- Increased blood pressure - Propylhexedrine has been noted by users to raise blood pressure significantly more than other stimulants. It has been speculated that this is due to its higher affinity for noradrenaline relative to stimulants such as amphetamine.
- Increased heart rate - Due to its pronounced peripheral nervous system activity, propylhexedrine tends to increase heart rate much more drastically than comparable dosages of other stimulants.
- Pupil dilation
- Appetite suppression
- Frequent urination
- Increased bodily temperature
- Increased perspiration
- Nausea - This effect is prominent on the onset and come up period when ingested via the cotton found inside Benzedrex inhalers, particularly when it is taken on an empty stomach.
- Stamina enhancement
- Teeth grinding
- Temporary erectile dysfunction
- Vasoconstriction - Propylhexedrine has been noted by users as being particularly vasoconstrictive in comparison to other stimulants. It has been speculated that this is due to its higher affinity for noradrenaline relative to stimulants such as amphetamine.
As with amphetamine or methamphetamine, the visual effects of propylhexedrine are usually less consistent and are only mildly noticeable at higher dosages. They are somewhat comparable to the visual effects produced by deliriants and are generally more frequent in darker areas.
- Double vision - An uncommon effect that only occurs at very high, potentially dangerous or toxic dosages.
The cognitive effects of propylhexedrine can be broken down into several components which progressively intensify proportional to dosage. The general head space of propylhexedrine is described by many as one of moderate to extreme mental stimulation, increased focus, and powerful euphoria. It contains a large number of typical stimulant cognitive effects. Although negative side effects are usually mild at low to moderate dosages, they become increasingly likely to manifest themselves with higher amounts or extended usage. This particularly holds true during the offset of the experience.
The most prominent of these cognitive effects generally include:
- Euphoria - The euphoria capable of being produced by propylhexedrine is reported to be similiar to that of methamphetamine at high doses.
- Analysis enhancement
- Compulsive redosing
- Ego inflation
- Focus enhancement - This component is most effective at low to moderate dosages as anything higher will usually impair concentration.
- Increased libido
- Increased music appreciation
- Memory enhancement
- Motivation enhancement
- Thought acceleration
- Thought organization
The effects which occur during the offset of a stimulant experience generally feel negative and uncomfortable in comparison to the effects which occurred during its peak. This is often referred to as a "comedown" and occurs because of neurotransmitter depletion. Its effects commonly include:
- Appetite suppression
- Cognitive fatigue
- Depression - Due to depletion of the essential neurotransmitters serotonin,dopamine, and norepinephine, propylhexedrine can cause moderate to strong feelings of depression after large doses.
- Motivation suppression
- Thought deceleration
- Wakefulness - According to anecdotal reports, residual feelings of wakefulness can persist for up to 12 hours after the initial high wears off.
Anecdotal reports which describe the effects of this compound within our experience index include:
Additional experience reports can be found here:
Toxicity and harm potential
The toxicity of recreational propylhexedrine use has not been studied as extensively as that of amphetamine or methamphetamine but it is reasonable to assume that most if not all of the same risks apply.
It is strongly recommended that one use harm reduction practices when using this substance.
Tolerance and addiction potential
As with other stimulants, the chronic use of propylhexedrine can be considered highly addictive, and is capable of causing psychological and physiological dependence among certain users. When addiction has developed, cravings and withdrawal effects may occur if a person suddenly stops or drastically decreases their usage.
Tolerance to the effects of this compound likely occurs in the same general fashion as with amphetamine rapidly develops with prolonged and repeated use. This results in users having to administer increasingly large doses to achieve the same effects. After that, it takes about 3 - 7 days for the tolerance to be reduced to half and 1 - 2 weeks to be back at baseline (in the absence of further consumption). Propylhexedrine presents cross-tolerance with all dopaminergic stimulants, meaning that after the consumption of propylhexedrine all stimulants will have a reduced effect.
Like with amphetamine and methamphetamine the evidence on effective treatments for dependence and abuse is limited. In light of this, fluoxetine and imipramine appear to have some limited benefits in treating abuse and addiction
In highly dependent amphetamine and methamphetamine abusers, "when chronic heavy users abruptly discontinue methamphetamine use, many report a time-limited withdrawal syndrome that occurs within 24 hours of their last dose". Withdrawal symptoms in chronic, high-dose users are frequent, occurring in up to 87.6% of cases, and persist for three to four weeks with a marked "crash" phase occurring during the first week. Methamphetamine withdrawal symptoms can include anxiety, drug craving, dysphoric mood, fatigue, increased appetite, increased movement or decreased movement, lack of motivation, sleeplessness or sleepiness, and vivid or lucid dreams. Withdrawal symptoms are associated with the degree of dependence (i.e., the extent of abuse). The mental depression associated with methamphetamine withdrawal lasts longer and is more severe than that of cocaine withdrawal.. It is likely that propylhexedrine abuse is subject to these same outcomes.
Like with the abuse of methamphetamine, propylhexedrine abuse can result in a stimulant-induced psychotic state that may present with a variety of symptoms (e.g., paranoia, hallucinations, delusions), though likely to a lesser degree. A review on treatment for amphetamine, dextroamphetamine, and methamphetamine abuse-induced psychosis states that about 5–15% of users fail to recover completely. The same review asserts that, based upon at least one trial, antipsychotic medications effectively resolve the symptoms of acute amphetamine psychosis.
Although many psychoactive substances are reasonably safe to use on their own, they can quickly become dangerous or even life-threatening when combined with other substances. The list below includes some known dangerous combinations (although it cannot be guaranteed to include all of them). Independent research (e.g. Google, DuckDuckGo) should always be conducted to ensure that a combination of two or more substances is safe to consume. Some interactions listed have been sourced from TripSit.
- Tricyclic antidepressants - Propylhexedrine may increase the effects of tricyclic antidepressants to dangerous levels.
- 25x-NBOMe & 25x-NBOH - Members of the 25x family are highly stimulating and physically straining. Combinations with stimulants should be avoided due to the risk of excessive stimulation. This can result in panic attacks, thought loops, seizures, increased blood pressure, vasoconstriction, and heart failure in extreme cases.
- Alcohol - Alcohol can be dangerous to combine with stimulants due to the risk of accidental over-intoxication. Stimulants mask the sedative effects of alcohol, which is the main factor people use to assess their degree of intoxication. Once the stimulant wears off, the depressant effects of alcohol are left unopposed, which can result in blackouts and respiratory depression. If combined, one should strictly limit themselves to only drinking a certain amount of alcohol per hour.
- DXM - Combinations with DXM should be handled with extreme care due to DXM's effects on serotonin and norepinephrine reuptake. This can lead to panic attacks, hypertensive crisis, or serotonin syndrome with stimulants that increase levels of serotonin (MDMA, methylone, mephedrone, etc.). Monitor blood pressure carefully and avoid strenuous physical activity.
- MDMA - The neurotoxic effects of MDMA may be increased when combined with other stimulants. There is also a risk of excessive heart strain.
- MXE - Combinations with MXE may dangerously elevate blood pressure and increase the risk of psychosis.
- Stimulants - Propylhexedrine can be potentially dangerous in combination with other stimulants as they can increase one's heart rate and blood pressure to dangerous levels.
- Cocaine - This combination may increase strain on the heart.
- Tramadol - Tramadol lowers the seizure threshold. Combinations with stimulants may further increase this risk.
- MDMA - Like with amphetamines, the neurotoxic effects of MDMA may be increased when combined with propylhexedrine.
- MAOIs - This combination may increase the amount of neurotransmitters such as dopamine to dangerous or even fatal levels. Examples include syrian rue, banisteriopsis caapi, 2C-T-2, 2C-T-7, αMT, and some antidepressants.
- Cocaine - This combination may increase strain on the heart to dangerous levels.
This legality section is a stub.
As such, it may contain incomplete or wrong information. You can help by expanding it.
- Canada: Propylhexedrine is not controlled under the schedules to the Controlled Drugs And Substances Act.
- Germany: Propylhexedrine is a prescription only medicine, according to Anlage 1 AMVV (Medicine Prescribing Regulation, Schedule 1).
- United States: Propylhexedrine is a legal OTC drug. It is designed not to be recreationally used unless the user decides to bypass the manufacturer's intended design with which it was granted approval to market as a nasal decongestant. The simple consumption of this substance is not technically considered illegal.
- K. K. Midha, A. H. Beckett & A. Saunders (1974) Identification of the Major Metabolites of Propylhexedrine in vivo (in man) and in vitro (in guinea pig and rabbit), Xenobiotica, 4:10, 627-635, DOI: 10.1080/00498257409169765
- Efficacy of psychostimulant drugs for amphetamine abuse or dependence (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/23996457
- Amphetamines, By Patrick G. O’Connor, MD, MPH, Yale University School of Medicine | http://www.merckmanuals.com/home/special_subjects/drug_use_and_abuse/amphetamines.html
- Treatment for amphetamine dependence and abuse (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/11687171
- Treatment for amphetamine withdrawal (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/19370579
- Methamphetamine abuse (PubMed.gov / NCBI) | http://www.ncbi.nlm.nih.gov/pubmed/17990840
- Shoptaw, S. J., Kao, U., & Ling, W. (2009). Treatment for amphetamine psychosis. The Cochrane Library.
- Hofmann FG (1983). A Handbook on Drug and Alcohol Abuse: The Biomedical Aspects (2nd ed.). New York: Oxford University Press. p. 329. ISBN 9780195030570.
- Adderall Prescription info | http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021303s026lbl.pdf
- Talaie, H., Panahandeh, R., Fayaznouri, M. R., Asadi, Z., & Abdollahi, M. (2009). Dose-independent occurrence of seizure with tramadol. Journal of Medical Toxicology, 5(2), 63-67. https://doi.org/10.1007/BF03161089
- Gillman, P. K. (2005). Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity. British Journal of Anaesthesia, 95(4), 434-441. https://doi.org/10.1093/bja/aei210
- "Anlage 1 AMVV" (in German). Bundesministerium der Justiz und für Verbraucherschutz. Retrieved December 28, 2019.