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Propylhexedrine
Propylhexedrine is a stimulant1 classified as a cyclohexylalkylamine2, used medically in nasal inhalers to temporarily relieve congestion caused by colds and allergies.3 It was first used medically in 1949.2 It is structurally similar to methamphetamine, with a cyclohexane ring replacing the phenyl ring.4 Its free base is a volatile liquid that evaporates gradually, allowing administration by inhalation. Recreational use can be habit-forming.5
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Subjective Effects
Pharmacology
Pharmacodynamics
Propylhexedrine promotes norepinephrine, dopamine, and serotonin release by reversing their transporters, increasing the availability of these neurotransmitters at synapses.6 It also antagonizes VMAT2, causing increased neurotransmitter release.6 Its TAAR1 agonism promotes dopamine transporter phosphorylation through protein kinase A and C signaling, contributing to dopamine reuptake inhibition and transporter reversal. Propylhexedrine also acts as an alpha-adrenergic agonist7, producing blood vessel constriction, and modulates the alpha-2C adrenergic receptor.
Pharmacokinetics
Propylhexedrine is metabolized through N-demethylation, C-oxidation, N-oxidation, dehydrogenation, and hydrolysis. Cytochrome P450 enzymes contribute to its metabolism, with computational predictions identifying CYP2D6 as a substrate pathway. Its reported elimination half-life is 2.5-6.5 hours; higher urinary pH slows elimination, while lower urinary pH and greater activity of certain cytochrome P450 enzymes speed it up. Computational predictions also suggest intestinal absorption, blood-brain barrier penetration, and permeability across Caco-2 intestinal cell models. These predictions classify it as neither a P-glycoprotein substrate nor inhibitor, neither a CYP2C9 nor CYP3A4 substrate, and a non-inhibitor of the renal organic cation transporter and CYP1A2, CYP2C9, CYP2D6, CYP2C19, and CYP3A4.
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
All dopaminergic stimulants
Harm Potential
Addiction & Dependence
Psychological
HighChronic propylhexedrine use is described as highly addictive, although its overall abuse potential is assessed as moderate. Psychological dependence can develop, with cravings after abrupt cessation or a substantial reduction in use.
Physical
Chronic propylhexedrine use can produce physical dependence and tolerance. Withdrawal effects may occur when dependent users abruptly stop or substantially reduce use.
Toxicity
Recreational misuse of propylhexedrine products has caused fatalities,5 and injection increases the risks associated with recreational use. Overdoses most often involve recreational administration inconsistent with product labeling.
Propylhexedrine increases heart rate and blood pressure and constricts blood vessels; palpitations are commonly reported at common to heavy doses. Recreational misuse can cause serious cardiovascular complications, including rapid or abnormal heart rhythms, hypertension, and chest pain, with possible hospitalization, disability, or death.5
Propylhexedrine administered by inhaler may cause temporary nasal burning or stinging, and frequent or prolonged use may cause nasal congestion to worsen or recur.8
Psychosis Risk
Propylhexedrine abuse can cause stimulant-induced psychosis with paranoia, hallucinations, and delusions; psychosis is also reported in acute overdose. Serious psychiatric complications associated with misuse can require hospitalization or cause disability.5
History & Culture
Development and medical introduction
Propylhexedrine was developed during a search for safer nasal decongestants. In 1948, Dr. Glenn E. Ullyot patented its use as a decongestant for Smith, Kline & French. Market trials in California began on July 15, 1949, before its national introduction in the United States. Smith, Kline & French…
Legality
International
Controlled internationally under the UN Convention on Psychotropic Substances 1971.
By Country
References
Source Pages
Citations
Further Reading
Article Status
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