Prometazin

Promethazine is a first-generation antihistamine of the phenothiazine class, developed by French chemists in the mid-1940s. It functions as a depressant with strong sedative, antiemetic, and anticholinergic properties. Commonly prescribed for allergies, nausea, and motion sickness, it is also known as one of the two active ingredients in 'lean' when combined with codeine. At high or toxic doses, its anticholinergic activity can produce deliriant effects.

Also known as: Phenergan, Promethazine hcl

Classification

Chemical: Medicine
Psychoactive: Depressant
Tag: Common
Tag: Pharmaceutical
Tag: Phenothiazine antihistamine
Tag: Sedative

Effects

Pupil Dilation
Nausea Suppression
Temperature Regulation Suppression
Ataxia
Restless Legs
Respiratory Depression
Anxiety Suppression
Confusion
Cognitive Fatigue
Delirium
Dream Potentiation
Dizziness
Dehydration
Visual Acuity Suppression
Dulled Perception
Increased Music Appreciation
Internal Hallucination
Cognitive Dysphoria

Routes of Administration

Oral

Dosage

Heavy: 100 mg
Light: 12.5 - 25 mg
Common: 25 – 50 mg
Strong: 50 – 100 mg
Threshold: 5 - 12.5 mg

Duration

Onset: 0.5-1 h
Comeup: 0.33-1 h
Peak: 1-2 h
Offset: 3-5 h
After Effects: 12 h

Harm Reduction

Check interactions before mixing substances, pay attention to dose spacing and hydration, and treat all dosage guidance as approximate rather than guaranteed safe.

Sources

Substance data is aggregated from the following public harm-reduction and reference sources.

Links

This static page is intended as a readable non-JS and prerender-friendly library export.

Get the full DrugsPRO experience

Open the interactive DrugsPRO app for search, saved items, interactions, and deeper harm reduction tools.

Get the PRO test kit. The simple, quick and reliable drug checking test kit. Visit https://protestkit.eu