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Promethazine is a first-generation antihistamine of the phenothiazine family. The drug has anti-motion sickness, antiemetic, and anticholinergic effects, as well as a strong sedative effect and in some countries is prescribed for insomnia when benzodiazepines are contraindicated. It is available over-the-counter in the United Kingdom, Australia, Switzerland, and many other countries, but by prescription in the United States. Brand names for promethazine include, in alphabetical order: Atosil, Avomine, Fargan, Farganesse, Lergigan, Phenergan, Promethegan, Prothiazine, Receptozine, Romergan and Sominex in the UK.

Some common side effects include:

  • Tardive dyskinesia
  • Confusion in the elderly
  • Drowsiness, dizziness, fatigue, more rarely vertigo
  • Dry mouth
  • Respiratory depression in patients under age of 2 and in those with severely compromised pulmonal function
  • Constipation
  • Chest discomfort/pressure (typically in cases when patient is already taking medication for high blood pressure)
  • Euphoria (very rare, except with high IV doses and/or coadministration with opioids/CNS depressants)
  • Akathisia
  • Paresthesia
  • Short temper/irritability

Extremely rare side effects include:

  • Seizures
  • Neuroleptic malignant syndrome (NMS)

Because of potential for more severe side effects, this drug is on the list to avoid in the elderly. (See NCQA’s HEDIS Measure: Use of High Risk Medications in the Elderly.)

Lethal dose[edit]


  1. PHENERGAN (promethazine)
    • Minimal Dose : 5 g (EXA)[2]
    • Suggested Dose : 6 g (EXE)[3],
  2. 240 comp. at 25 mg.
  3. Without prescription.

Mechanism of action[edit]

You'll fall asleep and die silently. The probability of death depends on how fast you can be treated.


In many countries worldwide, you can legally buy Phenergan (promethazine) without a prescription.

The Cocktail[edit]


  • Option #1:
Drug Amount
Antiemetic drugs must be taken beforehand  
Template:Interwiki (Base) 6 grams
  • Option #2:

The "Lytic Cocktail" (Phénergan, Largactil and Dolosal) used in France for euthanasia.[4]


  1. "Suicide mode d'emploi" (p. 182)
  2. EXA : A guide to self-deliverance. Exit England, june 1981.
  3. How to die with dignity, by George B. Mair. Exit Écosse, s;d; (sept. 1980)
  4. Faut-il légaliser l’euthanasie ?