WHO Model Prescribing Information: Drugs Used in Anaesthesia
(1989; 60 pages) [French] Ver el documento en el formato PDF
Índice de contenido
Ver el documentoPreface
Ver el documentoIntroduction
Cerrar esta carpetaPremedication
Ver el documentoAtropine
Ver el documentoChloral hydrate
Ver el documentoDiazepam
Ver el documentoPromethazine
Abrir esta carpeta y ver su contenidoGeneral anaesthetics and oxygen
Abrir esta carpeta y ver su contenidoLocal anaesthetics
Abrir esta carpeta y ver su contenidoNon-opioid analgesics
Abrir esta carpeta y ver su contenidoOpioid analgesics and antagonists
Abrir esta carpeta y ver su contenidoMuscle relaxants and cholinesterase inhibitors
Abrir esta carpeta y ver su contenidoBlood substitutes
Abrir esta carpeta y ver su contenidoSolutions for correcting water and electrolyte imbalance
Abrir esta carpeta y ver su contenidoAntacid for use in obstetric practice
Ver el documentoAnaesthesia at the District Hospital
Ver el documentoSelected WHO publications of related interest
Ver el documentoBack cover


Group: sedative
Tablet: 10 mg, 25 mg (hydrochloride)
Elixir or syrup: 5 mg (hydrochloride) in 5 ml
Injection: 25 mg (hydrochloride)/ml in 2-ml ampoule

General information

Promethazine is an antihistaminic and sedative phenothiazine derivative with antiemetic and anticholinergic properties. It acts for about 12 hours following oral administration and is excreted in the urine, largely as metabolites, within 24 hours.

Clinical information


Premedication prior to surgical anaesthesia and sedation in obstetrics.

Dosage and administration

Adults: 25 mg i.m. 1 hour prior to induction.
Children over 1 year: 0.5-1 mg/kg orally as syrup or tablet, 1 hour prior to induction.


• Known hypersensitivity to promethazine or to other phenothiazine derivatives (since cross-sensitivity may occur).

• Age under 1 year.

• Impaired consciousness due to cerebral depressants or of other origin.


Ambulatory patients should be warned that promethazine may impair their ability to drive or operate machinery for up to 24 hours.

Use in pregnancy and lactation

Promethazine should be used in pregnancy only when the need outweighs any potential risk to the fetus. Sufficient promethazine is excreted in maternal milk to sedate breast-fed infants.

Adverse effects

Adverse effects, which occur less frequently than with other phenothiazines, are usually referable to gastrointestinal irritation, allergic phenomena and dose-related central and anticholinergic effects.

Gastrointestinal effects include anorexia, nausea, vomiting, epigastric distress, constipation and diarrhoea. They may be attenuated by taking the drug with meals.

Allergic phenomena include urticaria and dermatitis. Agranulocytosis is very rare. Cholestatic jaundice, which is usually reversible on withdrawal of treatment, has been reported.

Central effects include sedation, dizziness, fatigue, insomnia, nightmares, hallucinations, nervousness, tremor, tinnitus, incoordination, diplopia and blurred vision.

Anticholinergic effects include dryness of the mouth, urinary frequency and palpitations.

Drug interactions

The sedative effect of alcohol and other cerebral depressants is augmented.

Concurrent use of epinephrine may result in hypotension and tachycardia due to partial adrenergic blockade.


Serious poisoning is characterized by muscular twitching, convulsions, restlessness, irritability, confusion, hallucinations and coma. Gastric lavage is of value if undertaken within a few hours of ingestion. Emetics may be ineffective. Oxygen and assisted ventilation are required in the event of respiratory depression. Seizures may be controlled with diazepam.


Promethazine should be stored in well-closed containers protected from light and should not be allowed to freeze. The syrup is less stable than the other dosage forms.

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