What is/are Promethazine?
Promethazine is a neuroleptic medication and first-generation antihistamine of the phenothiazine family. The drug has strong sedative and weak antipsychotic effects. It also reduces motion sickness and has antiemetic and anticholinergic properties. In some countries it is prescribed for insomnia when benzodiazepines are contraindicated. It is available in many countries under the brand names Phenergan, Promethegan, Romergan, Fargan, Farganesse, Prothiazine, Avomine, Atosil, Receptozine, Lergigan, and (in the UK) Sominex.
- As a sedative
- For preoperative sedation and to counteract postnarcotic nausea
- To reduce nervousness, restlessness and agitation caused by psychiatric conditions (used for this purpose mainly in Europe)
- As antiallergic medication to combat hay fever (allergic rhinitis), etc., or to treat allergic reactions, alone or in combination with oral decongestants such as pseudoephedrine
- As an adjunct treatment for anaphylactoid conditions (IM/IV route preferred)
- Together with codeine or dextromethorphan against cough
- As a motion sickness or seasickness remedy when used with ephedrine or pseudoephedrine
- To combat moderate to severe morning sickness and hyperemesis gravidarum: In the UK, promethazine is drug of first choice, being preferred as an older drug with which there is a greater experience of use in pregnancy (second in line being metoclopramide or prochlorperazine)
- Previously, it was used as an antipsychotic, although it is generally not administered for this purpose now; promethazine has only approximately 1/10 of the antipsychotic strength of chlorpromazine.
- Also, it is used to potentiate any opiates, commonly combined with pethidine (meperidine, or Demerol) in a brand called Mepergan, a meperidine/promethazine combination. It is frequently used in conjunction with codeine, in a syrup form. The combination leads to more powerful euphoric effects than with codeine alone.
- Treatment for migraines
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 two and in those with severely compromised pulmonary function
- 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 
- Short temper/irritability
Extremely rare side effects include:
- Neuroleptic malignant syndrome
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). In many countries (including the US and UK), promethazine is contraindicated in children less than two years of age, and strongly cautioned against in children between two and six, due to problems with respiratory depression and sleep apnoea.
This article uses material from the Wikipedia article Promethazine, which is released under the Creative Commons Attribution-Share-Alike License 3.0.