Promethazine Dosage

Medically reviewed by Drugs.com. Last updated on Aug 14, 2023.

Usual Adult Dose for Allergic Reaction

Oral or Rectal: 6.25 to 12.5 mg orally or rectally before meals and at bedtime, if necessary, OR 25 mg orally or rectally once a day at bedtime

Parenteral: 25 mg IM or IV once, and may be repeated within 2 hours if necessary

Comments:

• Once treatment begins, the dose should be reduced to the smallest effective amount needed to control symptoms.
• Minor transfusion and/or amelioration of allergic reactions may be controlled with 25 mg doses.

Uses:

• Allergic conjunctivitis due to inhalant allergens and foods
• Amelioration of allergic reactions to blood or plasma
• Dermographism
• In anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
• Other uncomplicated allergic condition of the immediate type when oral therapy is impossible or contraindicated
• Perennial and seasonal allergic rhinitis
• Vasomotor rhinitis

Usual Adult Dose for Allergic Rhinitis

Oral or Rectal: 6.25 to 12.5 mg orally or rectally before meals and at bedtime, if necessary, OR 25 mg orally or rectally once a day at bedtime

Parenteral: 25 mg IM or IV once, and may be repeated within 2 hours if necessary

Comments:

• Once treatment begins, the dose should be reduced to the smallest effective amount needed to control symptoms.
• Minor transfusion and/or amelioration of allergic reactions may be controlled with 25 mg doses.

Uses:

• Allergic conjunctivitis due to inhalant allergens and foods
• Amelioration of allergic reactions to blood or plasma
• Dermographism
• In anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
• Other uncomplicated allergic condition of the immediate type when oral therapy is impossible or contraindicated
• Perennial and seasonal allergic rhinitis
• Vasomotor rhinitis

Usual Adult Dose for Anaphylaxis

Oral or Rectal: 6.25 to 12.5 mg orally or rectally before meals and at bedtime, if necessary, OR 25 mg orally or rectally once a day at bedtime

Parenteral: 25 mg IM or IV once, and may be repeated within 2 hours if necessary

Comments:

• Once treatment begins, the dose should be reduced to the smallest effective amount needed to control symptoms.
• Minor transfusion and/or amelioration of allergic reactions may be controlled with 25 mg doses.

Uses:

• Allergic conjunctivitis due to inhalant allergens and foods
• Amelioration of allergic reactions to blood or plasma
• Dermographism
• In anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
• Other uncomplicated allergic condition of the immediate type when oral therapy is impossible or contraindicated
• Perennial and seasonal allergic rhinitis
• Vasomotor rhinitis

Usual Adult Dose for Urticaria

Oral or Rectal: 6.25 to 12.5 mg orally or rectally before meals and at bedtime, if necessary, OR 25 mg orally or rectally once a day at bedtime

Parenteral: 25 mg IM or IV once, and may be repeated within 2 hours if necessary

Comments:

• Once treatment begins, the dose should be reduced to the smallest effective amount needed to control symptoms.
• Minor transfusion and/or amelioration of allergic reactions may be controlled with 25 mg doses.

Uses:

• Allergic conjunctivitis due to inhalant allergens and foods
• Amelioration of allergic reactions to blood or plasma
• Dermographism
• In anaphylaxis as an adjunct to epinephrine and other standard measures after the acute symptoms have been controlled
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
• Other uncomplicated allergic condition of the immediate type when oral therapy is impossible or contraindicated
• Perennial and seasonal allergic rhinitis
• Vasomotor rhinitis

Usual Adult Dose for Light Sedation

Oral or Rectal: 25 to 50 mg orally or rectally once

Parenteral:

• Early stages of labor: 50 mg IM or IV once
• Nighttime sedation: 25 to 50 mg IM or IV once

Comments:

• Oral and rectal formulations may be used for nighttime, presurgical, or obstetrical sedation.
• Sedative doses may be given the night before surgery.
• Preoperative doses should be given with appropriate doses of an analgesic/hypnotic and an atropine-like agent.

Uses:

• For sedation and relief of apprehension and to produce light sleep from which the patient can be easily aroused
• Preoperative, postoperative, and obstetric (during labor) sedation

Usual Adult Dose for Sedation

Oral or Rectal: 25 to 50 mg orally or rectally once

Parenteral:

• Early stages of labor: 50 mg IM or IV once
• Nighttime sedation: 25 to 50 mg IM or IV once

Comments:

• Oral and rectal formulations may be used for nighttime, presurgical, or obstetrical sedation.
• Sedative doses may be given the night before surgery.
• Preoperative doses should be given with appropriate doses of an analgesic/hypnotic and an atropine-like agent.

Uses:

• For sedation and relief of apprehension and to produce light sleep from which the patient can be easily aroused
• Preoperative, postoperative, and obstetric (during labor) sedation

Usual Adult Dose for Motion Sickness

Treatment:

• Oral and Rectal: 25 mg orally, or rectally once, then 12.5 to 25 mg every 4 to 6 hours as needed
• Parenteral: 12.5 to 25 mg IM or IV every 4 hours as needed

Prophylaxis:

• Initial day: 25 mg orally or rectally 30 to 60 minutes before traveling, then 8 to 12 hours as needed
• Succeeding days of travel: 25 mg orally or rectally upon rising, with the dose repeated before the evening meal

Comment:

• Oral formulations are preferred; however, rectal or parenteral formulations may be given if oral formulations are not tolerated.

Use:

• Active and prophylactic treatment of motion sickness

Usual Adult Dose for Nausea/Vomiting

Treatment: 12.5 to 25 mg IM, IV, orally, or rectally every 4 hours as needed

Prophylaxis:

• Oral and Rectal: 25 mg orally every 4 to 6 hours as needed

Comments:

• Parenteral or rectal formulations may be used when patients cannot tolerate oral formulations.
• Prophylactic doses may be used to prevent nausea and vomiting during surgery and the postoperative period.

Uses:

• Prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery
• Antiemetic therapy in postoperative patients

Usual Adult Dose for Opiate Adjunct

Parenteral:
Pre- or postoperative use: 25 to 50 mg IM or IV once
Established labor: 25 to 75 mg IM or IV, repeated up to 2 times in 4-hour intervals

• Maximum dose: 100 mg every 24 hours

Comments:

• The average parenteral dose given during established labor is 50 mg.
• Preoperative doses should be given with appropriate doses of an analgesic/hypnotic and an atropine-like agent.

Uses:

• Administered IV as an adjunct to anesthesia or analgesia with reduced amounts of meperidine of other narcotic analgesics in special surgical situations (e.g., repeated bronchoscopy, ophthalmic surgery, poor-risk patients)
• Therapy adjunctive to meperidine or other analgesics for control of postoperative pain

Usual Pediatric Dose for Allergic Reaction

2 years and older:
Oral or Rectal: 6.25 to 12.5 mg orally or rectally before meals and at bedtime, as necessary OR 25 mg orally or rectally once a day at bedtime

Parenteral: 12.5 mg IM or IV once, and may be repeated within 2 hours if necessary

Comments:

• Once treatment begins, the dose should be reduced to the smallest effective amount needed to control symptoms.
• Minor transfusion and/or amelioration of allergic reactions may be controlled with 12.5 mg doses.

Uses:

• Perennial and seasonal allergic rhinitis
• Vasomotor rhinitis
• Allergic conjunctivitis due to inhalant allergens and foods
• Mild, uncomplicated allergic skin manifestations of urticaria and angioedema
• Amelioration of allergic reactions to blood or plasma
• Dermographism
• Adjunctive therapy to epinephrine and other standard measures for anaphylactic reactions, after acute manifestations have been controlled

Usual Pediatric Dose for Motion Sickness

2 years and older:
Treatment:

• Parenteral: 6.25 to 12.5 mg IM or IV every 4 hours a day

Treatment and prevention:

• Oral and Rectal: 12.5 to 25 mg orally or rectally 2 times a day

Comments:

• The initial dose should be given 30 to 60 minutes before anticipated travel, and may be repeated in 8 to 12 hours as needed.
• Subsequent doses on succeeding days of travel should be given on rising and again before the evening meal.

Use:

• Active and prophylactic treatment of motion sickness

Usual Pediatric Dose for Nausea/Vomiting

2 years and older:
Treatment:
Oral or Rectal: 1.1 mg/kg orally or rectally every 4 to 6 hours as needed

• Maximum dose: 25 mg

Parenteral: 6.25 to 12.5 mg IM or IV every 4 hours as needed

Prophylaxis: Up to 25 mg orally or rectally every 4 to 6 hours as needed

Comments:

• This drug should not be used to treat nausea and vomiting of unknown etiology.
• Doses should be adjusted to the age and severity of the patient.

Uses:

• Prevention and control of nausea and vomiting associated with certain types of anesthesia and surgery
• Antiemetic therapy in postoperative patients

Usual Pediatric Dose for Light Sedation

2 years and older:
Preoperative medication: 1.1 mg/kg IM, IV, orally, or rectally once

• Maximum dose: Up 25 mg

Sedation and/or adjunctive use with analgesics: 12.5 to 25 mg IM, IV, orally, or rectally once

Comments:

• Sedative doses may be given the night before surgery.
• Preoperative doses should be given with appropriate doses of an analgesic/hypnotic and an atropine-like agent.

Uses:

• Preoperative, postoperative, or obstetric sedation
• Relief of apprehension and production of light sleep from which the patient can be easily aroused

Usual Pediatric Dose for Sedation

2 years and older:
Preoperative medication: 1.1 mg/kg IM, IV, orally, or rectally once

• Maximum dose: Up 25 mg

Sedation and/or adjunctive use with analgesics: 12.5 to 25 mg IM, IV, orally, or rectally once

Comments:

• Sedative doses may be given the night before surgery.
• Preoperative doses should be given with appropriate doses of an analgesic/hypnotic and an atropine-like agent.

Uses:

• Preoperative, postoperative, or obstetric sedation
• Relief of apprehension and production of light sleep from which the patient can be easily aroused

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Use with caution.

Dose Adjustments

65 years and older: Elderly patients should be given lower initial doses and should be closely monitored for adverse events.

Precautions

US BOXED WARNINGS:

• RESPIRATORY DEPRESSION (PEDIATRIC PATIENTS): This drug should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression. Post-marketing cases of respiratory depression, including fatalities, have been reported with use of this drug in pediatric patients less than 2 years of age. A wide range of weight-based doses have resulted in respiratory depression in these patients. Caution should be exercised when administering parenteral formulations in pediatric patients 2 years of age and older; it is recommended that the lowest effective dose of oral formulations be used in and concomitant administration of other drugs with respiratory depressant effects be avoided in this patient population.
• SEVERE TISSUE INJURY, INCLUDING GANGRENE: Parenteral formulations can cause severe chemical irritation and damage to tissues regardless of the route of administration. Irritation and damage can result from perivascular extravasation, unintentional intra-arterial injection, and intraneuronal/perineuronal infiltration. Adverse reactions include burning, pain, thrombophlebitis, tissue necrosis, and gangrene. In some cases, surgical intervention, including fasciotomy, skin graft, and/or amputation have been required. Deep IM injection is the preferred route of administration. Subcutaneous administration is contraindicated.

Safety and efficacy have not been established in patients younger than 2 years.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• The injection solution should be inspected for particulate matter and discoloration before administration. Subcutaneous administration is contraindicated.
• IV: Treatment should be injected into a large vein, avoiding sites in the hand/wrist if possible. This drug should be administered at a rate no greater than 25 mg/min.
• Oral solution: The oral solution should be measured with an accurate measuring device to decrease the risk of overdosage. Household teaspoons may not be an accurate measuring device.

Storage requirements:

• Parenteral formulations: Store ampoules in the carton until ready to use.
• Suppositories: Keep refrigerated.
• Tablets: Protect from light.

Reconstitution/preparation techniques:

• IV formulations should be diluted to a concentration of 25 mg/mL or less.

General:

• Parenteral formulations of this drug may cause severe chemical irritation and tissue damage regardless of the route.

Monitoring:

• Excessive sedation
• Respiratory rate, especially in pediatric patients
• Localized injection site reactions

Patient advice:

• Patients should be told to report any involuntary muscle movements.
• Patients receiving parenteral formulations should report persistent/worsening pain or burning at the injection site.
• Patients should be advised to avoid prolonged sun exposure during treatment.
• Inform patients that this drug may cause drowsiness, and they should avoid driving or operating machinery until the full effects of the drug are seen.

Frequently asked questions

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See also:

Further information

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