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Meperidine / Promethazine Dosage

Applies to the following strengths: 25 mg-25 mg/mL; 50 mg-25 mg

Usual Adult Dose for Pain

One capsule (meperidine 50 mg-promethazine 25 mg) orally every 4 to 6 hours as needed for pain.


  • The oral combination product has not been found to be safe and effective by the US FDA; its labeling has not been approved by the FDA.
  • The parenteral combination product is approved by the US FDA; however, it is not currently marketed.

Uses: This drug is possibly effective as an analgesic for moderate to moderately-severe pain. Because of the risks of addiction, abuse, and misuse, this drug should only be used in patients for whom alternative treatment options have not been tolerated or are not expected to be tolerated.

Renal Dose Adjustments


  • Use with caution; consider lower initial doses

Liver Dose Adjustments


  • Severe hepatic insufficiency: Use with caution, consider lower initial doses

Dose Adjustments

Reduced dosages should be considered in patients receiving concomitant narcotics analgesics, general anesthetics, phenothiazines, tranquilizers, sedative-hypnotics, tricyclic antidepressants, barbiturates, alcohol, or other CNS depressants. The dose of concomitant barbiturates should be reduced by at least one-half and of morphine by one-fourth to one-half.

Dose selection for elderly patients should be cautious and start at the low end of the dosing range.

Do not abruptly discontinue in a physically dependent patient.



  • Addiction, Abuse, and Misuse: This drug exposes patients and other users to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death. Assess each patient's risk prior to prescribing and monitor all patients regularly for the development of these behaviors or conditions.
  • Life-Threatening Respiratory Depression: Serious, life-threatening, or fatal respiratory depression may occur. Monitor for respiratory depression, especially during initiation or following a dose increase.
  • Neonatal Opioid Withdrawal Syndrome: Prolonged use during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. If opioid use is required for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure appropriate treatment be available.
  • CYP450 3A4 Interaction: Concomitant use with all CYP450 3A4 inhibitors may result in an increase in plasma concentrations, which could increase or prolong adverse drug effects and may cause potentially fatal respiratory depression. Additionally, discontinuation of a concomitantly used CYP450 3A4 inducer may result in an increase in plasma concentrations. Monitor patients receiving any CYP450 3A4 inhibitor or inducer.
  • Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants: Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of meperidine and benzodiazepines or other CNS depressants for use in patients for whom alternative treatment options are inadequate; limit dosages and durations to the minimum required; and follow patients for signs and symptoms of respiratory depression and sedation.
  • Concomitant use with Monoamine Oxidase Inhibitors (MAOIs): Concomitant use with MAOIs can result in coma, severe respiratory depression, cyanosis, and hypotension. Use of meperidine with MAOIs within last 14 days is contraindicated.

PROMETHAZINE should not be used in pediatric patients less than 2 years of age because of the potential for fatal respiratory depression.
  • Postmarketing cases of respiratory depression, including fatalities, have been reported with use of promethazine in pediatric patients less than 2 years of age. A wide range of weight-based doses of promethazine have resulted in respiratory depression in these patients.
  • It is recommended that the lowest effective dose be used and concomitant administration of other drugs with respiratory depressant effects be avoided.

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

US Controlled Substance: Schedule II


Data not available

Other Comments

Administration advice:

  • Take orally as directed

Parenteral product is currently not being marketed

  • The American Pain Society (APS) does not recommend use of oral meperidine as an analgesic agent due to the extensive amount of neurotoxic metabolite produced relative to the analgesic dose delivered; APS recommends avoiding analgesic use in those with acute vaso-occlusive crisis pain associated with sickle-cell disease, and patients with renal impairment.
  • Dosing regimens should be individualized taking into account pain severity, prior analgesic treatment experience, and risk factors for addiction, abuse, and misuse; the goal of therapy should be the lowest effective dose for the shortest duration consistent with individual patient goals; this drug is not indicated for the treatment of chronic pain.
  • Black box warning includes warnings on addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion, neonatal opioid withdrawal syndrome; CYP450 3A4 interaction; risks from concomitant use with benzodiazepines or other CNS depressants, and MAOI inhibitor interactions.

  • Assess risks for addiction, abuse, and misuse prior to therapy and regularly assess for development of these behaviors during therapy.
  • Monitor for respiratory depression, especially within the first 24 to 72 hours of initiating therapy and following dose increases.
  • Monitor for signs of hypotension upon initiating therapy and following dose increases, especially if blood pressure is already compromised.
  • Monitor patients with biliary tract disease, including pancreatitis, for worsening symptoms

Patient advice:
  • Advise patients to store this drug safely out of the sight and reach of children; accidental use by a child is a medical emergency and can result in death.
  • Patients should understand that this drug, even when taken as recommended can result in addiction, abuse, and misuse; instruct patients not to share their drug with others and protect their drug from theft or misuse.
  • Patients should understand the risks of life-threatening respiratory depression, and be informed as to when this risk is greatest.
  • Patients should be instructed to check with their healthcare provider before taking any new medications, including alcohol, herbal supplements and over the counter products.
  • Patients should be advised that this drug may cause drowsiness, dizziness, or impair thinking or motor skills and patients should avoid driving or operating machinery until adverse effects are determined.
  • Patients should be advised to avoid prolonged sun exposure and report any involuntary muscle movements.
  • Women of child bearing potential should understand that prolonged use during pregnancy can result in neonatal opioid withdrawal syndrome and that prompt recognition and treatment will be necessary.
  • Patients should be instructed in proper disposal.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.