promethazine and codeine, Phenergan with Codeine

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

What is the dosage for promethazine and codeine?

The usual adult dose is one teaspoonful every 4 to 6 hours as needed. The maximum dose is two tablespoons daily.

Which drugs or supplements interact with promethazine and codeine?

Excessive sedation may occur when promethazine and codeine is combined with other medications that cause sedation. Such drugs include ethanol, barbiturates, anti-anxiety medications, sedatives, other phenothiazines, and narcotic pain medications.

Promethazine should not be taken with any of the monoamine oxidase (MAO) inhibitor class of antidepressants, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane), because of the increased risk of extrapyramidal symptoms (EPS) - uncontrollable movement disorders. Excessive anti-cholinergic effects (described below) can occur when promethazine is used with other antihistamines, for example, diphenhydramine (Benadryl), some phenothiazines, for example, thioridazine,  some tricyclic antidepressants, for example, amitriptyline, clozapine (Clozaril, FazaClo, Versacloz), cyclobenzaprine (Active-Cyclobenzaprine, Amrix, EnovaRX-Cyclobenzaprine HCl, Fexmid)), and disopyramide (Norpace).

There may be an increase in the risk of certain neurologic reactions that affect movement of muscles (EPS, see below) when promethazine is combined with medicines that also cause EPS. Such drugs include antipsychotics, metoclopramide (Metozolv ODT, Reglan), and amoxapine.

Promethazine should not be used with propylthiouracil (PTU) due to the increased risk of low white blood cell counts and increased risk of infections. The reason for this interaction is not known.

Concurrent use of promethazine with the dye used for myelography (X-rays of the spinal cord) can lower the threshold for seizures and thus increase the risk of seizures. Promethazine should be stopped at least 48 hours before myelography and not restarted until at least 24 hours after myelography.

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