Is Promethazine-DM the same as codeine?

Promethazine-DM and codeine are two different medications that are commonly used to treat coughs, colds, allergies, and other respiratory conditions. While they share some similarities, there are important differences between these two drugs that patients should understand before taking either medication.

What is Promethazine-DM?

Promethazine-DM is an over-the-counter (OTC) cough and cold medication that contains two active ingredients – promethazine and dextromethorphan (DM).

Promethazine belongs to a class of drugs called phenothiazines. It works as an antihistamine, blocking the effects of histamine in the body and relieving symptoms like sneezing, runny nose, watery eyes, and itching. Promethazine also has sedative effects that can help suppress coughing.

Dextromethorphan (DM) is a cough suppressant that works by depressing the cough reflex in the brain. It provides temporary relief for coughing without affecting mucus production.

Together, the promethazine and DM in Promethazine-DM treat multiple cold and allergy symptoms. Promethazine addresses sneezing, runny nose, and itching, while DM relieves coughing. The promethazine also potentiates the effects of the DM, increasing cough suppression.

What is Codeine?

Codeine is a prescription opioid medication that is often combined with other drugs in prescription cough and cold medicines. It is a narcotic pain reliever and cough suppressant.

As an opioid drug, codeine works by binding to opioid receptors in the brain, spinal cord, and gastrointestinal tract. This blocks pain signals and the cough reflex. The effects of codeine both reduce pain and suppress cough.

Most codeine-containing cough and cold medicines also contain other drugs such as antihistamines or decongestants. For example, promethazine with codeine combines codeine with promethazine.

Key Differences

While Promethazine-DM and codeine can both be found in some cough and cold preparations, there are important distinctions between these two medications:

  • Promethazine-DM is available over-the-counter, while codeine requires a prescription.
  • Promethazine-DM is not an opioid or narcotic, whereas codeine is an opioid.
  • Promethazine-DM only treats symptoms associated with colds or allergies. Codeine treats cough but also provides pain relief.
  • Promethazine-DM causes drowsiness but codeine has more potent sedative effects.
  • Codeine has a much higher potential for abuse and addiction.

Side Effects

Promethazine-DM and codeine share some similar side effects, but codeine is more likely to cause serious reactions. Possible side effects of Promethazine-DM include:

  • Drowsiness
  • Dizziness
  • Dry mouth and throat
  • Nausea
  • Weakness
  • Nervousness

Codeine can cause all the above side effects as well as:

  • Severe drowsiness and sedation
  • Confusion
  • Constipation
  • Difficulty urinating
  • Slowed or stopped breathing
  • Low blood pressure

Codeine also carries risks of addiction, dependence, tolerance, and withdrawal with long-term use.

Drug Interactions

Both Promethazine-DM and codeine interact with certain other drugs. Promethazine may interact with:

  • Sedatives like benzodiazepines
  • Antidepressants
  • Other antihistamines
  • Sleep aids
  • Alcohol

Codeine also interacts with all of the above. Additionally, codeine shouldn’t be used with other opioid pain medications, muscle relaxants, or sedatives due to an increased risk of dangerous respiratory depression and sedation.

FDA Warnings

The US Food and Drug Administration (FDA) has issued a Drug Safety Communication regarding the use of codeine in children under 12 years old. After safety reviews, the FDA concluded that the risks of using codeine for cough and pain relief in young children outweigh the potential benefits.

The FDA identified a number of reports of codeine toxicity and adverse events like extreme sleepiness, breathing problems, and even death in children who took normal codeine doses. Children may be more susceptible to high morphine levels from codeine use.

As a result, the FDA added a “Boxed Warning” to codeine labeling to strictly limit its use in children. The FDA does not restrict Promethazine-DM in the same way.

Usage in Pregnancy and Breastfeeding

The use of codeine and Promethazine-DM during pregnancy should always be discussed with a doctor first. Codeine is not recommended for use during pregnancy unless the benefits clearly outweigh the risks.

Promethazine is considered relatively safe during pregnancy, especially later on. But in early pregnancy, antihistamines like promethazine might potentially increase risks to the fetus.

For breastfeeding mothers, both codeine and promethazine can transfer to breastmilk and cause drowsiness in nursing infants. Use of either drug while breastfeeding should be monitored closely by a doctor.


Promethazine-DM and codeine are not the same medication. While both can treat cough from colds or allergies, promethazine/DM offers OTC allergy relief while codeine requires a prescription and is a narcotic. Key differences exist between these drugs in their effects, side effects, regulations, safety, and potential for abuse.

Patients should be aware that codeine has more serious risks of side effects, drug interactions, and dependency issues. The FDA also restricts codeine use in young children. In general, Promethazine-DM only treats allergy symptoms while codeine works as a narcotic pain/cough reliever.

When used carefully as directed by a doctor, both can provide relief for respiratory symptoms. But they are separate medications and a doctor should be consulted before taking either drug.

Medication Promethazine-DM Codeine
Type OTC cough & cold medication Prescription opioid narcotic
Uses Allergy symptoms, cough from colds Cough, pain relief
Regulation Over-the-counter Prescription-only

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