Promethazine/Dextromethorphan

Promethazine/Dextromethorphan is a prescription medication used to treat cough and upper respiratory tract symptoms associated with allergy or the common cold.

• Promethazine/Dextromethorphan is available under the following different brand names: Promethazine DM.

Adult and pediatric dosage

Oral syrup

• (6.25/15mg)/5mL

Cough

Adult dosage

• 5mL (6.25 mg/15mg) orally every 4-6 hours as needed
• Maximum: 30 mL/24 hours

Pediatric dosage

• Children younger than 2 years of age: Contraindicated
• Children 2-6 years: 1.25-2.5 ml orally every 4-6 hours, up to 12.5 mg/30 mg (10 mL) in 24 hours
• Children 6-12 years: 2.5-5 mL orally every 4-6 hours, up to 25 mg/60 mg (20 mL) in 24 hours
• Children 12 years or older: 6.25 mg/15 mg (5 mL) orally every 4-6 hours as needed, not to exceed 30 mL/24 hours

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”.

Common side effects of Promethazine/Dextromethorphan include:

• drowsiness, 
• dizziness, 
• double vision, 
• nervousness, 
• dry mouth,
• ringing in ears
• increased sensitivity to light 
• tiredness, and
• sleeping problems (insomnia)

Serious side effects of Promethazine/Dextromethorphan include:

• hives, 
• difficulty breathing, 
• swelling in the face, lips, tongue, or throat, 
• severe drowsiness, 
• weak or shallow breathing, 
• lightheadedness, 
• confusion, 
• agitation, 
• hallucinations, 
• nightmares, 
• seizures (convulsions), 
• fast or slow heartbeats, 
• yellowing of the skin or eyes (jaundice), 
• uncontrolled muscle movements in the face (chewing, lip-smacking, frowning, tongue movement, blinking or eye movement), 
• easy bruising, 
• unusual bleeding (nosebleeds, bleeding gums), 
• sudden weakness, 
• ill-feeling,  
• fever, 
• chills, 
• sore throat, 
• mouth sores, 
• red or swollen gums, 
• trouble swallowing, 
• very stiff (rigid) muscles, 
• high fever, 
• sweating, 
• fast or uneven heartbeats, 
• tremors, and
• lightheadedness 

Rare side effects of Promethazine/Dextromethorphan include:

• none 

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

• Promethazine/Dextromethorphan has severe interactions with no other drugs.
• Promethazine/Dextromethorphan has serious interactions with no other drugs.
• Promethazine/Dextromethorphan has moderate interactions with no other drugs.
• Promethazine/Dextromethorphan has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

Contraindications

Promethazine

• Hypersensitivity
• Newborn/premature infants, children younger than 2 years (risk of potentially fatal respiratory depression)
• Subcutaneous or intra-arterial administration
• BPH
• Narrow-angle glaucoma
• Pyloroduodenal obstruction, stenosing peptic ulcer, bladder neck obstruction
• Severe CNS depression
• Coma, Severe respiratory depression

Dextromethorphan

• Concurrent nonselective MAO inhibitors: serotonin syndrome

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Promethazine/Dextromethorphan?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Promethazine/Dextromethorphan?”

Cautions

• Promethazine
• CVD, asthma, hepatic impairment, peptic ulcer, respiratory impairment
• Anaphylaxis in susceptible individuals
• May impair ability to drive or perform hazardous tasks
• Monitor closely in patients with
  • Cardiovascular disease
  • Hepatic impairment
  • Reye syndrome
  • History of sleep apnea
• Depresses hypothalamic thermoregulatory mechanism; exposure to extreme temperatures may cause hypo- or hyperthermia
• The antiemetic effect may obscure the toxicity of chemotherapeutic drugs

Dextromethorphan

• Phenylketonuria: Contains aspartame

Pregnancy and Lactation

• Use in pregnancy with caution if benefits outweigh risks. 
• Lactation: Not recommended.