Codeine / Promethazine Side Effects

Medically reviewed by Drugs.com. Last updated on Jun 22, 2023.

Applies to codeine / promethazine: oral solution, oral syrup.

Precautions

It is very important that your doctor check your or your child's progress while taking this medicine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

If your condition does not improve or becomes worse, check with your doctor.

Codeine is changed to morphine in the body. Some people change codeine to morphine more quickly than others. These individuals are called "ultra-rapid metabolizers of codeine". Contact your doctor immediately if you experience extreme sleepiness, confusion, or shallow breathing. These symptoms may indicate that you are an "ultra-rapid metabolizer of codeine". As a result, there may be too much morphine in the body and more side effects from morphine than usual. Children may be especially sensitive to this effect. Do not give this medicine to:

• Children younger than 12 years of age.
• Children younger than 18 years of age who have had surgery removal of tonsils or adenoids.
• Children 12 to 18 years of age who have a high risk for breathing problems (eg, obstructive sleep apnea, obesity, lung disease).

If a nursing mother is an ultra-rapid metabolizer of codeine, it could lead to morphine overdose in the nursing baby and cause very serious side effects.

For nursing mothers taking this medicine:

• Talk to your doctor if you have any questions about taking codeine or about how this medicine may affect your baby.
• Call your doctor if you become extremely tired and have difficulty caring for your baby.
• Your baby should generally nurse every 2 to 3 hours and should not sleep for more than 4 hours at a time.
• Check with your doctor or hospital emergency room immediately if your baby shows signs of increased sleepiness (more than usual), difficulty breastfeeding, difficulty breathing, or limpness. These may be symptoms of an overdose and need immediate medical attention.

This medicine may be habit-forming. If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.

Using narcotics for a long time can cause severe constipation. To prevent this, your doctor may direct you to take laxatives, drink a lot of fluids, or increase the amount of fiber in your diet. Be sure to follow the directions carefully, because continuing constipation can lead to more serious problems.

This medicine may cause some people to become dizzy, drowsy, or less alert than they are normally. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. You may also feel lightheaded when getting up suddenly from a lying or sitting position, so stand up slowly.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, allergies, or colds, sedatives, tranquilizers, or sleeping medicine, prescription pain medicine or narcotics, medicine for seizures or barbiturates, or anesthetics, including some dental anesthetics. Check with your medical doctor or dentist before taking any of the above while you or your child are using this medicine.

Promethazine may increase your risk for convulsions (seizures). It may also cause dystonia (movement disorder). This is more likely in sick children with diarrhea. Talk to your doctor if you have any concerns.

Check with your doctor right away if you or your child are having convulsions, difficulty in breathing, fast heartbeat, high fever, high or low blood pressure, increased sweating, loss of bladder control, severe muscle stiffness, unusually pale skin, or tiredness. These could be symptoms of a serious condition called neuroleptic malignant syndrome (NMS).

If you think you or your child may have taken an overdose of this medicine, get emergency help at once. Signs of an overdose include extreme sleepiness, confusion, shallow breathing, hallucinations, nausea, vomiting, pinpoint pupils of the eyes, pale or blue lips, fingernails, or skin, or seizures.

Before you have any medical tests, tell the medical doctor in charge that you or your child are taking this medicine. The results of some tests may be affected by this medicine.

This medicine may make your skin more sensitive to sunlight. Use sunscreen when you are outdoors. Avoid sunlamps and tanning beds.

This medicine may cause dryness of the mouth. For temporary relief, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects

Along with its needed effects, codeine / promethazine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking codeine / promethazine:

Get emergency help immediately if any of the following symptoms of overdose occur while taking codeine / promethazine:

Symptoms of overdose

• cold, clammy skin
• dry mouth
• fainting
• no blood pressure or pulse
• no muscle tone or movement
• pinpoint pupils (black part of the eye)
• stopping of the heart
• unconsciousness

Other side effects

Some side effects of codeine / promethazine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to codeine / promethazine: oral syrup.

General adverse events

The more commonly reported adverse effects have included nausea, vomiting, constipation, blurred vision, confusion, and dizziness.^[Ref]

Respiratory

Codeine:

• Frequency not reported: Respiratory depression

Promethazine:

• Frequency not reported: Asthma, nasal stuffiness, respiratory depression, apnea^[Ref]

Concomitant administration of promethazine with other respiratory depressants has been associated with respiratory depression, including fatalities. Postmarketing cases in pediatric patients less than 2 years of age has been reported with a wide range of weight-based doses. Respiratory depression has been associated with antitussive use of codeine in young children.

Respiratory depression and death have occurred in children who received codeine in the postoperative period following tonsillectomy and/or adenoidectomy. Further investigation has shown these patients to be ultra-rapid metabolizers of codeine. Children with obstructive sleep apnea who are treated with codeine appear to be particularly sensitive to the respiratory depressant effects of codeine.^[Ref]

Nervous system

• Frequency not reported: CNS depression, lightheadedness, dizziness, sedation, headache, convulsions, weakness

Promethazine:

• Frequency not reported: Drowsiness, sedation, somnolence, extra-pyramidal symptoms, torticollis, tongue protrusion, incoordination, tremors, seizures, neuroleptic malignant syndrome, paradoxical reactions^[Ref]

Promethazine use has resulted in paradoxical reactions described as hyperexcitability and abnormal movements. This has occurred following 1 dose and in some patients accompanied by respiratory depression, nightmares, delirium, and agitated behavior.^[Ref]

Codeine

Psychiatric

• Frequency not reported: Euphoria, dysphoria, transient hallucination, disorientation

Promethazine:

• Frequency not reported: Confusion, disorientation, euphoria, nervousness, insomnia, excitation, catatonic-like states, hysteria, hallucinations^[Ref]

Codeine

Gastrointestinal

• Frequency not reported: Nausea, vomiting, constipation, biliary tract spasm, increased colonic motility, toxic dilation

Promethazine:

• Frequency not reported: Dry mouth, nausea, vomiting^[Ref]

Patients with chronic ulcerative colitis may experience increased colonic motility, while patients with acute ulcerative colitis have experienced toxic dilation with codeine use.^[Ref]

Codeine

Hypersensitivity

• Frequency not reported: Pruritus, giant urticaria, angioneurotic edema, laryngeal edema

Promethazine:

• Frequency not reported: Angioneurotic edema^[Ref]

Codeine

Cardiovascular

• Frequency not reported: Tachycardia, bradycardia, palpitation, faintness, syncope, orthostatic hypotension, circulatory depression

Promethazine:

• Frequency not reported: Increased or decreased blood pressure, tachycardia, bradycardia, faintness^[Ref]

Codeine

Genitourinary

• Frequency not reported: Oliguria, urinary retention, antidiuretic effect^[Ref]

Codeine

Dermatologic

Promethazine:

• Frequency not reported: Dermatitis, photosensitivity, urticaria^[Ref]

Hematologic

Promethazine:

• Frequency not reported: Leukopenia, thrombocytopenia, thrombocytopenic purpura, agranulocytosis^[Ref]

Hepatic

Promethazine:

• Frequency not reported: Cholestatic jaundice^[Ref]

Metabolic

Promethazine:

• Frequency not reported: Hyperglycemia

Ocular

• Frequency not reported: Visual disturbances

Promethazine:

• Frequency not reported: Blurred vision, oculogyric crisis, diplopia^[Ref]

Codeine

Other

Promethazine:

• Frequency not reported: Lassitude, tinnitus, fatigue^[Ref]

See also:

Further information

Codeine/promethazine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer