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Codeine Side Effects

For the Consumer

Applies to codeine: oral solution, oral syrup, oral tablet, oral tablet extended release

Along with its needed effects, codeine 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:

Incidence not known
  • Bloating
  • blurred vision
  • chills
  • cold, clammy skin
  • confusion
  • constipation
  • darkened urine
  • difficult or troubled breathing
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • fast, irregular, pounding, or racing heartbeat or pulse
  • fast, weak pulse
  • feeling of warmth
  • fever
  • indigestion
  • irregular, fast or slow, or shallow breathing
  • lightheadedness
  • loss of appetite
  • nausea
  • no blood pressure or pulse
  • no breathing
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pale or blue lips, fingernails, or skin
  • redness of the face, neck, arms, and occasionally, upper chest
  • stopping of the heart
  • sweating
  • unconsciousness
  • unusual tiredness or weakness
  • vomiting
  • yellow eyes or skin

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

Symptoms of overdose
  • Bluish lips or skin
  • chest pain or discomfort
  • constricted, pinpoint, or small pupils (black part of the eye)
  • decreased awareness or responsiveness
  • extreme sleepiness or unusual drowsiness
  • slow or irregular heartbeat

Some side effects of codeine 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:

More common
  • Drowsiness
  • relaxed and calm feeling
Incidence not known
  • Diarrhea
  • disturbed color perception
  • double vision
  • dry mouth
  • false or unusual sense of well-being
  • fear or nervousness
  • feeling of constant movement of self or surroundings
  • halos around lights
  • headache
  • hives or welts, itching, or skin rash
  • night blindness
  • overbright appearance of lights
  • redness of the skin
  • sensation of spinning
  • shakiness
  • stomach pain or cramps
  • trouble sleeping
  • tunnel vision
  • weight loss

For Healthcare Professionals

Applies to codeine: compounding powder, injectable solution, oral solution, oral tablet


The most frequently observed adverse reactions include drowsiness lightheadedness, dizziness, sedation, shortness of breath, nausea, vomiting, sweating, and constipation.[Ref]


Uncommon (0.1% to 1%): Bronchospasm, laryngospasm, respiratory depression
Frequency not reported: Respiratory arrest, dyspnea
Postmarketing reports: Deaths due to respiratory depression[Ref]

Respiratory depression resulting in death has been reported in children who received codeine postoperatively following tonsillectomy and/or adenoidectomy. These children had evidence of being ultra-rapid metabolizers of codeine. Death has also been reported in nursing infants exposed to high levels of morphine in breast milk due to their breastfeeding mother being an ultra-rapid metabolizer of codeine.[Ref]


Uncommon (0.1% to 1%): Heartbeat irregularities, blood pressure changes, syncope
Frequency not reported: Flushing, hypotension, palpitations, circulatory depression, shock, cardiac arrest, circulatory depression, bradycardia, tachycardia, edema[Ref]

Nervous system

Common (1% to 10%): Drowsiness, dizziness
Uncommon (0.1% to 1%): Headache, lightheadedness, feeling faint, paradoxical CNS stimulation (especially in children), disorientation, restlessness, shakiness, somnolence, weakness
Frequency not reported: Seizures[Ref]


Frequency not reported: Fatigue, vertigo, malaise, hypothermia, fever, addiction, tolerance, dependence, withdrawal reactions upon discontinuation of chronically administered drug included diarrhea, sweating, vomiting, insomnia, agitation, tremor, body aches, gooseflesh, loss of appetite, nervousness or restlessness, runny nose, sneezing, shivering, stomach cramps, nausea, sleep disturbances, yawning, weakness, tachycardia, fever, irritability, mydriasis[Ref]


Uncommon (0.1% to 1%): Itching, facial swelling, pruritus, urticaria, histamine release (hypotension, sweating, flushing of the face, tachycardia, breathlessness)
Frequency not reported: Allergic reactions including maculopapular rash[Ref]


Common (1% to 10%): Constipation
Uncommon (0.1% to 1%): Dry mouth, loss of appetite, nausea, vomiting, paralytic ileus, toxic megacolon, anorexia, stomach cramps
Frequency not reported: Gastrointestinal distress, anorexia, diarrhea, pancreatitis[Ref]


Frequency not reported: Biliary spasm[Ref]


Uncommon (0.1% to 1%): Urinary retention or hesitance, ureteric spasm, reduced libido and/or potency[Ref]


Uncommon (0.1% to 1%): Rash
Frequency not reported: Sweating, urticaria, pruritus[Ref]


Uncommon (0.1% to 1%): Miosis, blurred or double vision
Frequency not reported: Visual disturbances[Ref]


Uncommon (0.1% to 1%): Antidiuretic effect
Frequency not reported: Decreased libido or potency, erectile dysfunction, sexual dysfunction[Ref]


Uncommon (0.1% to 1%): Euphoria, dysphoria, unusual dreams, hallucinations, insomnia, anxiety
Frequency not reported: Mood changes, restlessness, confusion, mental depression[Ref]


Frequency not reported: Hyperglycemia, anorexia[Ref]


1. Cerner Multum, Inc. "Australian Product Information." O 0

2. "Multum Information Services, Inc. Expert Review Panel"

3. "Product Information. Codeine Sulfate (codeine)." Roxane Laboratories Inc, Columbus, OH.

4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Some side effects of codeine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.