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Codeine Side Effects

Not all side effects for codeine may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

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

In addition to its needed effects, some unwanted effects may be caused by codeine. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when 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
  • shortness of breath
  • stopping of the heart
  • sweating
  • unconsciousness
  • unusual tiredness or weakness
  • vomiting
  • wheezing
  • yellow eyes or skin

If any of the following symptoms of overdose occur while taking codeine, get emergency help immediately:

Symptoms of overdose
  • Bluish lips or skin
  • change in consciousness
  • chest pain or discomfort
  • constricted, pinpoint, or small pupils (black part of the eye)
  • decreased awareness or responsiveness
  • extreme sleepiness or unusual drowsiness
  • loss of consciousness
  • no blood pressure or pulse
  • severe sleepiness
  • slow or irregular heartbeat

Some of the side effects that can occur with codeine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common
  • Drowsiness
  • relaxed and calm
Incidence not known
  • Abdominal or stomach pain or cramps
  • blurred or loss of vision
  • 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 skin
  • night blindness
  • overbright appearance of lights
  • redness of the skin
  • sensation of spinning
  • shakiness
  • skin rash
  • sleeplessness
  • trouble sleeping
  • tunnel vision
  • unable to sleep
  • 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. "Multum Information Services, Inc. Expert Review Panel"

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

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

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

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.