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Codrix Side Effects

Generic Name: acetaminophen / codeine

Note: This page contains information about the side effects of acetaminophen / codeine. Some of the dosage forms included on this document may not apply to the brand name Codrix.

For the Consumer

Applies to acetaminophen / codeine: oral capsule, oral elixir, oral solution, oral suspension, oral tablet

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

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking acetaminophen / codeine:

More common:
  • Difficult or troubled breathing
  • irregular, fast or slow, or shallow breathing
  • pale or blue lips, fingernails, or skin
  • shortness of breath
Incidence not known:
  • Black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • cough or hoarseness
  • difficulty with swallowing
  • dizziness
  • fast heartbeat
  • fever with or without chills
  • general feeling of tiredness or weakness
  • hives
  • itching
  • lower back or side pain
  • painful or difficult urination
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • skin rash
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • tightness in the chest
  • unusual bleeding or bruising
  • unusual tiredness or weakness

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

Symptoms of overdose:
  • Abdominal or stomach pain
  • bloody or cloudy urine
  • chills
  • constricted, pinpoint, or small pupils (black part of the eye)
  • convulsions
  • dark urine
  • headache
  • increased sweating
  • light-colored stools
  • loss of appetite
  • loss of consciousness
  • nausea
  • sudden decrease in amount of urine
  • unpleasant breath odor
  • vomiting
  • vomiting of blood
  • yellow eyes or skin

Minor Side Effects

Some of the side effects that can occur with acetaminophen / 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
  • lightheadedness
  • relaxed and calm
  • sleepiness
Incidence not known:
  • Difficulty having a bowel movement (stool)
  • false or unusual sense of well-being

For Healthcare Professionals

Applies to acetaminophen / codeine: oral capsule, oral liquid, oral suspension, oral tablet


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

Nervous system

Common (1% to 10%): Drowsiness, dizziness
Frequency not reported: Lightheadedness, sedation, medication over-use headache

Frequency not reported: Drowsiness, impaired mental functions

Frequency not reported: Confusion, drowsiness, vertigo, dizziness, CNS excitation (restlessness/excitement), convulsions, headache, raised intracranial pressure[Ref]


Frequency not reported: Nausea, vomiting, constipation, abdominal pain

Very rare (less than 0.01%): Pancreatitis
Frequency not reported: Dyspepsia

Frequency not reported: Constipation, GI irritation, biliary spasm, nausea, vomiting, loss of appetite, dry mouth, paralytic ileus, toxic megacolon[Ref]


Frequency not reported: Acute liver failure, hepatotoxicity, chronic hepatic necrosis, cytolytic hepatitis[Ref]


Frequency not reported: Euphoria, dysphoria

Frequency not reported: Confusion, changes in mood, hallucinations, mental depression, trouble sleeping or nightmares, tolerance or dependence[Ref]


Frequency not reported: Renal failure, uremia

Frequency not reported: Nephrotoxicity, papillary necrosis[Ref]


Frequency not reported: Allergic reactions

Rare (less than 0.1%): Allergic reactions including skin rash, drug fever, mucosal lesions
Postmarketing reports: Hypersensitivity including swelling of the face, mouth, and throat, respiratory distress, urticaria, rash, pruritus, and vomiting, anaphylaxis, angioedema

Frequency not reported: Rash, urticaria, difficulty breathing, increased sweating, redness, redness or flushed face[Ref]


Frequency not reported: Toxic myocarditis, Kounis syndrome

Frequency not reported: Bradycardia, palpitations, hypotension[Ref]


Frequency not reported: Urinary retention or hesitance

Frequency not reported: Urinary retention, ureteral spasm, antidiuretic effect[Ref]


Frequency not reported: Thrombocytopenia, agranulocytosis, anemia

Very rare (less than 0.01%): Thrombocytopenia, neutropenia, leucopenia
Frequency not reported: Agranulocytosis, methemoglobinemia, pancytopenia, thrombocytopenia purpura, hemolytic anemia[Ref]


Frequency not reported: Pruritus, rash

Rare (less than 0.1%): Serious skin reactions such as acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN)
Frequency not reported: Sweating, fixed drug eruption[Ref]


In patients with a tendency of analgesic asthma acetaminophen-use has triggered bronchospasms.[Ref]

Frequency not reported: Shortness of breath

Frequency not reported: Bronchospasm

Frequency not reported: Respiratory depression[Ref]


Frequency not reported: Blurred or double vision[Ref]


1. "Product Information. Acetaminophen-Codeine Phosphate (acetaminophen-codeine)." Qualitest Pharmaceuticals Inc, Huntsville, ON.

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

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

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

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.