Home Drug Guide Acetaminophen and Codeine Phosphate

Drug Guide

Generic Name

Acetaminophen and Codeine Phosphate

Brand Names Codrix, Capital And Codeine, Empracet W/ Codeine Phosphate #3, Empracet W/ Codeine Phosphate #4, Phenaphen W/ Codeine No. 2, Phenaphen W/ Codeine No. 3, Phenaphen W/ Codeine No. 4, Tylenol W/ Codeine No. 1, Tylenol W/ Codeine No. 2, Tylenol W/ Codeine No. 3, Tylenol W/ Codeine No. 4, Tylenol W/ Codeine, Proval #3, Phenaphen-650 W/ Codeine, Papa-deine #3, Papa-deine #4

Classification

Therapeutic: Analgesic, Antitussive

Pharmacological: Opioid analgesic with non-opioid analgesic

FDA Approved Indications

Moderate to severe pain
Cough suppression

Mechanism of Action

Codeine is converted in the liver to morphine, which binds to opioid receptors in the brain and spinal cord to reduce the perception of pain and suppress cough. Acetaminophen works centrally to inhibit pain and reduce fever.

Dosage and Administration

Adult: As prescribed, generally q4-6h as needed, not to exceed daily maximums.

Pediatric: Use with caution; dosing based on weight and age, typically under strict medical supervision.

Geriatric: Adjust dose based on renal/hepatic function, monitor for sedation and respiratory depression.

Renal Impairment: Adjust dose accordingly; may require dose reduction or increased dosing interval.

Hepatic Impairment: Use with caution; acetaminophen metabolism may be impaired, increasing risk of toxicity.

Pharmacokinetics

Absorption: Rapidly absorbed from gastrointestinal tract.

Distribution: Widely distributed, crosses the blood-brain barrier.

Metabolism: Metabolized in the liver; codeine via CYP2D6 to morphine, acetaminophen via conjugation.

Excretion: Excreted primarily in the urine.

Half Life: Approximately 2-4 hours for acetaminophen; 3-4 hours for codeine.

Contraindications

Known hypersensitivity to acetaminophen or codeine.
Respiratory depression, including severe asthma.
Children under 12 years (especially for codeine due to risk of severe respiratory depression).

Precautions

Use with caution in hepatic impairment, respiratory impairment, or in elderly. Monitor for signs of opioid toxicity and hepatotoxicity. Container warning for children due to toxicity risk.

Adverse Reactions - Common

Drowsiness (Common)
Dizziness (Common)
Nausea (Common)

Adverse Reactions - Serious

Respiratory depression (Rare)
Hepatotoxicity (due to acetaminophen overdose) (Rare)
Hypersensitivity reactions including rash (Uncommon)

Drug-Drug Interactions

CNS depressants, other opioids, benzodiazepines, alcohol, fluconazole, zidovudine.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor pain relief, respiratory status, liver function, and signs of opioid toxicity.

Diagnoses:

Risk for respiratory depression
Impaired comfort

Implementation: Administer with food or milk to minimize gastrointestinal upset; monitor for adverse effects.

Evaluation: Assess pain relief, respiratory function, and liver enzymes regularly.

Patient/Family Teaching

Do not operate machinery or drive until effects are known.
Avoid alcohol and CNS depressants.
Report signs of allergic reaction, severe dizziness, difficulty breathing.
Use only as prescribed; do not exceed recommended dosage.

Special Considerations

Black Box Warnings:

Respiratory depression and death in children due to codeine metabolism variability.
Risk of hepatotoxicity due to acetaminophen overdose.

Genetic Factors: CYP2D6 polymorphisms can affect codeine metabolism, leading to variable effects.

Lab Test Interference: May interfere with liver function tests.

Overdose Management

Signs/Symptoms: Nausea, vomiting, sweating, pallor, confusion, hypotension, liver failure, respiratory depression.

Treatment: Administer naloxone for respiratory depression; supportive care; activated charcoal if ingestion is recent; monitor liver function.

Storage and Handling

Storage: Store in a tight container at room temperature away from moisture and heat.

Stability: Stable under recommended storage conditions.