Acetaminophen and Codeine Phosphate (Page 5 of 11)

Interaction with Monoamine Oxidase Inhibitors

Monoamine oxidase inhibitors (MAOIs) may potentiate the effects of morphine, codeine’s active metabolite including respiratory depression, coma, and confusion. Acetaminophen and codeine phosphate oral solution should not be used in patients taking MAOIs or within 14 days of stopping such treatment.

Adrenal Insufficiency

Cases of adrenal insufficiency have been reported with opioid use, more often following greater than 1 month of use. Presentation of adrenal insufficiency may include non-specific symptoms and signs including nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure. If adrenal insufficiency is suspected, confirm the diagnosis with diagnostic testing as soon as possible. If adrenal insufficiency is diagnosed, treat with physiologic replacement doses of corticosteroids. Wean the patient off of the opioid to allow adrenal function to recover and continue corticosteroid treatment until adrenal function recovers. Other opioids may be tried as some cases reported use of a different opioid without recurrence of adrenal insufficiency. The information available does not identify any particular opioids as being more likely to be associated with adrenal insufficiency.

Severe Hypotension

Acetaminophen and codeine phosphate oral solution may cause severe hypotension including hypotension and syncope in ambulatory patients. There is increased risk in patients whose ability to maintain blood pressure has already been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (e.g., phenothiazines or general anesthetics) [see PRECAUTIONS; Drug Interactions]. Monitor these patients for signs of hypotension after initiating or titrating the dosage of acetaminophen and codeine phosphate oral solution. In patients with circulatory shock acetaminophen and codeine phosphate oral solution may cause vasodilatation that can further reduce cardiac output and blood pressure. Avoid the use of acetaminophen and codeine phosphate oral solution with circulatory shock.

Serious Skin Reactions

Rarely, acetaminophen may cause serious skin reactions such as acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. Patients should be informed about the signs of serious skin reactions, and use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.

Risks of Use in Patients with Increased Intracranial Pressure, Brain Tumors, Head Injury, or Impaired Consciousness

In patients who may be susceptible to the intracranial effects of CO₂ retention (e.g., those with evidence of increased intracranial pressure or brain tumors), acetaminophen and codeine phosphate oral solution may reduce respiratory drive, and the resultant CO₂ retention can further increase intracranial pressure. Monitor such patients for signs of sedation and respiratory depression, particularly when initiating therapy with acetaminophen and codeine phosphate oral solution.

Opioids may also obscure the clinical course in a patient with a head injury. Avoid the use of acetaminophen and codeine phosphate oral solution in patients with impaired consciousness or coma.

Hypersensitivity/Anaphylaxis

There have been post-marketing reports of hypersensitivity and anaphylaxis associated with use of acetaminophen. Clinical signs included swelling of the face, mouth, and throat, respiratory distress, urticaria, rash, pruritus, and vomiting. There were infrequent reports of life-threatening anaphylaxis requiring emergency medical attention. Instruct patients to discontinue acetaminophen and codeine phosphate oral solution immediately and seek medical care if they experience these symptoms. Do not prescribe acetaminophen and codeine phosphate oral solution for patients with acetaminophen allergy [see PRECAUTIONS; Information for Patients/Caregivers].

Risks of Use in Patients with Gastrointestinal Conditions

Acetaminophen and codeine phosphate oral solution is contraindicated in patients with gastrointestinal obstruction, including paralytic ileus.

The administration of acetaminophen and codeine phosphate oral solution or other opioids may obscure the diagnosis or clinical course in patients with acute abdominal conditions.

Acetaminophen and codeine phosphate oral solution may cause spasm of the sphincter of Oddi. Opioids may cause increases in serum amylase. Monitor patients with biliary tract disease, including acute pancreatitis, for worsening symptoms.

Increased Risk of Seizures in Patients with Seizure Disorders

The codeine in acetaminophen and codeine phosphate oral solution may increase the frequency of seizures in patients with seizure disorders, and may increase the risk of seizures occurring in other clinical settings associated with seizures. Monitor patients with a history of seizure disorders for worsened seizure control during acetaminophen and codeine phosphate oral solution therapy.

Withdrawal

Do not abruptly discontinue acetaminophen and codeine phosphate oral solution in a patient physically dependent on opioids. When discontinuing acetaminophen and codeine phosphate oral solution in a physically dependent patient, gradually taper the dosage. Rapid tapering of acetaminophen and codeine phosphate oral solution in a patient physically dependent on opioids may lead to a withdrawal syndrome and return of pain [see DOSAGE AND ADMINISTRATION, DRUG ABUSE AND DEPENDENCE]

Additionally, avoid the use of mixed agonist/antagonist (e.g., pentazocine, nalbuphine, and butorphanol) or partial agonist (e.g., buprenorphine) analgesics in patients who are receiving a full opioid agonist analgesic, including acetaminophen and codeine phosphate oral solution. In these patients, mixed agonist/antagonist and partial agonist analgesics may reduce the analgesic effect and/or precipitate withdrawal symptoms [see PRECAUTIONS; Drug Interactions].

PRECAUTIONS

Risks of Driving and Operating Machinery

Acetaminophen and codeine phosphate oral solution may impair the mental or physical abilities needed to perform potentially hazardous activities such as driving a car or operating machinery. Warn patients not to drive or operate dangerous machinery unless they are tolerant to the effects of acetaminophen and codeine phosphate oral solution and know how they will react to the medication [see PRECAUTIONS; Information for Patients/Caregivers].

Information for Patients

Advise the patient to read the FDA-approved patient labeling (Medication Guide).

Medication Errors

Instruct patients how to measure and take the correct dose of acetaminophen and codeine phosphate oral solution, and ensure that the dose is communicated clearly and dispensed accurately. A household teaspoon is not an adequate measuring device. Given the inexactitude of the household spoon measure and the risk of using a tablespoon instead of a teaspoon, which could lead to overdosage, it is strongly recommended that caregivers obtain and use a calibrated measuring device. Healthcare providers should recommend a calibrated device that can measure and deliver the prescribed dose accurately, and instruct caregivers to use extreme caution in measuring the dosage and when administering acetaminophen and codeine phosphate oral solution to ensure the dose is measured and administered accurately [see WARNINGS].

If the prescribed concentration is changed, instruct patients on how to correctly measure the new dose to avoid errors which could result in accidental overdose and death.

Addiction, Abuse, and Misuse

Inform patients that the use of acetaminophen and codeine phosphate oral solution, even when taken as recommended, can result in addiction, abuse, and misuse, which can lead to overdose and death [see WARNINGS]. Instruct patients not to share acetaminophen and codeine phosphate oral solution with others and to take steps to protect acetaminophen and codeine phosphate oral solution from theft or misuse.

Life-Threatening Respiratory Depression

Inform patients of the risk of life-threatening respiratory depression, including information that the risk is greatest when starting acetaminophen and codeine phosphate oral solution or when the dosage is increased, and that it can occur even at recommended dosages [see WARNINGS]. Advise patients how to recognize respiratory depression and to seek medical attention if breathing difficulties develop.

Accidental Ingestion

Inform patients that accidental ingestion, especially by children, may result in respiratory depression or death [see WARNINGS].