FDA label fc01cb97-4b1c-4f4f-baed-401357b05489

WARNINGS Hepatotoxicity Pentazocine hydrochloride and acetaminophen tablets contain acetaminophen and pentazocine hydrochloride. Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4000 milligrams per day, often involve more than one acetaminophen-containing product. The excessive intake of acetaminophen may be intentional to cause self-harm or unintentional as patients attempt to obtain more pain relief or unknowingly take other acetaminophen-containing products. The risk of acute liver failure is higher in individuals with underlying liver disease and in individuals who ingest alcohol while taking acetaminophen. Instruct patients to look for acetaminophen or APAP on package labels and not to use more than one product that contains acetaminophen. Instruct patients to seek medical attention immediately upon ingestion of more than 4000 milligrams of acetaminophen per day, even if they feel well. 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 emergent medical attention. Instruct patients to discontinue pentazocine hydrochloride and acetaminophen tablets immediately and seek medical care if they experience these symptoms. Do not prescribe pentazocine hydrochloride and acetaminophen tablets for patients with acetaminophen allergy. Drug Dependence Pentazocine can cause a physical and psychological dependence. (See DRUG ABUSE AND DEPENDENCE .) Use In Head Injury and Increased Intracranial Pressure In the presence of head injury, intracranial lesions or a preexisting increase in intracranial pressure, the possible respiratory depressant effects of pentazocine and its potential to elevate cerebrospinal fluid pressure (resulting from vasodilation following CO2 retention) may be markedly increased. Furthermore, pentazocine can produce effects on pupillary response and consciousness, which may obscure neurologic signs of further increases in intracranial pressure in patients with head injuries. In such patients, pentazocine hydrochloride and acetaminophen tablets must be used with extreme caution and only if its use is deemed essential. Interactions with Alcohol and Drugs of Abuse Pentazocine may be expected to have additive effects when used in conjunction with alcohol, other opioids, or illicit drugs that cause central nervous system depression because respiratory depression, hypotension, profound sedation, coma or death may result. Patients Receiving Narcotics Pentazocine is a mild narcotic antagonist. Some patients previously given narcotics, including methadone for the daily treatment of narcotic dependence, have experienced withdrawal symptoms after receiving pentazocine. Respiratory Depression Respiratory depression occurs more frequently in elderly or debilitated patients and in those suffering from conditions accompanied by hypoxia, hypercapnia, or upper airway obstruction, in whom even moderate therapeutic doses may significantly decrease pulmonary ventilation. Use pentazocine hydrochloride and acetaminophen tablets with extreme caution in patients with chronic obstructive pulmonary disease or cor pulmonale and in patients having a substantially decreased respiratory reserve (e.g., severe kyphoscoliosis), hypoxia, hypercapnia, or pre-existing respiratory depression. Alternative non-opioid analgesics should be considered, and pentazocine hydrochloride and acetaminophen tablets should be employed only under careful medical supervision at the lowest effective dose in such patients. Acute CNS Manifestations Patients receiving therapeutic doses of pentazocine hydrochloride and acetaminophen tablets have experienced hallucinations (usually visual), disorientation, and confusion which have cleared spontaneously within a period of hours. The mechanism of this reaction is not known. Such patients should be closely observed and vital signs checked. If the drug is reinstituted, it should be done with caution since these acute CNS manifestations may recur.

ADVERSE REACTIONS Clinical experience with pentazocine hydrochloride and acetaminophen tablets have been insufficient to define all possible adverse reactions with this combination. However, reactions reported after oral administration of pentazocine hydrochloride in 50 mg dosage include the following: Cardiovascular: hypertension, hypotension, circulatory depression, tachycardia. Respiratory: rarely respiratory depression, Acute CNS Manifestations: Hallucinations (usually visual), disorientation, and confusion Other CNS effects: grand mal convulsions, increase in intracranial pressure, dizziness, lightheadedness, hallucinations, sedation, euphoria, headache, confusion, disorientation; infrequently weakness, disturbed dreams, insomnia, syncope, and depression; and rarely tremor, irritability, excitement, tinnitus. Autonomic: sweating; infrequently flushing; and rarely chills. Gastrointestinal: nausea, vomiting, constipation; diarrhea, anorexia, dry mouth, Biliary tract spasm, and rarely abdominal distress. Allergic: edema of the face, anaphylactic shock, dermatitis including pruritus, flushed skin including plethora, infrequently rash; and rarely urticaria. Ophthalmic: visual blurring and focusing difficulty, miosis. Hematologic: depression of white blood cells (especially granulocytes) with rare cases of agranulocytosis, which is usually reversible, moderate transient eosinophilia. Dependence and Withdrawal Symptoms: (See WARNINGS , PRECAUTIONS , and DRUG ABUSE AND DEPENDENCE Sections). Other: urinary retention, paresthesia, serious skin reactions, including erythema multiforme, Stevens-Johnson Syndrome, toxic epidermal necrolysis, and alterations in rate or strength of uterine contractions during labor. A few cases of hypersensitivity to acetaminophen have been reported, as manifested by anaphylaxis, angioneurotic edema, thrombocytopenic purpura, skin rashes, and rarely hemolytic anemia and agranulocytosis. Occasionally individuals respond to ordinary doses with nausea and vomiting and diarrhea.