Tencon Drug Information

Tencon (butalbital and acetaminophen) Tablets are indicated for the relief of the symptom complex of tension (or muscle contraction) headache. Evidence supporting the efficacy and safety of this combination product in the treatment of multiple recurrent headaches is unavailable. Caution in this regard is required because butalbital is habit-forming and potentially abusable.

Oral: One to two tablets every four hours as needed. Total daily dosage should not exceed 6 tablets. Extended and repeated use of this product is not recommended because of the potential for physical dependence.

Frequently Observed The most frequently reported adverse reactions are drowsiness, lightheadedness, dizziness, sedation, shortness of breath, nausea, vomiting, abdominal pain, and intoxicated feeling. Infrequently Observed All adverse events tabulated below are classified as infrequent. Central Nervous System: headache, shaky feeling, tingling, agitation, fainting, fatigue, heavy eyelids, high energy, hot spells, numbness, sluggishness, seizure.

Mental confusion, excitement or depression can also occur due to intolerance, particularly in elderly or debilitated patients, or due to overdosage of butalbital. Autonomic Nervous System: dry mouth, hyperhidrosis. Gastrointestinal: difficulty swallowing, heartburn, flatulence, constipation.

Cardiovascular: tachycardia. Musculoskeletal: leg pain, muscle fatigue. Genitourinary: diuresis.

Miscellaneous: pruritus, fever, earache, nasal congestion, tinnitus, euphoria, allergic reactions. Several cases of dermatological reactions, including toxic epidermal necrolysis and erythema multiforme, have been reported. The following adverse drug events may be borne in mind as a potential effect of the components of this product.

Potential effects of high dosage are listed in the OVERDOSAGE section. Acetaminophen: allergic reactions, rash, thrombocytopenia, agranulocytosis.

Drug Interactions The CNS effects of butalbital may be enhanced by monoamine oxidase (MAO) inhibitors. Butalbital and acetaminophen may enhance the effects of:other narcotic analgesics, alcohol, general anesthetics, tranquilizers such as chlordiazepoxide, sedative-hypnotics, or other CNS depressants, causing increased CNS depression.

Pregnancy Teratogenic Effects Pregnancy Category C Animal reproduction studies have not been conducted with this combination product. It is also not known whether butalbital and acetaminophen can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. This product should be given to a pregnant woman only when clearly needed.

Nonteratogenic Effects Withdrawal seizures were reported in a two-day-old male infant whose mother had taken a butalbital-containing drug during the last two months of pregnancy. Butalbital was found in the infant’s serum. The infant was given phenobarbital 5 mg/kg, which was tapered without further seizure or other withdrawal symptoms.

Pediatric Use Safety and effectiveness in pediatric patients below the age of 12 have not been established.

This product is contraindicated under the following conditions: Hypersensitivity or intolerance to any component of this product. Patients with porphyria.

Following an acute overdosage, toxicity may result from the barbiturate or the acetaminophen. Signs and Symptoms Toxicity from barbiturate poisoning includes drowsiness, confusion, and coma; respiratory depression; hypotension; and hypovolemic shock. In acetaminophen overdosage: dose-dependent, potentially fatal hepatic necrosis is the most serious adverse effect.

Renal tubular necroses, hypoglycemic coma and coagulation defects may also occur. Early symptoms following a potentially hepatotoxic overdose may include: nausea, vomiting, diaphoresis and general malaise. Clinical and laboratory evidence of hepatic toxicity may not be apparent until 48 to 72 hours post-ingestion.

Treatment A single or multiple drug overdose with butalbital and acetaminophen is a potentially lethal polydrug overdose, and consultation with a regional poison control center is recommended. Immediate treatment includes support of cardiorespiratory function and measures to reduce drug absorption. Oxygen, intravenous fluids, vasopressors, and other supportive measures should be employed as indicated.

Assisted or controlled ventilation should also be considered Gastric decontamination with activated charcoal should be administered just prior to N-acetylcysteine (NAC) to decrease systemic absorption if acetaminophen ingestion is known or suspected to have occurred within a few hours of presentation. Serum acetaminophen levels should be obtained immediately if the patient presents 4 hours or more after ingestion to assess potential risk of hepatotoxicity; acetaminophen levels drawn less than 4 hours post-ingestion may be misleading. To obtain the best possible outcome, NAC should be administered as soon as possible where impending or evolving liver injury is suspected.

Intravenous NAC may be administered when circumstances preclude oral administration. Vigorous supportive therapy is required in severe intoxication. Procedures to limit the continuing absorption of the drug must be readily performed since the hepatic injury is dose dependent and occurs early in the course of intoxication.