Butabarbital Contraindications and Precautions
- abrupt discontinuation
- agranulocytosis
- barbiturate hypersensitivity
- breast-feeding
- ethanol intoxication
- hepatic encephalopathy
- pain
- porphyria
- alcoholism
- anticoagulant therapy
- asthma
- carbamazepine hypersensitivity
- cardiac disease
- children
- chronic obstructive pulmonary disease (COPD)
- CNS depression
- depression
- driving or operating machinery
- elderly
- exfoliative dermatitis
- hepatic disease
- hydantoin hypersensitivity
- hypotension
- infants
- labor
- mental status changes
- osteomalacia
- osteoporosis
- pregnancy
- pulmonary disease
- renal disease
- renal failure
- renal impairment
- respiratory depression
- seizure disorder
- seizures
- sleep apnea
- status asthmaticus
- status epilepticus
- substance abuse
- suicidal ideation
- tartrazine dye hypersensitivity
Butabarbital Contraindications / Precautions
Patients with tartrazine dye hypersensitivity who are taking butabarbital should be warned that the 30 mg and 50 mg tablets and the elixir product of Butisol Sodium® contain tartrazine dye (FD&C yellow No. 5). Tartrazine dye hypersensitivity occurs frequently in patients who are allergic to aspirin, although overall, the incidence of tartrazine dye hypersensitivity is low.
Avoid use of butabarbital in patients with a history of barbiturate hypersensitivity. Barbiturates can cause severe and potentially fatal reactions that are preceded by skin eruptions. Therapy should be prescribed only after critical benefit-to-risk appraisal in patients with a history of adverse hematologic (i.e., agranulocytosis), hypersensitivity, or other adverse reactions to barbiturate or other anticonvulsants. Hypersensitivity reactions to anticonvulsants may present as various organ system problems, including cardiac, liver, renal, and skin disorders. Skin reactions can precede potentially fatal hypersensitivity reactions; exfoliative dermatitis has resulted in fatalities. A history of hypersensitivity reactions should be obtained for a patient and the immediate family members. Hypersensitivity reactions have been reported in patients who previously experienced hydantoin hypersensitivity (e.g., phenytoin) or carbamazepine hypersensitivity. Estimates of cross-sensitivity vary, but may range from 30 - 80%. Phenytoin, carbamazepine, and phenobarbital are all metabolized to hydroxylated aromatic compounds via the cytochrome P450 hepatic oxidative enzymes; arene oxide intermediates are formed during metabolism and are thought to be responsible for cross-sensitivity among these anticonvulsants in susceptible individuals. Some individuals may have a reduced ability to detoxify the intermediate toxic metabolites (e.g., arene oxides) of these anticonvulsants, which may be genetically mediated. However, studies of familial reactions have also shown that allergies to one anticonvulsant may not translate to allergies to others. There is no way to predict with certainty which patients will exhibit cross-sensitivity.
Avoid the use of butabarbital in patients in acute or chronic pain, as the pain may be exacerbated. Barbiturates have no analgesic activity. Paradoxical reactions, such as agitation and hyperactivity may occur in patients with acute pain.
Butabarbital should be used with extreme caution in patients with mental status changes, major depression or suicidal ideation because the CNS-depressant effects of butabarbital can exacerbate these conditions.
Because butabarbital can cause dose-dependent respiratory depression, it should be used cautiously in patients with pulmonary disease states causing respiratory depression, dyspnea, severe pulmonary insufficiency or airway obstruction. Barbiturates should be avoided in patients with bronchopneumonia. Use with close supervision in patients with sleep apnea or chronic obstructive pulmonary disease (COPD). Avoid butabarbital use in patients with status asthmaticus or asthma.
Insomnia is no longer a generally accepted use of butabarbital. If it is used for insomnia, butabarbital should not be used for longer than 2 weeks due to the development of tolerance. Butabarbital should be prescribed with caution to patients with known substance abuse because of the potential for psychological and/or physical dependence to the drug. Avoid abrupt discontinuation of butabarbital after prolonged use to limit drug withdrawal and/or seizure onset. Sudden, abrupt discontinuation of butabarbital in epileptic patients may precipitate acute seizures, status epilepticus, or other seizure disorder.
Butabarbital may cause blurred vision, drowsiness, or dizziness, especially with initial use. Patients should use caution when driving or operating machinery until they are aware of the effects of the drug. Ethanol intoxication or concomitant use of other sedating drugs can magnify CNS depression and is best avoided. Avoid use of butabarbital in patients with alcoholism; seizure activity may be induced.
Butabarbital should be used with caution in the elderly or debilitated patient. The elderly are generally more sensitive to the sedative effects of the drug. The elderly are also more likely to have medical conditions aggravated by the use of this drug or to experience confusion or paradoxical CNS stimulation. Avoid the use of butabarbital as a hypnotic in the elderly; this is no longer a generally accepted use. According to US federal OBRA regulations, butabarbital is not to be used in a nursing home patient unless started before admission to the nursing home, or given as a single dose for a medical or dental procedure (see Dosage). In general, avoid the use of butabarbital in the elderly due to excess adverse events, such as confusion and instability.
Butabarbital is extensively metabolized in the liver. Those with hepatic disease may be at increased risk for developing drug toxicity and may require lower dosage and slower dosage titration; avoid butabarbital in patients with marked liver impairment. Because barbiturates may impair the ability of the liver to metabolize ammonia, barbiturates are best avoided in patients with hepatic encephalopathy. Note that barbiturates are hepatic enzyme inducers and patients should be monitored for altered drug levels and therapeutic effects as indicated (see Drug Interactions).
Butabarbital metabolites are excreted via the kidney and cautious use should be exercised in patients with severe renal impairment or renal failure. It appears no dosage alterations are required with renal impairment.
Butabarbital, like other barbiturates, should not be used in patients with acute intermittent porphyria or porphyria variegata. Butabarbital can exacerbate this disease. Barbiturates can stimulate the activity of enzymes like ALA synthetase, causing a buildup of porphyrin precursors and enhancing porphyrin synthesis.
Butabarbital may decrease the effect of oral coumarin (e.g., warfarin) anticoagulant therapy (see Drug Interactions) and necessitate upward dosage adjustment of the anticoagulant for optimal effect. Conversely, when the drug is discontinued, the dose of the anticoagulant may have to be decreased.
Use butabarbital with caution in patients with low bone density. There may be an increased risk of osteopenia/osteoporosis with long-term butabarbital therapy. Osteomalacia has been noted in patients using barbiturates who have end-stage renal disease.
Children are more likely than adults to react with paradoxical excitement to butabarbital. The safe use in children < 6 years of age has not been established.
Butabarbital is classified by the FDA as pregnancy risk category D. It should be used during pregnancy only if the benefits to the mother outweigh any potential risk to the fetus. There have been reports of physical abnormalities in infants correlating to exposure to barbiturates in utero. Additionally, a retrospective study revealed that in utero exposure to barbiturates was associated with intelligence deficits. Repeated use of butabarbital during the third trimester can also cause physical dependence in the neonate. There is no established use for butabarbital during labor or obstetrical delivery. However, if the mother used butabarbital late in pregnancy, newborns should be carefully observed for signs of ventilatory depression, particularly if the infant is premature. Females should be warned of the potential adverse effects on the fetus should pregnancy occur.
Butabarbital is excreted into breast milk and is not recommended for use in breast-feeding women. Because newborns have slower drug elimination mechanisms than adults, accumulation may occur, leading to toxic effects such as somnolence, irritability and poor feeding.Butabarbital should be used with caution in cases of hypotension, pulmonary disease, or cardiac disease because of possible adverse hemodynamic effects. In cases where an overdose of a barbiturate has occurred, symptoms may include: confusion, hypotension, incoherent speech, nystagmus, and tachycardia.
[ Last revised: 12/5/2003 12:39:00 PM ]
References
. Reinisch JM, Sanders SA, Mortensen EL et al. In utero exposure to phenobarbital and intelligence deficits in adult men. JAMA 1995;274:1518 - 25.
. Canaday BR. Anticonvulsant cross-sensitivity. Am J Health-Syst Pharm 1997;54:2616 - 7.
. Holmes LB, Harvey EA, Coull BA, et al. The teratogenecity of anticonvulsant drugs. N Engl J Med 2001;344:1132 - 8.
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