Phenobarbital

Brand names: B-Donna, Belladonna Alkaloids with Phenobarbital, Belladonna Alkaloids with Phenobartbital, Donnatal, Donnatal Extentabs, Me-PB-Hyos, Phenobarbital with Belladonna Alkaloids, Phenobarbital, Hyoscyamine Sulfate, Atropine Sulfate and Scopolamine Hydrobromide, Phenohytro, Phenobarbital, PHENOBARBITAL

Warnings

BOXED WARNING: "MAY BE HABIT-FORMING." The label states "tolerance and psychological and physical dependence may occur with continued use," and that "abrupt cessation after prolonged use in a person who is dependent on the drug may result in withdrawal symptoms, including delirium, convulsions, and possibly death." Prescribing and dispensing should be "limited to the amount required for the interval until the next appointment." As a CNS depressant, the label warns that "the concomitant use of alcohol or other CNS depressants may produce additive CNS depressant effects" - a category that includes opioid analgesics, raising the risk of profound sedation and respiratory depression when combined. The label also warns that "barbiturates can cause fetal damage when administered to a pregnant woman."

Contraindications

CONTRAINDICATIONS Phenobarbital is contraindicated in patients who are hypersensitive to barbiturates. In such patients, severe hepatic damage can occur from ordinary doses and is usually associated with dermatitis and involvement of parenchymatous organs. A personal or familial history of acute intermittent porphyria represents one of the few absolute contraindications to the use of barbiturates. Phenobarbital is also contraindicated in patients with marked impairment of liver function, or respiratory disease in which dyspnea or obstruction is evident. It should not be administered to persons with known previous addiction to the sedative/hypnotic group, since ordinary doses may be ineffectual and may contribute to further addiction.

Overdose

OVERDOSAGE The signs and symptoms of barbiturate poisoning are referable especially to the central nervous system and the cardiovascular system. Moderate intoxication resembles alcoholic inebriation. In severe intoxication, the patient is comatose, the level of reflex activity conforming in a general way to the intensity of the central depression. The deep reflexes may persist for some time despite coexistent coma. The Babinski sign is often positive. The EEG may be of the “burst-suppression” type, with brief periods of electrical silence. The pupils may be constricted and react to light, but late in the course of barbiturate poisoning they may show hypoxic paralytic dilatation. Respiration is affected early. Breathing may be either slow or rapid and shallow; Cheyne-Stokes rhythm may be present. Respiratory minute volume is diminished, and hypoxia and respiratory acidosis may develop. The blood pressure falls, owing partly to depression of medullary vasomotor centers; partly to a direct action of the drug on the myocardium, sympathetic ganglia, and vascular smooth muscle; partly to hypoxia. The patient thus develops a typical shock syndrome, with a weak and rapid pulse, cold and clammy skin, and a rise in the hematocrit. Respiratory complications (atelectasis, pulmonary edema, and bronchopneumonia) and renal failure are much dreaded and not infrequent concomitant of severe barbiturate poisoning. There is usually hypothermia, sometimes with temperatures as low as 32°C. Treatment: General management should consist of symptomatic and supportive therapy, including gastric lavage, administration of intravenous fluids, and maintenance of blood pressure, body temperature and adequate respiratory exchange. Dialysis will increase the rate of removal of barbiturates from the body fluids. Antibiotics may be required to control pulmonary complications.

Drug interactions

Drug Interactions: Phenobarbital in combination with alcohol, tranquilizers, and other central nervous system depressants has additive depressant effects, and the patient should be so advised. Patients taking this drug should be warned not to exceed the dosage recommended by their physician. Toxic effects and fatalities have occurred following overdoses of phenobarbital alone and in combination with other central nervous system depressants. Caution should be exercised in prescribing unnecessarily large amounts of phenobarbital for patients who have a history of emotional disturbances or suicidal ideation or who have misused alcohol and other CNS drugs (see OVERDOSAGE ).

Uses

Indicated as a sedative, and "for the treatment of generalized and partial seizures," including generalized tonic-clonic (grand mal) and cortical focal seizures; also used for short-term sedation of anxiety and tension.

Dosage forms & strengths

Tablet Tablet, Film Coated, Extended Release TABLET POWDER LIQUID SOLUTION ELIXIR

ATROPINE SULFATE 0.0194 mg HYOSCYAMINE SULFATE 0.1037 mg SCOPOLAMINE HYDROBROMIDE 0.0065 mg PHENOBARBITAL 16.2 mg PHENOBARBITAL 100 mg PHENOBARBITAL 15 mg PHENOBARBITAL 30 mg PHENOBARBITAL 32.4 mg PHENOBARBITAL 48.6 mg / HYOSCYAMINE 0.3111 mg / ATROPINE SULFATE 0.0582 mg / SCOPOLAMINE HYDROBROMIDE 0.0195 mg PHENOBARBITAL 60 mg PHENOBARBITAL 64.8 mg PHENOBARBITAL 97.2 mg Phenobarbital 100 mg Phenobarbital 15 mg Phenobarbital 16.2 mg Hyoscyamine Sulfate 0.1037 mg Atropine Sulfate 0.0194 mg Scopolamine Hydrobromide 0.0065 mg Phenobarbital 30 mg Phenobarbital 32.4 mg Phenobarbital 48.6 mg HYOSCYAMINE SULFATE 0.3111 mg ATROPINE SULFATE 0.0582 mg SCOPOLAMINE HYDROBROMIDE 0.0195 mg Phenobarbital 60 mg Phenobarbital 64.8 mg Phenobarbital 97.2 mg PHENOBARBITAL 64.8 mg/1 PHENOBARBITAL 16.2 mg/1 PHENOBARBITAL 1 kg/kg PHENOBARBITAL 25 kg/25kg PHENOBARBITAL 100 mg/1 PHENOBARBITAL 60 mg/1 PHENOBARBITAL 32.4 mg/1 PHENOBARBITAL 97.2 mg/1 PHENOBARBITAL 30 mg/1 PHENOBARBITAL 15 mg/1 PHENOBARBITAL 20 mg/5mL PHENOBARBITAL 1 g/g

DOSAGE AND ADMINISTRATION Oral Sedative Dose, Adults - 30 to 120 mg daily in 2 or 3 divided doses. Children - 6 mg/kg of body weight daily in 3 divided doses. Oral Hypnotic Dose, Adults - 100 to 320 mg. Oral Anticonvulsant Dose, Adults - 50 to 100 mg 2 or 3 times daily. Children - 15 to 50 mg 2 or 3 times daily.

Ingredients

Inactive:

INACTIVE INGREDIENT Inactive ingredients include: colloidal silicon dioxide, lactose anhydrous, magnesium stearate, microcrystalline cellulose, sodium starch glycolate, and stearic acid.