• Tonic-clonic (grand mal), partial, and febrile seizures in children.
• Preoperative sedative and in other situations in which sedation may be required.
• Hypnotic (short-term).

Contraindicated in:

• Hypersensitivity
• Comatose patients or those with pre-existing CNS depression
• Severe respiratory disease with dyspnea or obstruction
• Uncontrolled severe pain
• Known alcohol intolerance (elixir only)
• Lactation: Lactation.

Use Cautiously in:

• Hepatic impairment
• Severe renal impairment
• History of suicide attempt or drug abuse
• OB: Chronic use during pregnancy results in drug dependency in the infant; may result in coagulation defects and fetal malformation; acute use at term may result in respiratory depression in the newborn
• Geri: Appears on Beers list. Older adults have ↑ risk of physical dependence and risk of toxicity at lower doses. If possible, avoid use in older adults.

CV: IV: hypotension.

Derm: photosensitivity, rash, urticaria.

GI: constipation, diarrhea, nausea, vomiting.

Local: phlebitis at IV site.

MS: arthralgia, myalgia.

Neuro: hangover, delirium, depression, drowsiness, excitation, lethargy, neuralgia, vertigo.

Resp: respiratory depression.
IV: LARYNGOSPASM, bronchospasm.
Misc: (INCLUDING ANGIOEDEMA AND SERUM SICKNESS)HYPERSENSITIVITY REACTIONS , physical dependence, psychological dependence.

Drug-Drug:

• Additive CNS depression with other CNS depressants, including alcohol, antihistamines, opioid analgesics, and other sedative/hypnotics.
• May induce hepatic enzymes that metabolize other drugs, ↓ their effectiveness, including hormonal contraceptives, warfarin, chloramphenicol, cyclosporine, dacarbazine, corticosteroids, tricyclic antidepressants, felodipine, clonazepam, carbamazepine, verapamil, theophylline, metronidazole, and quinidine.
• May ↑ risk of hepatic toxicity of acetaminophen.
• MAO inhibitors, valproic acid, or divalproex may ↓ metabolism of phenobarbital, ↑ sedation.
• Rifampin may ↑ metabolism of and ↓ effects of phenobarbital.
• May ↑ risk of hematologic toxicity with cyclophosphamide.

Drug-Natural Products:

• Concomitant use of kava-kava, valerian, chamomile, or hops can ↑ CNS depression.
• St. John’s wort may ↓ effects.

(Generic available)

• Tablets: 15 mg; 16.2 mg; 30 mg; 32.4 mg; 60 mg; 64.8 mg; 97.2 mg; 100 mg;
• Elixir: 20 mg/5 mL;
• Lyophilized powder for injection: 100 mg/vial;
• Solution for injection: 65 mg/mL; 130 mg/mL;

Status Epilepticus

• IV (Adults and Children >1 mo): 15–18 mg/kg in a single or divided dose, maximum loading dose 20 mg/kg.
• IV (Neonates): 15–20 mg/kg in a single dose. If clinically indicated, 15 minutes after completion of the initial loading dose, a 2nd loading dose may be administered over the subsequent 15 minutes as 20 mg/kg for term infants or 10–20 mg/kg for preterm infants.

Maintenance Anticonvulsant

• IV, PO (Adults and Children >12 yr): 1–3 mg/kg/day as a single dose or 2 divided doses.
• IV, PO (Children >5 yr): 2–3 mg/kg/day in 1–2 divided doses.
• IV, PO (Children 5 yr): 3–5 mg/kg/day in 1–2 divided doses.

Sedation

• PO, IM (Adults): 30–120 mg/day in 2–3 divided doses. Preoperative sedation: 100–200 mg IM 1–1.5 hr before the procedure.
• PO (Children): 2 mg/kg 3 times daily. Preoperative sedation: 1–3 mg/kg PO/IM/IV 1–1.5 hr before the procedure.

Hypnotic

• PO, SC, IV, IM (Adults): 100–320 mg at bedtime.
• IV, IM, SC (Children): 3–5 mg/kg at bedtime.

Hyperbilirubinemia

• PO (Adults): 90–180 mg/day in 2–3 divided doses.
• PO (Children <12 yr): 3–8 mg/kg/day in 2–3 divided doses, doses up to 12 mg/kg/day have been used.

Luminal, Sezaby

• Produces all levels of CNS depression.
• Depresses the sensory cortex, decreases motor activity, and alters cerebellar function.
• Inhibits transmission in the nervous system and raises the seizure threshold.
• Capable of inducing (speeding up) enzymes in the liver that metabolize drugs, bilirubin, and other compounds.

• Anticonvulsant activity.
• Sedation.

Therapeutic Classification: anticonvulsants, sedative/hypnotics

Pharmacologic Classification: barbiturates

Absorption: Absorption is slow but relatively complete (70–90%).

Distribution: Unknown.

Metabolism/Excretion: 75% metabolized by the liver, 25% excreted unchanged by the kidneys.

Half-life: Neonates: 1.8–8.3 days; Infants: 0.8–5.5 days; Children: 1.5–3 days; Adults: 2–6 days.

Schedule IV (C-IV)

(sedation†)

†Full anticonvulsant effects occur after 2–3 wk of chronic dosing unless a loading dose has been used.

• Advise patient to take medication as directed. Take missed doses as soon as remembered if not almost time for next dose; do not double doses.
• Advise patients on prolonged therapy not to discontinue medication without consulting health care professional. Abrupt withdrawal may precipitate seizures or status epilepticus.
• Medication may cause daytime drowsiness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known. Do not resume driving until physician gives clearance based on control of seizure disorder.
• Caution patient to avoid taking alcohol or other CNS depressants, including opioids, concurrently with this medication.
• Advise patient to notify health care professional if signs and symptoms of angioedema, fever, sore throat, mouth sores, unusual bleeding or bruising, nosebleeds, or petechiae occur.
• Teach sleep hygiene techniques (dark room, quiet, bedtime ritual, limit daytime napping, avoid nicotine and caffeine).
• Advise females of reproductive potential using oral contraceptives to use an additional nonhormonal contraceptive during therapy and until next menstrual period. Instruct patient to notify health care professional immediately if pregnancy is planned or suspected or if breastfeeding. Use during third trimester of pregnancy may cause withdrawal symptoms in the neonate, including seizures and hyperirritability; symptoms of withdrawal may be delayed in the neonate up to 14 days after birth. Monitor infant for respiratory depression if used during labor. A registry is available for women exposed to phenobarbital during pregnancy: Pregnant women may enroll themselves into the North American Antiepileptic Drug Pregnancy Registry (1-888-233-2334 or www.aedpregnancyregistry.org).
• Pedi: Advise parents or caregivers that child may experience irritability, hyperactivity, and/or sleep disturbances, which may diminish in a few days to a few wk or may persist until drug is stopped. An alternative medication can be considered. Instruct parents to monitor for skin rash occurring 7–20 days after treatment begins and to contact a health care provider if rash occurs. Teach family about symptoms of toxicity (staggering, drowsiness, slurred speech).

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