phenobarbital

Drug Name

Generic Name : phenobarbital ,phenobarbital sodium

Brand Name:
Oral preparations: Bellatal, Solfoton
Parenteral: Luminal Sodium

Classification: Barbiturate (long acting), Sedative, Hypnotic, Antiepileptic

Pregnancy Category D
Controlled Substance C-IV 

Dosage & Route

Available forms : Tablets—15, 16, 16.2, 30, 60, 90, 100 mg; capsules—16 mg; elixir—15 mg/5 mL, 20 mg/5 mL; injection—30, 60, 65, 130 mg/mL

ADULTS

Oral

  • Sedation: 30–120 mg/day in two to three divided doses. No more than 400 mg per 24 hr.
  • Hypnotic: 100–200 mg at bedtime.
  • Antiepileptic: 60–100 mg/day.

IM or IV

  • Sedation: 30–120 mg/day IM or IV in two to three divided doses.
  • Preoperative sedation: 100–200 mg IM, 60–90 min before surgery.
  • Hypnotic: 100–320 mg IM or IV.
  • Acute seizures: 200–320 mg IM or IV repeated in 6 hr if needed.
PEDIATRIC PATIENTS

Oral

  • Sedation: 2 mg/kg/dose PO tid. 8–32 mg/dose.
  • Hypnotic: Determine dosage using age and weight charts.
  • Antiepileptic: 3–6 mg/kg/day.

IM or IV

  • Preoperative sedation: 1–3 mg/kg IM or IV 60–90 min before surgery.
  • Antiepileptic: 4–6 mg/kg/day for 7–10 days to a blood level of 10–15 mcg/mL or 10–15 mg/kg/day IV or IM.
  • Status epilepticus: 15–20 mg/kg IV over 10–15 min.
GERIATRIC PATIENTS OR PATIENTS WITH DEBILITATING DISEASE OR RENAL OR HEPATIC IMPAIRMENT
  • Reduce dosage and monitor closely—may produce excitement, depression, confusion.
Therapeutic actions
  • Phenobarbitone is a short-acting barbiturate. It depresses the sensory cortex, reduces motor activity, changes cerebellar function, and produces drowsiness, sedation and hypnosis. Its anticonvulsant property is exhibited at high doses.
Indications
  • Oral or parenteral: Sedative
  • Oral or parenteral: Hypnotic, treatment of insomnia for up to 2 wk
  • Oral: Long-term treatment of generalized tonic-clonic and cortical focal seizures
  • Oral: Emergency control of certain acute seizures (eg, those associated with status epilepticus, eclampsia, meningitis, tetanus, and toxic reactions to strychnine or local anesthetics)
  • Parenteral: Preanesthetic
  • Parenteral: Treatment of generalized tonic-clonic and cortical focal seizures
  • Parenteral: Emergency control of acute seizures (tetanus, eclampsia, epilepticus)
Adverse effects
  • Bradycardia, hypotension, syncope; drowsiness, lethargy, CNS excitation or depression, impaired judgment, hangover effect, confusion, somnolence, agitation, hyperkinesia, ataxia, nervousness, headache, insomnia, nightmares, hallucinations, anxiety, dizziness; rash, exfoliative dermatitis; nausea, vomiting, constipation; agranulocytosis, thrombocytopenia, megaloblastic anaemia; pain at inj site, thrombophlebitis (IV); oliguria: laryngospasm, respiratory depression, apnoea (especially with rapid IV admin), hypoventilation.
  • Potentially Fatal: Stevens-Johnson syndrome.
Contraindications
  • Severe renal and hepatic disorders. Severe respiratory depression, dyspnea or airway obstruction; porphyria. Pregnancy.
Nursing considerations
Assessment
  • History: Hypersensitivity to barbiturates, manifest or latent porphyria; marked liver impairment; nephritis; severe respiratory distress; previous addiction to sedative-hypnotic drugs; pregnancy; acute or chronic pain; seizure disorders; lactation, fever; hyperthyroidism; diabetes mellitus; severe anemia; cardiac disease; shock; uremia; impaired liver or renal function; debilitation
  • Physical: Weight; T; skin color, lesions; orientation, affect, reflexes; P, BP, orthostatic BP; R, adventitious sounds; bowel sounds, normal output, liver evaluation; LFTs, renal function tests, blood and urine glucose, BUN
Interventions
  • Monitor patient responses, blood levels (as appropriate) if any interacting drugs listed above are given with phenobarbital; suggest alternative means of contraception to women using hormonal contraceptives.
  • WARNING: Do not give intra-arterially; may produce arteriospasm, thrombosis, gangrene.
  • Administer IV doses slowly.
  • Administer IM doses deep in a large muscle mass (gluteus maximus, vastus lateralis) or other areas where there is little risk of encountering a nerve trunk or major artery.
  • WARNING: Monitor injection sites carefully for irritation, extravasation (IV use). Solutions are alkaline and very irritating to the tissues.
  • Monitor P, BP, respiration carefully during IV administration.
  • Arrange for periodic lab tests of hematopoietic, renal, and hepatic systems during long-term therapy.
  • WARNING: Taper dosage gradually after repeated use, especially in patients with epilepsy. When changing from one antiepileptic drug to another, taper dosage of the drug being discontinued while increasing the dosage of the replacement drug.
Teaching points
  • This drug will make you drowsy and less anxious; do not try to get up after you have received this drug (request assistance to sit up or move around).
  • Take this drug exactly as prescribed; this drug is habit forming; its effectiveness in facilitating sleep disappears after a short time.
  • Do not take this drug longer than 2 weeks (for insomnia), and do not increase the dosage without consulting your health care provider.
  • Do not reduce the dosage or discontinue this drug (when used for epilepsy); abrupt discontinuation could result in a serious increase in seizures.
  • Wear a medical alert tag so that emergency medical personnel will know you have epilepsy and are taking this medication.
  • Avoid pregnancy while taking this drug; use a means of contraception other than hormonal contraceptives.
  • You may experience these side effects: Drowsiness, dizziness, hangover, impaired thinking (may lessen after a few days; avoid driving or engaging in dangerous activities); GI upset (take drug with food); dreams, nightmares, difficulty concentrating, fatigue, nervousness (reversible).
  • Report severe dizziness, weakness, drowsiness that persists, rash or skin lesions, fever, sore throat, mouth sores, easy bruising or bleeding, nosebleed, petechiae, pregnancy.