Adult Dosing
Status epilepticus
- 15-18 mg/kg IV in a single or divided dose, Total max dose of 600 mg/24 Hours
Maintenance anticonvulsant
- 1-3 mg/kg/day IV as a single dose or divided bid
Sedation
- 30-120 mg/day IM divided bid-tid
- Preoperative sedation: 100–200 mg IM 1-1.5 hrs before the procedure
Pediatric Dosing
Status epilepticus
Neonates
- 10-20 mg/kg IV in a single or divided dose, over 1-15 min
Maintenance anticonvulsant
Child 5-12 yrs
- 4-6 mg/kg IV divided qd-bid
Child 1-5 yrs
- 6-8 mg/kg IV divided qd-bid
Infants
- 5-6 mg/kg IV divided qd-bid
Neonates
- 3-4 mg/kg IV divided qd-bid; may increase up to 5 mg/kg/day by 2nd week of therapy
Renal Dose Adjustment (Based on CrCl)
- Renal impairment
- >50 mL/min: Give q8-12 hrs
- 10-50 mL/min: Give q8-12 hrs
- <10 mL/min: Give q12-16 hrs
Hepatic Dose Adjustment
- Hepatic impairment
- Mild-moderate impairment: Dose reduction recommended; dose adjustments not defined
- Severe impairment: Contraindicated
- Tolerance and psychological and physical dependence may occur with continued use of therapy. Phenobarbital may be habit forming
- Increased doses or decreased dose interval may require in patients who have psychologic dependence
- Do not withdraw therapy abruptly which may result in withdrawal symptoms, including delirium, convulsions, and possibly death
- Cautiously administer therapy in patients with acute or chronic pain as paradoxical excitement could be induced or important symptoms could be masked
- Therapy has teratogenic effects when administered to a pregnant woman. Barbiturates readily cross the placental barrier and are distributed throughout fetal tissues. Pregnant women should be apprised of the potential hazard to the fetus while taking this drug
- In children taking phenobarbital for complicated febrile seizures cognitive deficits may occur
- The concomitant use of alcohol or other CNS depressants may produce additive CNS depressant effects
- Possible respiratory depression, apnea, laryngospasm, hypertension, or vasodilation and hypotension, particularly if phenobarbital is administered IV too rapidly; Administer slowly; personnel and equipment should be readily available for administration of artificial respiration
- Therapy may cause exfoliative dermatitis and hypersensitivity reactions particularly in patients with a history of asthma, urticaria, or angioedema. Suspend phenobarbital whenever dermatologic reactions occur
- Spasm and severe pain along the affected artery, resulting in local reactions varying in severity from transient pain to gangrene may occur due to inadvertent intra-arterial administration. Suspend therapy immediately and institute appropriate therapy if the patient complains of pain or if signs of inadvertent intra-arterial injection
- Cautiously administer in depressed patients, potential for suicidal tendencies. Use smaller doses in such patients
- Use parenterally with extreme caution in debilitated patients or patients with severe hepatic impairment, pulmonary or cardiac disease, status asthmaticus, uremia, or shock
Cautions: Use cautiously in
- Renal impairment
- Hepatic impairment
- History of drug abuse
- Elderly patients
- Pediatric patients
- Respiratory depression
- Depression or history of depression
Pregnancy Category:D
Breastfeeding: In infants who were exposed in utero, phenobarbital in breastmilk apparently can decrease withdrawal symptoms but it can also cause drowsiness in some infants, especially when used with other sedating drugs. This information is based upon LactMed database (available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 2 September 2011). According to manufacturer's data, as small amounts of barbiturates are excreted in the milk, caution should be exercised when phenobarbital is administered to a nursing woman.
