Parenteral Manual


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Alternate Name(s): 
Barbiturate- sedative, anticonvulsant
Original Date: 
August 2005
Revised Date: 
June 2016
  • Long acting barbiturate used as a sedative and hypnotic
  • Anticonvulsant for treatment of grand mal, partial and febrile seizures
Reconstitution and Stability: 
  • Available as a 30 mg/mL and 120 mg/mL  injection solution
  • Stable at room temperature, protect from light 
  • Watch for precipitation when diluting phenobarb or mixing with acidic solutions and additives

- Solutions Compatible: dextrose solutions up to D10W, NS, ringer's solution, ringer's lactate

- Additive/Above Cassette Compatible: caffeine, heparin

- Y-site Compatible: dexamethasone, dopamine, fentanyl, furosemide, indomethacin, KCl, sodium bicarbonate, amino acids and dextrose (AA/dextrose must not contain ranitidine)

- Incompatible: acidic drugs, amphotericin B, atracurium, chlorpromazine, clindamycin, dimenhydrinate, diphenhydramine, droperidol, fat emulsion (lipids), hydralazine, hydrocortisone sodium succinate, hydroxyzine, insulin, isoproterenol, meperidine, midazolam, norepinephrine, pancuronium, penicillin, prochlorperazine, ranitidine, vancomycin


(For approved routes of administration by nursing personnel, refer to Policy for the Administration of Intravenous Medications.)


Yes, use only if IV unavailable- absorption unreliable

Up to 20 mg/kg has been given by this method

IV Direct NO
IV Intermittent Infusion YES
Usual dilution: 5 mg/mL
Infusion time: over greater than or equal to 20 minutes.  Do not exceed 1 mg/kg/minute to a max of 30 mg/minute
IV Continuous Infusion NO

(For neonatal dosages, refer to Neonatal IV Drug Manual.)

- Anticonvulsant maintenance dose: 

  • Infant: 5-6 mg/kg/day IV in 1-2 divided doses
  • 1-5 yrs: 6-8 mg/kg/day IV in 1-2 divided doses
  • 5-12 years: 4-6 mg/kg/day IV in 1-2 divided doses
  • >12 and adult: 1-3 mg/kg/day in 1-2 divided doses

- Status Epilepticus:

  • 10-20 mg/kg/dose IV x 1 (Maximum: 1000 mg/dose)
  • May repeat with 5-10 mg/kg/dose Q 15-30 minutes PRN
  • Maximum total dose 30 mg/kg

- Hypnotic:  3-5 mg/kg IV/IM at bedtime

- Preoperative sedation:  1-3 mg/kg IV/IM 1-1.5 hours before procedure

- Status Epilepticus:

  • Loading dose of 10-20 mg/kg IV; repeat if necessary at 20 min intervals
  • Maximum total dose: 1-2 g

- Hypnotic: 100-325 mg IV/IM at bedtime

- Preoperative sedation:  100-200 mg IM 1-1.5 hours before procedure

Potential hazards of parenteral administration: 
  • Thrombophlebitis, pain at injection site, injury to nerves
  • Too rapid IV administration can cause respiratory depression, bronchospasm, hypotension, laryngospasm, coughing; therefore IV rate must NOT exceed 1 mg/kg/minute (or 30 mg/minute in infants & children, and 60 mg/minute for adults >60 kg)
  • Extravasation can cause tissue necrosis
  • Paradoxical hyperactivity in children
  • When used with phenytoin IV should monitor both levels
  • Monitor respiratory rate, HR, BP, CNS status, seizure activity, liver enzymes, renal function, CBC with differential, serum concentrations
  • Caution with IV administration to patients with hypertension, hypotension or pulmonary or cardiovascular disease.
  • Many drug interactions: consult an appropriate reference or pharmacy

Therapeutic Drug Monitoring:

  • Therapeutic serum concentration: 65-170 micromol/L
  • Usual sampling time: pre dose (0-60 minutes before next dose)
  • When to order levels: 
    - Post load - one hour post IV load
    - Steady state level 4 days after dosing change
    - Continued seizures or suspected toxicity (take level at time of symptoms)
  • Without a loading dose, it may take 1-3 weeks to reach adequate serum concentration

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