Thiopental Sodium

Brand names Pentothal

Medication error High-alert medication (anesthetic and moderate sedation) that has an increased risk of potential causing significant patient harm if it is used in error.(1) Look-alike, sound-alike drug names. Confusion between thiopental and Nembutal occurred but did not result in patient harm.(2)

Contraindications Contraindications: Hypersensitivity to thiopental, barbiturates, or any component of the and warnings formulation.(3) Absence of suitable veins for IV administration; should not be administered by intra-arterial injection.(3) Variegate porphyria (South African) or acute intermittent porphyria.(3) Relative contraindications include severe cardiovascular disease, hypotension, or shock conditions in which the hypnotic effect may be prolonged or potentiated (e.g., excessive premedication, Addison disease, hepatic or renal dysfunction, myxedema, increased BUN, severe anemia, asthma/status asthmaticus, and myasthenia gravis). Warnings: May be habit forming.(3) Resuscitative, endotracheal intubation equipment, and oxygen should be readily available. Monitor oxygen saturation and keep oxygen available.(3)

Infusion-related Respiratory depression, apnea, laryngospasm, and hypotension may occur if administered cautions too rapidly.(3) High alkaline pH (10.6) may cause tissue necrosis upon extravasation.(3) (See Appendix E for management of intra-arterial injection.)

Dosage Anesthesia Induction: Doses have ranged from 4–8.6 mg/kg over 10–60 minutes.(3-7) Although some have suggested that the induction doses of thiopental should be larger (relative to weight) in children (5–8 mg/kg)(8) and lower in neonates (3–4 mg/kg),(9) others have found no difference in dosing based on age.(10,11) If clinically indicated, 0.1 mg/kg/sec may be given until the face mask is tolerated.(12) Although rapid injection can cause hypotension and decreased cardiac output, doses of 5 mg/kg have been given over 10 seconds when rapid induction was needed.(5) Maintenance: 1 mg/kg PRN(3) Elevated intracranial pressure Acute increases: 1.5–3.5 mg/kg, repeat PRN(3,4) Sustained elevations (medically induced coma) Neonates: A loading dose of 10–30 mg/kg(13-15) followed by 2–4 mg/kg/hr as a continuous infusion.(13,14) Two studies evaluated the effects of short-term(14,15) and prolonged coma with thiopental on outcomes in neonates with asphyxia and reported no improvement; however, a greater complication rate (i.e., hypotension) was noted.(14,15) Infants and children: A loading dose of 10–30 mg/kg.(13,16-18) Some investigators recommend administration of two loading doses: 20 mg/kg over 1 hour followed by 10 mg/kg over 6 hours.(13) The loading dose should be followed by a continuous infusion of 1–2 mg/kg/hr and should be titrated based on clinical response and/ or serum thiopental concentration (20–40 mg/L).(13,16,17) Procedural sedation (for procedures <15 minutes): Has been given rectally for this purpose(19); however, other barbiturates are more frequently used. (See the Pentobarbital monograph.)

 814 Thiopental Sodium

Dosage (cont.) Status epilepticus Loading: 10–30 mg/kg(20,21) Maintenance: Most clinicians begin at 5 mg/kg/hr and gradually increase by 1–2 mg/kg/hr for 6–8 hours until all electrical brain activity is suppressed.(21,26) Total doses of thiopental used to obtain and maintain burst suppression were 15–50 g over 48–120 hours and correlated with plasma thiopental levels of 25–40 mg/dL.(21)

Dosage adjustment Because the hypnotic effect may be prolonged in renal or hepatic disease, use cautiously in organ dysfunction in these patients.(3,24) Adjust dose in renal dysfunction.(24,25) If CrCl is <10 mL/min, give 75% of normal dose.(21) May need to reduce dosage in hepatic failure/cirrhosis but no specific recommendations.(25)

Maximum dosage Not established

Additives 4.9 mEq sodium/g of thiopental sodium(3,27)

Suitable diluents D2.5, D5W, NS, ½NS, D2.5NS, D2.5¼NS, D5¼NS, D5½NS, dextran 6% in D5W, and dextran 6% in NS(3,27) SW should not be used for preparing solutions <2% thiopental since the resulting hypotonic solutions will cause hemolysis.(27)

Maximum 50 mg/mL(3) concentration

Preparation and Parenteral products should be visually inspected for particulate matter and discoloration delivery before use. Refer to appropriate references(27) for more information on compatibility with other drugs and solutions; compatibility following Y-site delivery, and suggested storage and extended stability. Stability: 3 days at room temperature (20°C to 25°C) and 7 days when refrigerated (2°C to 8°C)(27)

IV push Over 20–30 seconds. Twenty infants, age 12 months, received 5 mg/kg over 10 seconds for rapid anesthesia induction(12) and 10 mg was given over 2 minutes to neonates with resistant seizures without adverse effects.(20)

Intermittent infusion 20–50 mg/mL given over 10–60 minutes with rate titrated according to blood pressure(13,14,28)

Continuous infusion 2–4 mg/mL in D5W or NS(3)

Other routes of IM administration is not recommended due to tissue necrosis.(3,27) administration

Comments Rare adverse effects: Renal failure may occur as a complication of barbiturate treat- ment. Monitor BUN and SCr.(29) Anticonvulsant hypersensitivity syndrome is an acute, life-threatening, idiosyncratic reac- tion that has been reported in patients receiving phenytoin, phenobarbital, carbamaze- pine, primidone, and lamotrigine.(29-31) Symptoms generally develop within 1–12 weeks following initiation and include a classic triad of fever, rash, and lymphadenopathy.(29-31) Peripheral blood leucocytosis and eosinophilia and internal organ involvement may also be noted. Immediate discontinuation of the suspected anticonvulsant is essential for good outcomes.(29-31) Cross-reactivity among the aromatic anticonvulsants has been noted; hence, these should not be used as alternative agents.(29-31)  815