Thiopental Sodium

Registered South African indications:

• Induction of anaesthesia
• Adjunct for control of seizure disorders
• Preanaesthetic sedation

Contraindications

• Hypersensitivity to the active ingredient or any of its excipients
• Respiratory obstruction
• Acute asthma
• Severe shock
• Myotonic dystrophy 
• Porphyria
• Severe cardiovascular disease
• Severe respiratory depression
• Severe hypertension

Cautions

• Pregnancy
• Breastfeeding
• Renal impairment 
• Severe  hepatic impairment 
• Elderly 
• Hypovolaemia
• Severe haemorrhage
• Burns
• Myasthenia gravis
• Adrenocortical insufficiency
• Cachexia
• Raised intracranial pressure
• Raised blood urea
• Severe anaemia
• Hyperkalaemia
• Toxaemia
• Thyrotoxicosis
• Myxoedema
• Diabetes mellitus
• Substance abuse
• Sodium controlled diet

Forms avail. in SA and covered in this monograph: inj

Preanaesthetic sedation

• Rectal (inj): 30mg/kg, as a single dose

Induction of anaesthesia

• IV: 3-5mg/kg, titrated to response

Hypnosis during balanced anaesthesia

• IV: 25-100mg, repeated as needed; Max: 1g/dose (to avoid prolonged recovery)

Convulsive states

• IV: 50-125mg, as a single dose; Titrate by up to 250mg over 10min, as needed

Increased intracranial pressure

• IV: 1.5-3.0mg/kg/dose; Titrate to response

General anaesthesia in status epilepticus

• IV: Loading dose: 4mg/kg; Titrate by 50mg boluses at intervals of 2-3min; Maintenance (started 30min after loading dose): 1-5mg/kg/hr, as an infusion; Treatment duration: continue for at least 24hrs after seizure activity has ceased

Seek specialist neuroanaesthetic or neurointensivist advice when treating these patients

Wean infusion slowly: Titrate down by 1mg/kg at intervals of 12hrs

See additional prescribing points

Paed. forms avail. in SA and covered in this monograph: inj

Induction of anaesthesia

• IV: 2-5mg/kg; Titrated to response

Hypnosis during balanced anaesthesia

• IV: 1mg/kg, Repeated as needed

Refractory status epilepticus

• IV: 1-5mg/kg; Titrate to response

Increased intracranial pressure

• IV: 1-2mg/kg; Titrate to response

See additional prescribing points

Pregnancy

• Caution
• It has been shown that thiopental can be used without adverse effects during pregnancy. However, when considering use of thiopental the expected benefits should outweigh any potential risks

Breastfeeding

• Caution; not recommended
• Thiopental readily crosses the placental barrier and also appears in breast milk. Animal reproduction studies have not been conducted with thiopental. Therefore, breastfeeding should be temporarily suspended (for at least 12hrs) or breast milk expressed before the induction of anaesthesia

Renal Impairment

• Caution: no dose adjustment recommended

Hepatic Impairment

• Mild to moderate (Child-Pugh Class A and B): No dose adjustment recommended
• Severe (Child-Pugh Class C): Caution; dose adjustment recommended
  Use with high caution
  Reduce dose by 25% in patients with transaminases (ALT and AST) ≥two-times above the reference range

Elderly

• Caution; no dose adjustment recommended
  Avoid use as induction anaesthetic agent in elderly due to high risk of hypotension, renal impairment and respiratory distress

Porphyria Information

• Porphyrinogenic (P)

Drugs in Sport

• Permitted - No warnings

Central Nervous System Disorders

• Cerebral impairment
• Shivers
• Headache
• Dizziness
• Drowsiness
• Confusion
• Amnesia
• Malaise
• Fatigue
• Delirium 

Cardiovascular Disorders

• Hypotension
• Myocardial depression
• Arrhythmias

Respiratory Disorders

• Laryngeal spasm
• Coughing
• Sneezing
• Bronchospasm
• Respiratory depression

Gastrointestinal Disorders

• Vomiting

Endocrine and Metabolic Disorders

• Anorexia
• Hypokalaemia
• Hyperkalamia
• Hypothermia 

Skin and Subcutaneous Tissue Disorders

• Allergic skin reactions

Immune, Blood and Lymphatic System Disorders

• Hypersensitivity reactions

• Sulphafurazole
• Aspirin
• Calcium channel blockers
• Beta blockers
• Angiotensin-converting enzyme blockers
• Angiotensin receptor blockers
• Methyldopa
• Alpha blockers
• Analgaesics
• Isoniazid
• Sulphonamides
• Vancomycin
• Tricyclic antidepressants
• Monoamine oxidase inhibitors
• Antipsychotics
• Cyclizine
• Benzodiazepines
• Diazoxide
• Diuretics
• Metaclopramide
• Droperidol
• Nitrates
• Probenicid
• St John's wart
• Moxonidine
• Central nervous system depressants
• Vasodilator antihypertensives

None routine

Administrative

• Reconstitute 500mg with 10-20ml diluent (to make a 5% or 2.5% solution respectively)
• 0.9% sodium chloride or 5% dextrose can be used as diluent

Extravasation
Extravasation causes local tissue necrosis and severe pain. This can be relieved by application of an ice pack and local injection of hydrocortisone. The 5% solution is hypertonic and may cause pain on injection and thrombophlebitis.

Accidental intra-arterial injection
Accidental intra-arterial injection of thiopental sodium causes severe arterial spasm and an intense burning pain around the injection site. In the case of accidental intra-arterial injection of thiopental the needle should be left in-situ so that an injection of an antispasmodic, such as papaverine or prilocaine hydrochloride may be given. Anticoagulant therapy may also be started to reduce the risk of thrombosis.

Thiopental binds to the gamma-aminobutyric acid (GABA) receptor. This increases the duration of time the chloride ion pore is open, resulting in a prolonged post-synaptic inhibitory effect of GABA. Thiopental acts throughout the central nervous system but with particular effect in the mesencephalic reticular activating system.

Injection (per 20ml) 0.5g

• Thiopentone Sodium Fresenius (Fresenius)