Thiopental Sodium intravenous injection is indicated for:

• Use as a sole anesthetic agent for short procedures (up to 15 minutes).
• Induction of anesthesia before administering other anesthetic agents.
• As an adjunct to regional anesthesia.
• To provide hypnosis during balanced anesthesia along with agents for analgesia or muscle relaxation.
• Control of convulsive conditions occurring during or after inhalational or local anesthesia, or due to other causes.
• Management of neurosurgical patients with elevated intracranial pressure, provided adequate ventilation is maintained.
• Use in psychiatric conditions for procedures such as narcoanalysis and narcosynthesis.

Thiopental 500 mg Injection: Each pack contains one vial of 500 mg Thiopental Sodium (a sterile mixture of Thiopental Sodium and anhydrous Sodium Carbonate as a buffer) along with one 10 mL ampoule of water for injection.

Thiopental 1 g Injection: Each pack contains one vial of 1 g Thiopental Sodium (a sterile mixture of Thiopental Sodium and anhydrous Sodium Carbonate as a buffer) along with two 10 mL ampoules of water for injection.

Thiopental is a barbiturate used primarily for the induction of anesthesia prior to other general anesthetics and for short diagnostic, surgical, or therapeutic procedures with minimal pain. It is an ultra–short-acting central nervous system depressant that produces hypnosis and anesthesia but does not provide analgesia. Following intravenous administration, it induces hypnosis within 30–40 seconds. Recovery after a single small dose is rapid, although mild drowsiness and retrograde amnesia may occur. With repeated doses, thiopental accumulates in fatty tissues, where concentrations may reach 6 to 12 times higher than in plasma, resulting in prolonged anesthetic effects due to slow release.

Thiopental acts by binding to a specific site on the GABA receptor associated with chloride ion channels, prolonging their opening. This enhances the inhibitory effect of GABA in the brain, particularly in the thalamus, leading to sedation and anesthesia.

Thiopental Injection is administered intravenously normally as a 2.5% w/v solution. On occasions it may be administered as a 5% w/v solution (500 mg in 10 ml). The intravenous injection preparation should be used after reconstitution of the sterile powder with Water for Injections, usually to produce a 2.5% w/v solution.

Premedication: Premedication usually consists of atropine or scopolamine to suppress vagal reflexes and inhibit secretions. In addition, a barbiturate or an opiate is often given. Ideally, the peak effect of these medications should be reached shortly before the time of induction.

Test dose: It is advisable to inject a small "test" dose of 25 mg to 75 mg of Thiopental Sodium for Injection to assess tolerance or unusual sensitivity to Thiopental Sodium for Injection, and pausing to observe patient reaction for at least 60 seconds. If unexpectedly deep anesthesia develops or if respiratory depression occurs, consider these possibilities: (1) the patient may be unusually sensitive to Thiopental Sodium for Injection, (2) the solution may be more concentrated than had been assumed, or (3) the patient may have received too much.

Use in anaesthesia: Normal dosage for the induction of anesthesia is 100 mg to 150 mg injected over 10 to 15 seconds. If necessary, a repeat dose of 100 mg to 150 mg may be given after one minute. No fixed dosage recommendations for the intravenous injection can be given, since the dosage will need to be carefully adjusted according to the patient's response. Factors such as age, sex, and weight of the patient should be taken into consideration. Thiopental Sodium reaches effective concentrations in the brain within 30 seconds and anesthesia is normally produced within one minute of an intravenous dose.

• Adult: 100 mg to 150 mg intravenously over 10 to 15 seconds, normally as a 2.5% w/v solution. A repeat dose of 100 mg to 150 mg may be given after one minute. The intravenous injection should be given slowly and the amount given titrated against the patient's response to minimize the risk of respiratory depression or the possibility of over dosage. The average dose for an adult of 70 kg is roughly 200 mg to 300 mg (8 mls to 12 mls of a 2.5% w/v solution) with a maximum of 500 mg.
• Children: 2 mg/kg to 7 mg/kg bodyweight, intravenously over 10 to 15 seconds, normally as a 2.5% w/v solution. A repeat dose of 2 mg/kg to 7 mg/kg may be given after one minute. The dose is 2 mg/kg to 7 mg/kg based on the patient's response. The dose for children should not exceed 7 mg/kg.
• Elderly: Smaller adult doses are advisable.

Use in convulsive states: 75 mg to 125 mg (3 mls to 5 mls of a 2.5% w/v solution) should be given as soon as possible after the convulsion begins. Further doses may be required to control convulsion following the use of a local anesthetic. Other regimens, such as the use of intravenous or rectal diazepam, may be used to control convulsive states.

Patients taking alcohol or other central nervous system (CNS) depressants may experience increased difficulty in achieving anesthesia. Thiopental exhibits additive effects when used with other CNS depressants such as sedatives, hypnotics, nitrous oxide, or alcohol. Concomitant use with phenothiazine antipsychotics may increase hypotension and excitatory responses, while other antipsychotics may enhance its hypnotic effects. The required dose of thiopental sodium may be reduced when administered with drugs such as metoclopramide, sulfisoxazole, aspirin, meprobamate, probenecid, and other highly protein-bound medications.

Absolute Contraindications:

• Lack of suitable veins for intravenous administration
• Hypersensitivity to barbiturates
• Variegate porphyria or acute intermittent porphyria
• Status asthmaticus

Relative Contraindications:

• Severe cardiovascular disease
• Hypotension or shock
• Conditions where the hypnotic effect may be prolonged or enhanced, such as excessive premedication, Addison’s disease, liver or kidney dysfunction, myxedema, elevated blood urea, severe anemia, asthma, or myasthenia gravis

Hypersensitivity reactions have been reported. Other adverse effects include respiratory depression, myocardial depression, cardiac arrhythmias, prolonged drowsiness and delayed recovery, hypotension, tachycardia, sneezing, coughing, bronchospasm, laryngospasm, and shivering. Severe allergic reactions such as anaphylaxis may occur, presenting with symptoms like urticaria, bronchospasm, vasodilation, and edema.

Pregnancy Category C. Adequate studies in animals and pregnant women are not available. It is not known whether thiopental can harm the fetus or affect reproductive capacity. It should be used during pregnancy only if clearly necessary. Thiopental crosses the placenta and may appear in small amounts in breast milk after high doses.

Thiopental should only be administered by trained personnel experienced in anesthesia. Facilities for respiratory and cardiovascular support must be readily available.

Use with caution in patients with hypotension or in conditions where prolonged sedation may occur, such as liver or kidney disease. The drug may be habit-forming. Airway patency must be maintained at all times, and resuscitation equipment, oxygen, and intubation facilities should be immediately accessible. Avoid accidental extravasation or intra-arterial injection.

Overdose may result from rapid or repeated administration. Rapid injection can cause a significant drop in blood pressure, even leading to shock. Respiratory complications such as apnea, laryngospasm, coughing, and breathing difficulties may occur. In suspected overdose, administration should be stopped immediately.

General intravenous anesthetic

Store at controlled room temperature (15°C to 30°C). Prepare solutions freshly and use immediately. Discard any unused portion.