| Various sections have been changed.
Words in bold have been added to the previous document.
Section 1
Name changed to: Thiopental Sodium 500mg Powder for Solution for Injection
Section 2
All text changed to: Each vial contains 500mg Thiopental Sodium
For a full list of excipients see section 6.1
Section 4.2
Thiopental Injection BP is changed to: Thiopental Sodium 500mg Injection
Section 4.3
...Thiopental sodium is contra-indicated in...
The word "contra-indicated" appears 3 times in this section. It has been changed from "contraindicated" in the previous version of this document.
Section 4.4
All text in previous version of document is removed and replaced with: Thiopental sodium causes respiratory depression and a reduction in cardiac output and may precipitate acute circulatory failure in patients with cardiovascular disease, particularly constrictive pericarditis.
When particular caution is required
Special care is needed in administering thiopental sodium to patients with the following conditions:- hypovolaemia, severe haemorrhage, burns, cardiovascular disease, status asthmaticus, myasthenia gravis, adrenocortical insufficiency (even when controlled by cortisone), cachexia, raised intracranial pressure and raised blood urea.
Dose reduction required
Reduced doses are recommended in shock, dehydration, severe anaemia, hyperkalaemia, toxaemia, metabolic disorders e.g. thyrotoxicosis, myxoedema and diabetes.
Use in hepatic and renal disease
Thiopental sodium is metabolised primarily by the liver so doses should be reduced in patients with hepatic impairment. Barbiturate anaesthetics should be used with caution in severe renal disease. Reduced doses are also indicated in the elderly and in patients who have been premedicated with narcotic analgesics.
Use with other medications (see also section 4.5) and in underlying disease
Thiopental sodium has been shown to interact with sulphafurazole. Reduced initial doses may be required to achieve adequate anaesthesia, but repeat doses may also be necessary to maintain anaesthesia.
Patients taking long-term medications such as aspirin, oral anticoagulants, oestrogens, MAOIs and lithium may need to adjust the dose or stop therapy prior to elective surgery. Patients with diabetes or hypertension may need to adjust their therapy before anaesthesia.
Increased doses
Increased doses may be necessary in patients who have either a habituation or addiction to alcohol or drugs of abuse. Under these circumstances it is recommended that supplementary analgesic agents are used.
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% w/v 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.
Section 4.5
All text in this section has been removed/altered and replaced with: Thiopental sodium has been shown to interact with sulphafurazole (see also section 4.4).
It should be noted that thiopental will interact with beta-blockers and calcium antagonists causing a fall in blood pressure.
ACE inhibitors: enhanced hypotensive effect when general anaesthetics given with ACE inhibitors.
Adrenergic neurone blockers: Enhanced hypotensive effect when general anaesthetics given with adrenergic neurone blockers.
Alpha-blockers: Enhanced hypotensive effect when general anaesthetics given with alpha-blockers.
Analgesics: Pretreatment with aspirin has been shown to potentiate thiopental sodium anaesthesia. Opioid analgesics can potentiate the respiratory depressant effect of barbiturate anaesthetics and the dose of anaesthetic may need to be reduced. The analgesic effect of pethidine can be reduced by thiopental sodium.
Angiotensin-II receptor antagonists: Enhanced hypotensive effect when general anaesthetics given with angiotensin-II receptor antagonists.
Antibacterials: General anaesthetics possibly potentiate hepatotoxicity of isoniazid; effects of thiopental sodium enhanced by sulphonamides; hypersensitivity-like reactions can occur when general anaesthetics given with intravenous vancomycin.
Antidepressants: Increased risk of arrhythmias and hypotension when general anaesthetics given with tricyclic antidepressants. Hypotension and hypertension has been seen with MAOIs.
Antipsychotics: Patients being treated with phenothiazine antipsychotics may experience increased hypotension. Some phenothiazines, especially promethazine, may also increase the incidence of excitatory phenomena produced by barbiturate anaesthetics; cyclizine may possibly have a similar effect. The sedative properties may be also potentiated by thiopental sodium.
Benzodiazepines: Midazolam potentiates the anaesthetic effects of thiopental sodium.
Diazoxide: Enhanced hypotensive effect when general anaesthetics given with diazoxide.
Diuretics: Enhanced hypotensive effect when general anaesthetics given with diuretics.
Gastrointestinal drugs: Metoclopramide and droperidol reduce the dose of thiopental sodium required to induce anaesthesia.
Methyldopa: enhanced hypotensive effect when general anaesthetics given with methyldopa.
Moxonidine: Enhanced hypotensive effect when general anaesthetics given with moxonidine
Nitrates: Enhanced hypotensive effect when general anaesthetics given with nitrates.
Probenecid: Pretreatment with probenecid has been shown to potentiate thiopental sodium anaesthesia.
Vasodilator antihypertensives: Enhanced hypotensive effect when general anaesthetics given with hydralazine, minoxidil or nitroprusside.
The use of anaesthetics with other CNS depressant drugs such as those used for premedication may produce synergistic effects on the CNS and, in some cases, a smaller dose of general anaesthetic should be used. Bradycardia occurring during anaesthetic induction with thiopental has been reported in patients also receiving fentanyl.
Herbal medicines: Animal data suggest valerian and St John’s Wort may prolong the effect of thiopental sodium.
Section 4.6
...Thiopental sodium readily crosses the placental barrier...However, when considering use of thiopental sodium the clinician should only use...
Section 4.8
The first paragraph remains the same, however the subsequent 3 paragraphs (paragraphs 2, 3 and 4) have been removed and replaced with: Excessive doses are associated with hypothermia and profound cerebral impairment.
An initial fall in blood pressure is often seen.
Postoperative vomiting is infrequent, but shivering may occur and there may be persistent drowsiness, confusion and amnesia.
Other relatively common postoperative effects include anorexia, malaise, fatigue, and dizziness. Delirium has been noted in elderly patients.
Allergic reactions, skin reactions and hypersensitivity have been rarely reported.
Bronchospasm, respiratory depression and myocardial depression or cardiac arrhythmias may occur.
Headache is also reported with the use of barbiturate anaesthetics.
Section 5.1
First paragraph: Thiopental sodium is a short-acting...
Second paragraph: Thiopental sodium acts through the CNS...
Section 5.2
Second paragraph: Thiopental sodium is strongly bound to plasma protein...Thiopental sodium, therefore, whilst having...
Section 6.2
Title change from "Incompatibilities" to: Major Incompatibilities
...Solutions of thiopental sodium injection have...
Section 6.5
"...Pack size: 1,10 or 25 vials per pack. Not all pack sizes may be marketed"
Section 7
Changed to:
Archimedes Pharma UK Limited
250 South Oak Way
Green Park
Reading
Berkshire
RG2 6UG
UK
Section 10
Date of revision of text has changed
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