Thiopentone is C/I in
Barbiturates promote aminolevulinic acid synthetase, which stimulates the formation of porphyrin (an intermediary in heme synthesis). This may precipitate acute intermittent porphyria or variegate porphyria in susceptible individuals. Barbiturates incompletely depress airway reflex responses to laryngoscopy and intubation, and airway instrumentation may lead to bronchospasm (in asthmatic patients) or laryngospasm in lightly anesthetized patients. In situations where the baroreceptor response will be blunted or absent (eg, hypovolemia, congestive hea failure, b-adrenergic blockade), cardiac output and aerial blood pressure may fall dramatically due to uncompensated peripheral pooling of blood and direct myocardial depression. Ref: Morgan & Mikhail's clinical anesthesiology 6e
Acute intermittent porphyria
Bronchial asthma
Shock
All the above
General anaesthesia