All are true about ketamine except
Ketamine increases all the pressures. i.e intracranial pressure, intraocular pressure, blood pressure, intragastric pressure. With the rise in CBF and the generalized increase in sympathetic nervous system response, ICP increases after ketamine use. The increase in CMRO2 and CBF can be blocked by the use of thiopental or diazepam. The received dogma about ketamine is that it increases cerebral oxygen consumption, cerebral blood flow, and intracranial pressure. These effects would seem to preclude its use in patients with space-occupying intracranial lesions such as occur with head trauma; however, recent publications offer convincing evidence that when combined with a benzodiazepine (or another agent acting on the same GABA receptor system) and controlled ventilation (in techniques that exclude nitrous oxide), ketamine is not associated with increased intracranial pressure. Ketamine increases aerial blood pressure, hea rate, and cardiac output, paicularly after rapid bolus injections. These indirect cardiovascular effects are due to the central stimulation of the sympathetic nervous system and inhibition of the reuptake of norepinephrine after release at nerve terminals. Accompanying these changes are increases in pulmonary aery pressure and myocardial work Ref: Miller's anesthesia 8th edition Ref: Morgan & Mikhail's clinical anesthesiology 6e
Increases ICT
Decreases blood pressure
Increases intraocular pressure
Increases intragastric pressure
General anaesthesia