Section 2: Scientific Principles
Part B: Intravenous Anesthetics
Chapter 9: Nonbarbiturate Intravenous Anesthetics

Side Effects and Contraindications

The common psychologic emergence reactions are discussed earlier. Contraindications to ketamine relate to specific pharmacologic actions and patient diseases. Patients with increased ICP and with intracranial mass lesions should not receive ketamine because it can increase ICP and has been reported to cause apnea on this basis. 231  The S-(+) enantiomer also increases CBF and is probably similarly contraindicated. 232  Ketamine is also contraindicated in patients with an open eye injury or other ophthalmologic disorder, in whom a ketamine-induced increase in intraocular pressure would be detrimental (Ch. 63). Because ketamine has a propensity to cause hypertension and tachycardia, with a commensurate increase in myocardial oxygen consumption, it is contraindicated as the sole anesthetic in patients with ischemic heart disease. 181  Likewise, it is unwise to give ketamine to patients with vascular aneurysms because of the possible sudden change in arterial pressure. Psychiatric disease such as schizophrenia or a history of adverse reaction to ketamine or one of its congeners also constitutes a contraindication. 119  One should also consider carefully using ketamine when there is a possibility of postoperative delirium from other causes (e.g., delirium tremens, possibility of head trauma) and a ketamine-induced psychomimetic effect would cloud the differential diagnosis.

Other side effects include potentiation of nondepolarizing neuromuscular blockade by an undefined mechanism. 233, 234  Finally, because ketamine‘s preservative, chlorobutanol, has been demonstrated to be neurotoxic, subarachnoid administration is contraindicated. 235  It is probably unwise to administer the drug epidurally for this reason.