Table 5.

Pharmacodynamic and pharmacokinetic properties of propofol and ketamine

Medication	Metabolism	Elimination half-life (hours)	Onset after oral dose consumption	Commentsa
Propofol	Hepatic mainly via CYP2B6 to water-soluble sulfate and glucuronide conjugates; also, via CYP1A2, CYP2A6, CYP2C19, CYP2C9, CYP2D6, CYP2E1, and CYP3A4	4–7	1–2 minutes	Cardiovascular and respiratory depression (propofol-related infusion syndrome); hypotensive agent; contraindicated in patients with egg allergy
Ketamine	Hepatic via CYP2B6, CYP2C9, and CYP3A4 to active (norketamine) and non-active metabolites; also, via hepatic conjugation	1–2	30 seconds IV; 3–4 minutes IM	Increased airway secretions and laryngospasm; elevated IOP and ICP; emergence reactions, CNS depressant, sympathetic stimulator (increases HR and BP); psychotomimetic effects (hallucinations and nightmares)

Notes:

^aSpecial care should be taken when administering propofol with alfentanil (due to risk of opisthotonus and/or grand mal seizures), CNS, and respiratory depressants (opioid narcotics, sedatives). Ketamine can worsen cardiovascular toxicity of cocaine and TCAs.

Abbreviations: IV, intravenous; IM, intramuscular; IOP, intraocular pressure; ICP, intracranial pressure; HR, heart rate; BP, blood pressure; CNS, central nervous system.