Canonical Question
PainPharm – NMDA Antagonists
Master answer
| PROPOFOL | KETAMINE | |
|---|---|---|
| Dose for induction | 2-2.5mg/kg 0.5-1mg/kg in critically unwell | 0.5-1.5mg/kg |
| Autonomic nervous system | Reduction in sympathetic outflow | Increase in sympathetic outflow Centrally mediated |
| Heart rate | Blunts baroreceptor reflex → no reflex tachycardia Bradycardia due to reduced sympathetic tone | Increased due to increased sympathetic outflow |
| Contractility | Mild direct negative inotropy Secondary effect due to reduced sympathetic tone | Direct negative inotropy Increased sympathetic tone → increased overall inotropy (providing maximal sympathetic tone has not already been reached by the patient) |
| Peripheral vascular resistance | Direct vasodilation Secondary effect due to reduced sympathetic outflow | Direct vasodilation Overall, increased due to increased sympathetic tone |
| Blood pressure | Decreased | Usually increased |
| Cerebral circulation | Reduced CMRO2 Reduced cerebral blood flow | Increased CMRO2 Increased cerebral blood flow (No way are we diving in to the ICP question in this debate!) |
Exam appearances
| Exam | Exact wording | Relationship | Success |
|---|---|---|---|
| 2007B Q21 | Compare and contrast the cardiovascular effects of an induction dose of Propofol and ketamine. | historical_member | — |