Halothane vs Sevoflurane

	Halothane	Sevoflurane
Chemical structure	Halogenated alkane	Fluorinated methyl isopropyl ether
Odour	Both drugs have a sweet odour
Preservative for storage	Yes (thymol)	No
Blood: gas partition coefficient	High (2.4) Slower rate of induction and recovery	Lower (0.69) Rapid induction and recovery
MAC	0.75 (more potent)	2 (less potent)
CNS effects	·         Hypoxic ventilator drive is severely depressed by halothane. ·         Blunts autoregulation and increases cerebral blood flow. ·         Maximum increase in CBF among currently used volatile agents	Causes an increase in CBF but to a lesser extent as compared to halothane.
CVS effects	Causes more severe cardiac depression ·         Direct myocardial depression resulting in dose dependent decrease in BP ·         Decreases coronary blood flow due to fall of BP ·         Attenuates Baroreceptor reflex thus blunting the ability to maintain cardiac output by increasing heart rate (like an inhalational β-blocker) ·         Sensitized heart to arrythmogenic effects of catecholamines (epinephrine).	More cardiac stable ·         Comparatively less depression of myocardial contractility ·         Mild decrease in systemic vascular resistance at equipotent dose ·         Does not sensitize the heart to catecholamines.
Hepatic effects	·         Decreases hepatic blood flow ·         Hepatotoxic especially on frequent repeated exposure—halothane hepatitis	·         Decreases portal venous flow but, increases hepatic artery flowà so overall, hepatic blood flow is maintained
Renal effects	·         Decreases renal blood flow, GFR and urinary output ·         Reduction in renal blood flow is more as compared to reduction in GFR resulting in an increase in filtration fraction	·         Slight decrease in renal blood flow, GFR and urine output—comparatively to a lesser degree ·         Reacts with dry barium hydroxide (baralyme) resulting in production of Compound A—found nephrotoxic in animal studies.
On children	·         Less emergence reaction ·         Less nausea/vomiting postoperative	·         More emergence reaction ·         Comparatively more nausea/vomiting postoperative
Upper limit of concomitant epinephrine use	1.5 mcg/kg	4.5mcg/kg
Drug interactions	·         Potentiates non-depolarising neuromuscular blockers ·         Exaggerated myocardial depression when used with beta blockers (eg propranolol) and calcium channel blockers (eg verapamil) ·         Increased lability of BP when used in patients receiving tricyclic antidepressants and monoamine oxidase inhibitors ·         Increased incidence of arrhythmia when combined with aminophylline	·         Potentiates non-depolarising neuromuscular blockers ·         Otherwise, significant drug interaction among other commonly used drugs in clinical practice
Malignant hyperthermia	Both drugs can trigger an attack

Awake Intubation (procedure in brief)