Table 1.

Pharmacological interventions involved in critical ill patients and their pharmacokinetic characteristics

ANALGESICS/SEDATIVE	Half life	Protein binding	Hepatic extraction ratio to blood flow	CYP3A	CYP2C9/19	CYP2D6	Renal elimination	Transporter/OTHERS
Fentanyl	2.5–6.5mins	80–85%	High	√			√
Propofol	30–60mins	95–99%	High				√	CYP2B/UGT
Alfentanil	1.5–2 hrs	92%	Low	√			√
Midazolam	1.8–6.4hrs	95%	Low/Intermediate	√			√
Morphine	2–3hrs	30–40%	High				√	UGT
MUSCLE RELAXANT
Vecuronium	51–80mins	30%	Low	√			√	PGP
Pancuronium	1.5–2.7hrs	77–91%	Low				√ +Bile
ANTI-ARRYTHMICS							√
Lidocaine	1.5–2hrs	61–80%	High	√			√	CYP1A2
Amiodarone	15–142 days	33–65%	Low		√		Bile
Digoxin	38–48hrs	25%	Low				√	PGP
Procainamide	2.5–4.5hrs	15–20%	Intermediate			√	√
Bretylium	7–8hrs	N/A	N/A				√ only
ANTI-HYPERTENSIVE
Verapamil	2.8–7.4hrs	90%	Intermediate	√	√			PGP
Enalapril	11hrs	N/A	Intermediate				√	OATP/MRP2
Metoprolol	3–7hrs	15%	Intermediate/high			√	√
Propranolol	4–5hrs	88%	High			√
Atenolol	6–7hrs	6–16%	Low				√
Valsartan	6hrs	95%	N/A				√+Bile	OATP/MRP2
Pravastatin	77hrs	50%	Intermediate/high				√	OATP1B1/OATP2B1
RESUSCITATION/INCREASE HEART RATE
Epinephrine	2mins	N/A	N/A				√	MAO/COMT
Dopamine	9mins	N/A	N/A					MAO/COMT
ANTI-CONVULSANT
Phenytoin	6–24hrs	90%	Intermediate		√		√+Bile	UGT
Phenobarbital	2–7 days	20–45%	N/A		√		√	CYP2C19/UGT
Carbamazepine	25–65hrs	76%	Low		√			PGP/UGT
MISCELLANEOUS
Warfarin	30–60hrs	99.5%	Low		√ (S−,R−)		√	CYP1A2(R−)
Mannitol	100mins	N/A	N/A				√ only
Gentamicin	2 hrs	0–10%	N/A				√
Rifampin	1.5–5hrs	90–95%	N/A				√	Esterases
Ranitidine	2–3hrs	15%	N/A			√	√	PGP
Famotidine	8–12hrs	10–28%	N/A				√
Corticosteriods	Varies	varies	N/A	√			√
Magnesium Sulfate	N/A	NA	N/A				√ only

Abbreviations: N/A: Not available; mins: Minutes; hrs: Hours; PGP: P-glycoprotein; UGT: UDP-galactose transporter; MAO: monoamine oxydase; COMT: catechol-O-methyltransferase; OATP: organic anion transporter; MRP2: Multidrug resistance protein 2.