Compare drugs side-by-side

Pick 2-5 drugs to compare mechanism, dosing, PK, hemodynamics, side effects, and pearls. Useful for picking between induction agents, vasoactives, or NMBAs.

	Phenylephrine	Norepinephrine Levophed	Epinephrine Adrenalin	Ephedrine (generic)
Class	Synthetic α1-agonist	Endogenous catecholamine, α1 > β1 agonist	Endogenous catecholamine, α + β agonist	Indirect + direct mixed alpha + beta sympathomimetic
Mechanism	Pure α1 agonist → vasoconstriction. No β activity.	Strong α1 → vasoconstriction. Mild β1 → modest inotropy. Minimal β2.	α1 (vasoconstriction), α2, β1 (inotropy + chronotropy), β2 (bronchodilation, vasodilation in skeletal muscle). Dose-dependent receptor preference: low-dose β-predominant, high-dose α-predominant.	Indirect-acting sympathomimetic — promotes release of stored norepinephrine from presynaptic vesicles AND has direct alpha + beta receptor agonism. Mixed action → increases HR (β1) + contractility (β1) + SVR (α1). Tachyphylaxis develops with repeated dosing (depleted NE stores).
Indications	· Anesthesia-induced hypotension · OB spinal hypotension (preferred over ephedrine for fetal pH) · Mydriasis (ophthalmic)	· Septic shock (first-line) · Vasoplegic shock post-bypass · Distributive shock · Anesthesia-induced hypotension (refractory)	· Anaphylaxis · Cardiac arrest · Hemodynamic support / inotropy · Bronchospasm	· Hypotension during anesthesia, especially with bradycardia (treats both HR + BP) · Hypotension after spinal/epidural anesthesia (alternative to phenylephrine, especially in non-OB) · Symptomatic hypotension in cardiac surgery (vasoconstrictor + inotropic support)
Dosing	Bolus: 50–200 mcg IV Infusion (general OR): 0.15–1.5 mcg/kg/min OB spinal prophylaxis (SOAP 2018): 25–50 mcg/min infusion at spinal placement; titrate to baseline SBP; OR variable-rate 50 mcg bolus PRN	Infusion: 0.01–1 mcg/kg/min (titrated to MAP)	Anaphylaxis IM: 0.3–0.5 mg IM (1:1000) · peds 0.01 mg/kg IM Anaphylaxis IV titrated: 10–100 mcg IV q1–2 min Cardiac arrest: 1 mg IV q3–5 min · peds 0.01 mg/kg IV q3–5 min Inotrope infusion: 0.02–0.5 mcg/kg/min	Hypotension bolus: 5–10 mg IV; can repeat q3–5 min (max ~50 mg/session before tachyphylaxis) · peds 0.1–0.2 mg/kg IV; can repeat q3–5 min IM bolus (no IV): 25–50 mg IM · peds 0.5 mg/kg IM
PK (onset / duration)	Onset 1 min. Duration 10–20 min.	Onset seconds. Duration < 5 min after infusion stop.	Onset seconds. Duration 5–10 min. Catecholamine reuptake + COMT/MAO degradation.	Onset 1-2 min IV. Duration 10-15 min. Renal excretion (~95% unchanged). Half-life 3-6 h. Crosses placenta (use during cesarean — historical concern about fetal acidemia at high doses, but practically OK at standard doses).
Hemodynamics	↑SVR, ↑BP. Reflex bradycardia (often ↓CO).	↑SVR, ↑BP, slight ↑CO. Reflex bradycardia rare.	↑HR, ↑contractility, ↑CO. SVR ↑ at high dose, ↓ at low dose (β2). Can paradoxically ↓BP at very low doses.	↑HR, ↑contractility, ↑SVR → ↑BP. Useful for hypotension + bradycardia (in contrast to phenylephrine which is pure alpha → may cause reflex bradycardia).
Respiratory	—	—	Bronchodilation. Decongestant (mucosal vasoconstriction).	—
Side effects	· Bradycardia + ↓CO (relevant in poor LV function) · Reduced uteroplacental flow at high dose	· Distal ischemia (digits, mesenteric — especially with high-dose, prolonged) · Extravasation necrosis — treat with phentolamine · Reduced renal/splanchnic perfusion at high dose	· Tachyarrhythmias · Hyperglycemia · Lactic acidosis · Tissue ischemia at extravasation site (treat with phentolamine local infiltration) · Pulmonary edema (high-dose, prolonged)	· Tachycardia (problematic in CAD, AS) · Tachyphylaxis (depletion of stored norepinephrine) · Hypertension overshoot if dosed too aggressively · Catecholamine-like effects: tremor, anxiety in awake patient · Possible MI in susceptible patients (catecholamine-driven)
Contraindications	· Severe LV dysfunction (relative — reduced CO with vasoconstriction)	· Hypovolemic shock without volume resuscitation (relative)	· None for life-threatening indications	· Tachyarrhythmia · Severe HTN, pheochromocytoma (uncontrolled catecholamine surge) · Concurrent MAOI use (severe HTN crisis)
Reversal	—	—	—	—
Pearls	· OB spinal: phenylephrine maintains umbilical artery pH better than ephedrine. · Cardiac surgery off-pump: phenyl preferred for systemic pressure during graft anastomoses. · Watch for reflex bradycardia in LVH/HOCM patients.	· Surviving Sepsis: NE first-line, MAP target ≥ 65. · Central line preferred but a peripheral 18g + close monitoring acceptable for short courses (recent literature).	· Anaphylaxis: IM lateral thigh fastest absorption; IV in resuscitation only. · LAST: drop epi to ≤1 mcg/kg (≤100 mcg). · Caution: with halothane ('sensitized myocardium' — but halothane is rarely used in 2026).	· FIRST-LINE for hypotension WITH BRADYCARDIA in non-OB cases — treats both HR + BP. If hypotension WITHOUT bradycardia or with tachycardia, phenylephrine is preferred. · Cesarean spinal hypotension: PHENYLEPHRINE infusion is preferred over ephedrine boluses (Ngan Kee Anesth Analg 2010 — less fetal acidemia). Ephedrine has fallen from first-line in OB. · TACHYPHYLAXIS: after 3-4 boluses, switch to phenylephrine or norepinephrine (works on different mechanism — direct receptor agonism unaffected by NE depletion). · MAOI patients: indirect-acting sympathomimetics → catecholamine SURGE (norepinephrine pool not metabolized normally) → severe HTN crisis. Use direct-acting (phenylephrine, norepinephrine) instead.

Common compares

Propofol vs Etomidate vs Ketamine Sux vs Roc vs Cis Fentanyl vs Remi Phenylephrine vs Norepi Volatiles

Cells showing "—" indicate the drug doesn't have a detail entry for that field yet (most drugs do; some legacy class members haven't been fully populated). Education only — verify dosing against package insert + institutional protocol before bedside use.

Compare drugs side-by-side

Pick 2-5 drugs to compare mechanism, dosing, PK, hemodynamics, side effects, and pearls. Useful for picking between induction agents, vasoactives, or NMBAs.

	Phenylephrine	Norepinephrine Levophed	Epinephrine Adrenalin	Ephedrine (generic)
Class	Synthetic α1-agonist	Endogenous catecholamine, α1 > β1 agonist	Endogenous catecholamine, α + β agonist	Indirect + direct mixed alpha + beta sympathomimetic
Mechanism	Pure α1 agonist → vasoconstriction. No β activity.	Strong α1 → vasoconstriction. Mild β1 → modest inotropy. Minimal β2.	α1 (vasoconstriction), α2, β1 (inotropy + chronotropy), β2 (bronchodilation, vasodilation in skeletal muscle). Dose-dependent receptor preference: low-dose β-predominant, high-dose α-predominant.	Indirect-acting sympathomimetic — promotes release of stored norepinephrine from presynaptic vesicles AND has direct alpha + beta receptor agonism. Mixed action → increases HR (β1) + contractility (β1) + SVR (α1). Tachyphylaxis develops with repeated dosing (depleted NE stores).
Indications	· Anesthesia-induced hypotension · OB spinal hypotension (preferred over ephedrine for fetal pH) · Mydriasis (ophthalmic)	· Septic shock (first-line) · Vasoplegic shock post-bypass · Distributive shock · Anesthesia-induced hypotension (refractory)	· Anaphylaxis · Cardiac arrest · Hemodynamic support / inotropy · Bronchospasm	· Hypotension during anesthesia, especially with bradycardia (treats both HR + BP) · Hypotension after spinal/epidural anesthesia (alternative to phenylephrine, especially in non-OB) · Symptomatic hypotension in cardiac surgery (vasoconstrictor + inotropic support)
Dosing	Bolus: 50–200 mcg IV Infusion (general OR): 0.15–1.5 mcg/kg/min OB spinal prophylaxis (SOAP 2018): 25–50 mcg/min infusion at spinal placement; titrate to baseline SBP; OR variable-rate 50 mcg bolus PRN	Infusion: 0.01–1 mcg/kg/min (titrated to MAP)	Anaphylaxis IM: 0.3–0.5 mg IM (1:1000) · peds 0.01 mg/kg IM Anaphylaxis IV titrated: 10–100 mcg IV q1–2 min Cardiac arrest: 1 mg IV q3–5 min · peds 0.01 mg/kg IV q3–5 min Inotrope infusion: 0.02–0.5 mcg/kg/min	Hypotension bolus: 5–10 mg IV; can repeat q3–5 min (max ~50 mg/session before tachyphylaxis) · peds 0.1–0.2 mg/kg IV; can repeat q3–5 min IM bolus (no IV): 25–50 mg IM · peds 0.5 mg/kg IM
PK (onset / duration)	Onset 1 min. Duration 10–20 min.	Onset seconds. Duration < 5 min after infusion stop.	Onset seconds. Duration 5–10 min. Catecholamine reuptake + COMT/MAO degradation.	Onset 1-2 min IV. Duration 10-15 min. Renal excretion (~95% unchanged). Half-life 3-6 h. Crosses placenta (use during cesarean — historical concern about fetal acidemia at high doses, but practically OK at standard doses).
Hemodynamics	↑SVR, ↑BP. Reflex bradycardia (often ↓CO).	↑SVR, ↑BP, slight ↑CO. Reflex bradycardia rare.	↑HR, ↑contractility, ↑CO. SVR ↑ at high dose, ↓ at low dose (β2). Can paradoxically ↓BP at very low doses.	↑HR, ↑contractility, ↑SVR → ↑BP. Useful for hypotension + bradycardia (in contrast to phenylephrine which is pure alpha → may cause reflex bradycardia).
Respiratory	—	—	Bronchodilation. Decongestant (mucosal vasoconstriction).	—
Side effects	· Bradycardia + ↓CO (relevant in poor LV function) · Reduced uteroplacental flow at high dose	· Distal ischemia (digits, mesenteric — especially with high-dose, prolonged) · Extravasation necrosis — treat with phentolamine · Reduced renal/splanchnic perfusion at high dose	· Tachyarrhythmias · Hyperglycemia · Lactic acidosis · Tissue ischemia at extravasation site (treat with phentolamine local infiltration) · Pulmonary edema (high-dose, prolonged)	· Tachycardia (problematic in CAD, AS) · Tachyphylaxis (depletion of stored norepinephrine) · Hypertension overshoot if dosed too aggressively · Catecholamine-like effects: tremor, anxiety in awake patient · Possible MI in susceptible patients (catecholamine-driven)
Contraindications	· Severe LV dysfunction (relative — reduced CO with vasoconstriction)	· Hypovolemic shock without volume resuscitation (relative)	· None for life-threatening indications	· Tachyarrhythmia · Severe HTN, pheochromocytoma (uncontrolled catecholamine surge) · Concurrent MAOI use (severe HTN crisis)
Reversal	—	—	—	—
Pearls	· OB spinal: phenylephrine maintains umbilical artery pH better than ephedrine. · Cardiac surgery off-pump: phenyl preferred for systemic pressure during graft anastomoses. · Watch for reflex bradycardia in LVH/HOCM patients.	· Surviving Sepsis: NE first-line, MAP target ≥ 65. · Central line preferred but a peripheral 18g + close monitoring acceptable for short courses (recent literature).	· Anaphylaxis: IM lateral thigh fastest absorption; IV in resuscitation only. · LAST: drop epi to ≤1 mcg/kg (≤100 mcg). · Caution: with halothane ('sensitized myocardium' — but halothane is rarely used in 2026).	· FIRST-LINE for hypotension WITH BRADYCARDIA in non-OB cases — treats both HR + BP. If hypotension WITHOUT bradycardia or with tachycardia, phenylephrine is preferred. · Cesarean spinal hypotension: PHENYLEPHRINE infusion is preferred over ephedrine boluses (Ngan Kee Anesth Analg 2010 — less fetal acidemia). Ephedrine has fallen from first-line in OB. · TACHYPHYLAXIS: after 3-4 boluses, switch to phenylephrine or norepinephrine (works on different mechanism — direct receptor agonism unaffected by NE depletion). · MAOI patients: indirect-acting sympathomimetics → catecholamine SURGE (norepinephrine pool not metabolized normally) → severe HTN crisis. Use direct-acting (phenylephrine, norepinephrine) instead.