Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
LEVOPHED vs RISPERDAL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Norepinephrine acts predominantly on alpha-1 adrenergic receptors to cause vasoconstriction and increase blood pressure. It also has beta-1 adrenergic receptor agonist activity, resulting in positive inotropic effects on the heart.
Risperidone is a benzisoxazole atypical antipsychotic that antagonizes dopamine D2 and serotonin 5-HT2A receptors. It also blocks alpha1-adrenergic, alpha2-adrenergic, and histamine H1 receptors.
Treatment of hypotension in acute hypotensive states (e.g., septic shock, myocardial infarction, blood loss),Adjunct in the treatment of cardiac arrest (off-label)
Schizophrenia (FDA-approved),Bipolar I disorder (acute manic or mixed episodes) (FDA-approved),Irritability associated with autistic disorder (FDA-approved),Treatment-resistant depression (adjunctive to antidepressants) (off-label),Tourette's disorder (off-label),Obsessive-compulsive disorder (adjunctive) (off-label),Post-traumatic stress disorder (off-label),Delirium (off-label)
Initial dose: 8-12 mcg/min intravenously, titrate to desired blood pressure; typical maintenance: 2-4 mcg/min IV continuous infusion.
2-8 mg orally once daily or divided twice daily; maximum 16 mg/day
The terminal elimination half-life is approximately 2 minutes. The clinical effect is short-lived due to rapid reuptake and metabolism; continuous intravenous infusion is required for sustained effect.
20 hours (parent drug), 23 hours (active metabolite 9-hydroxyrisperidone). Steady state reached in 5-6 days. Extended in elderly and hepatic/renal impairment.
Primarily metabolized in the liver by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO).
Risperidone is extensively metabolized by cytochrome P450 2D6 (CYP2D6) to its active metabolite, 9-hydroxyrisperidone (paliperidone). A minor pathway involves CYP3A4 and CYP3A5. The metabolite is further metabolized via N-dealkylation and oxidative pathways.
Norepinephrine is primarily metabolized in the liver and other tissues by catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO). Less than 5% is excreted unchanged in urine. Metabolites are excreted renally (approximately 80-95% as normetanephrine, vanillylmandelic acid, and other conjugates).
Renal: 70% (30% as unchanged drug, 40% as metabolites), Fecal/Biliary: 14%
Approximately 25-30% bound to albumin and other plasma proteins.
90% (albumin and alpha-1-acid glycoprotein). Active metabolite 77% bound.
Approximately 0.7-1.0 L/kg. This indicates moderate distribution into tissues and plasma, consistent with a hydrophilic catecholamine.
1-2 L/kg. Large Vd indicates extensive tissue distribution and penetration into CNS.
Bioavailability is 100% via intravenous administration. Oral bioavailability is negligible due to extensive first-pass metabolism; not administered orally. Intramuscular or subcutaneous administration results in erratic absorption and significant vasoconstriction leading to poor bioavailability; thus, intravenous infusion is the only reliable route.
Oral: 70% (with extensive first-pass metabolism). IM: 100% for immediate-release. Long-acting IM: fraction absorbed over depot injection.
No specific dose adjustment required for renal impairment; titrate to clinical response.
Cr Cl <30 m L/min: initial 0.5 mg twice daily, increase by 0.5 mg increments; max 3 mg/day
No specific dose adjustment required for hepatic impairment; titrate to clinical response.
Child-Pugh class A or B: initial 0.5 mg twice daily, increase by 0.5 mg increments; max 3 mg/day; Child-Pugh C: not studied
Initial: 0.05-0.1 mcg/kg/min IV continuous infusion, titrate to effect; maximum dose not established.
13-17 yr: 0.5 mg once daily, titrate by 0.5-1 mg/day at ≥24 hr intervals; target 3 mg/day; max 6 mg/day. 10-12 yr: 0.5 mg once daily, titrate by 0.5 mg/day; target 1-2.5 mg/day; max 3 mg/day
Start at lower end of dosing range (2-4 mcg/min IV) due to increased sensitivity and comorbidities; titrate cautiously.
Initial 0.5 mg twice daily; increase by 0.5 mg increments; max 3 mg/day; monitor for orthostatic hypotension and sedation
No FDA boxed warning exists for LEVOPHED.
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Risperidone is not approved for the treatment of dementia-related psychosis.
Risk of extravasation leading to tissue necrosis; ensure proper IV access and avoid infiltration,Monitor blood pressure, heart rate, and cardiac output continuously,May cause ischemia to limbs, kidneys, and splanchnic organs due to vasoconstriction,Use with caution in patients with hypertension, hyperthyroidism, or myocardial ischemia,Abrupt discontinuation may cause rebound hypotension
Increased mortality in elderly patients with dementia-related psychosis,Cerebrovascular adverse events (e.g., stroke, transient ischemic attack) in elderly with dementia,Neuroleptic malignant syndrome (NMS),Tardive dyskinesia,Hyperglycemia and diabetes mellitus,Weight gain,Dyslipidemia,Orthostatic hypotension and syncope,Seizures,Leukopenia, neutropenia, and agranulocytosis,QT interval prolongation,Hyperprolactinemia,Body temperature dysregulation,Dysphagia,Priapism,Thrombotic thrombocytopenic purpura (TTP)
Hypersensitivity to norepinephrine or any component of the formulation,Hypovolemia (should be corrected before or during therapy),Use with cyclopropane or halothane anesthesia (increases risk of ventricular arrhythmias),Severe peripheral vascular disease with risk of gangrene
Hypersensitivity to risperidone, paliperidone, or any component of the formulation
No clinically significant food interactions. Monitor for hyperglycemia in diabetic patients due to alpha-adrenergic effects.
Grapefruit juice may increase risperidone levels; avoid concurrent use. Risperidone can be taken with or without food. High-fat meals do not affect absorption. Weight gain is common; encourage heart-healthy diet. Alcohol may exacerbate CNS depression and orthostatic hypotension; advise avoidance.
Norepinephrine is a catecholamine that does not cross the placenta extensively. Animal studies have not shown teratogenicity, but human data are limited. Inadequate uteroplacental blood flow due to maternal vasoconstriction may cause fetal hypoxia and bradycardia. Use only if clearly needed, and monitor fetal heart rate. FDA Pregnancy Category C.
First trimester: Limited human data; animal studies show no evidence of teratogenicity at clinically relevant doses. Second and third trimesters: Risk of extrapyramidal symptoms and/or withdrawal symptoms in neonates if exposed during third trimester. Overall, not considered a major teratogen.
Norepinephrine is not expected to be excreted into breast milk in clinically significant amounts due to its short half-life and rapid metabolism. M/P ratio not established. Use with caution in breastfeeding women, as effects on the infant are unknown.
Risperidone and its active metabolite 9-hydroxyrisperidone are excreted in breast milk. Milk-to-plasma ratio (M/P) approximately 0.42-0.44. Relative infant dose is about 4-9% of maternal weight-adjusted dose. Monitor infant for sedation, poor feeding, and extrapyramidal symptoms. Consider benefits of breastfeeding vs. risk.
Pregnancy may alter the pharmacokinetics of norepinephrine, but specific dose adjustments are not established. Monitor maternal blood pressure closely and titrate to the lowest effective dose to maintain adequate uteroplacental perfusion. Starting dose is typically 0.5-1 mcg/min, titrated to effect.
Increased plasma volume and hepatic metabolism may lower risperidone concentrations, especially in second and third trimesters. Dose adjustments may be needed; monitor clinical response and consider therapeutic drug monitoring. No standard dose adjustment recommendation; titrate to effect.
LEVOPHED (norepinephrine) is a first-line vasopressor for septic shock. Administer via central line to avoid extravasation injury; if extravasation occurs, treat with phentolamine 5-10 mg in 10 m L saline infiltrated locally. Titrate to mean arterial pressure (MAP) ≥ 65 mm Hg. Taper gradually to avoid rebound hypotension.
Risperdal (risperidone) is a second-generation antipsychotic with high affinity for D2 and 5-HT2A receptors. Monitor for orthostatic hypotension during dose titration, especially in elderly. QT prolongation risk is dose-dependent; avoid with hypokalemia, hypomagnesemia, or concomitant QT-prolonging drugs. Therapeutic response for psychosis may take 2-4 weeks. For agitation, consider sublingual or IM formulations. Extrapyramidal symptoms are dose-related; more common at doses >6 mg/day. Prolactin elevation is more pronounced than with other atypical antipsychotics; monitor for galactorrhea, gynecomastia, menstrual irregularities. Weight gain and metabolic syndrome require baseline and periodic monitoring of BMI, fasting glucose, and lipids. Risk of tardive dyskinesia with long-term use. In elderly with dementia-related psychosis, increased mortality.
This medication is used to treat dangerously low blood pressure.,It will be given intravenously (IV) in a hospital setting by healthcare professionals.,You may feel anxiety, headache, or heart palpitations as the medication works.,Report any pain, redness, or swelling at the IV site immediately.,Do not stop the medication abruptly; it must be tapered under medical supervision.
Take risperidone exactly as prescribed; do not crush or chew tablets.,Avoid alcohol and grapefruit juice as they may worsen side effects.,Rise slowly from sitting or lying to prevent dizziness or fainting.,Report unusual muscle stiffness, tremors, or restlessness immediately.,Notify your doctor if you experience breast swelling, discharge, or sexual dysfunction.,Risperidone may cause drowsiness; avoid driving until you know how the drug affects you.,Do not stop abruptly; withdrawal may cause nausea, vomiting, or insomnia.,Use effective contraception if of childbearing potential; discuss pregnancy plans with your doctor.,Avoid overheating or dehydration; increased body temperature may occur.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about LEVOPHED vs RISPERDAL, answered by our medical review team.
LEVOPHED is a Vasopressor that works by Norepinephrine acts predominantly on alpha-1 adrenergic receptors to cause vasoconstriction and increase blood pressure. It also has beta-1 adrenergic receptor agonist activity, resulting in positive inotropic effects on the heart.. RISPERDAL is a Atypical Antipsychotic that works by Risperidone is a benzisoxazole atypical antipsychotic that antagonizes dopamine D2 and serotonin 5-HT2A receptors. It also blocks alpha1-adrenergic, alpha2-adrenergic, and histamine H1 receptors.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between LEVOPHED and RISPERDAL depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of LEVOPHED is: Initial dose: 8-12 mcg/min intravenously, titrate to desired blood pressure; typical maintenance: 2-4 mcg/min IV continuous infusion.. The standard adult dose of RISPERDAL is: 2-8 mg orally once daily or divided twice daily; maximum 16 mg/day. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between LEVOPHED and RISPERDAL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. LEVOPHED is classified as Category C. Norepinephrine is a catecholamine that does not cross the placenta extensively. Animal studies have not shown teratogenicity, but human data are limited. Inadequate uteroplacental . RISPERDAL is classified as Category C. First trimester: Limited human data; animal studies show no evidence of teratogenicity at clinically relevant doses. Second and third trimesters: Risk of extrapyramidal symptoms an. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.