Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
VOSEVI vs ATROPINE AND DEMEROL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
VOSEVI (sofosbuvir, velpatasvir, and voxilaprevir) is a fixed-dose combination of a nucleotide analog NS5B polymerase inhibitor (sofosbuvir), an NS5A inhibitor (velpatasvir), and a NS3/4A protease inhibitor (voxilaprevir). The combination inhibits hepatitis C virus replication by targeting multiple viral proteins.
Atropine is an antimuscarinic agent that competitively blocks acetylcholine at muscarinic receptors, reducing secretions and gastrointestinal motility. Meperidine (Demerol) is an opioid agonist that binds to mu-opioid receptors in the CNS, altering pain perception and producing analgesia.
Treatment of chronic hepatitis C virus genotype 1-6 infection in adults who have no prior treatment with a NS5A inhibitor and have been previously treated with a regimen containing sofosbuvir without a NS5A inhibitor,Treatment of chronic hepatitis C virus genotype 1-6 infection in adults who have prior treatment with a NS5A inhibitor-containing regimen
Preanesthetic medication to reduce secretions and prevent bradycardia,Management of moderate to severe pain (as an opioid analgesic),Off-label: treatment of opioid-induced constipation (meperidine component)
One tablet (sofosbuvir 400 mg/velpatasvir 100 mg/voxilaprevir 100 mg) orally once daily with food for 8 weeks.
Atropine 0.4 mg and Demerol (meperidine) 50-100 mg intramuscularly as preanesthetic medication 30-60 minutes before procedure.
Sofosbuvir: 0.5 h (parent), 27 h (GS-331007 metabolite); Velpatasvir: 17 h; Voxilaprevir: 33 h. Terminal half-lives support once-daily dosing; metabolite GS-331007 accumulates but is less active.
Atropine: 2-4 hours (terminal half-life). Demerol: 2.5-4 hours; normeperidine metabolite half-life 15-30 hours (accumulates in renal impairment).
Sofosbuvir is metabolized by cathepsin A and CES1 to the active metabolite GS-461203, followed by dephosphorylation. Velpatasvir and voxilaprevir are metabolized by CYP2B6, CYP2C8, CYP3A4 (minor). Voxilaprevir is also a substrate of OATP1B1/1B3.
Meperidine is primarily metabolized in the liver via hydrolysis to meperidinic acid and via N-demethylation to normeperidine (active metabolite), involving CYP3A4 and CYP2B6. Atropine is metabolized in the liver via hydrolysis and glucuronidation; approximately 50% is excreted unchanged in urine.
Sofosbuvir: 80% renal, 14% fecal; Velpatasvir: 94% fecal, 0.4% renal; Voxilaprevir: 40% renal, 47% fecal. VOSEVI components are eliminated primarily via biliary/fecal (velpatasvir, voxilaprevir) and renal (sofosbuvir) pathways.
Atropine: approximately 50% excreted unchanged in urine, remainder as metabolites (biliary and renal). Demerol (meperidine): primarily hepatic metabolism; <5% excreted unchanged in urine; metabolites (including normeperidine) excreted renally.
Sofosbuvir: ~85% bound; Velpatasvir: >99.5% bound; Voxilaprevir: >99% bound. Primarily to albumin.
Atropine: ~44% bound to albumin and alpha-1 acid glycoprotein. Demerol: ~60% bound to albumin and alpha-1 acid glycoprotein.
Sofosbuvir: ~1.8 L/kg; Velpatasvir: ~4.9 L/kg; Voxilaprevir: ~3.9 L/kg. Large Vd indicates extensive tissue distribution, including liver (target organ).
Atropine: 1-3 L/kg (large, extensive tissue distribution). Demerol: 3-5 L/kg (large, distributes widely including CNS).
Oral: sofosbuvir ~92%, velpatasvir ~29%, voxilaprevir ~44% (fasted). Administer with food to increase absorption (especially voxilaprevir AUC 2- to 4-fold).
Atropine: oral ~10-25% (extensive first-pass metabolism). Demerol: oral ~50-60% (significant first-pass metabolism). IM/IV 100%.
No dose adjustment required for mild to moderate renal impairment (e GFR ≥30 m L/min/1.73 m²). For severe renal impairment (e GFR <30 m L/min/1.73 m²) or end-stage renal disease, safety and efficacy not established; use not recommended.
Meperidine: GFR 10-50 m L/min: administer 75% of normal dose; GFR <10 m L/min: administer 50% of normal dose and avoid due to normeperidine accumulation. Atropine: no adjustment required.
Contraindicated in Child-Pugh class B or C decompensated cirrhosis due to increased voxilaprevir exposure. No dose adjustment required for Child-Pugh class A cirrhosis.
Meperidine: Child-Pugh A: reduce dose by 25%; Child-Pugh B: reduce by 50%; Child-Pugh C: contraindicated. Atropine: caution in severe hepatic impairment.
Safety and efficacy in pediatric patients <18 years have not been established; no specific dosing recommendations.
Atropine 0.01 mg/kg (max 0.4 mg) and meperidine 1-2 mg/kg (max 100 mg) intramuscularly 30-60 minutes before procedure.
No dose adjustment required based on age. Clinical studies included patients ≥65 years with no overall differences in safety or efficacy; consider renal function monitoring.
Reduce meperidine dose by 50% and avoid in elderly due to risk of seizures and delirium; use alternative opioids. Atropine dose unchanged but monitor for anticholinergic effects.
Risk of hepatitis B virus reactivation in patients coinfected with HCV and HBV. Test all patients for evidence of current or prior HBV infection before starting treatment. Monitor HCV/HBV coinfected patients for hepatitis B reactivation during treatment and post-treatment follow-up.
Meperidine has a boxed warning for risk of respiratory depression, especially in elderly, cachectic, or debilitated patients, and when used with CNS depressants. Also, risk of serotonin syndrome when co-administered with serotonergic drugs, and risk of abuse, addiction, and diversion.
Risk of HBV reactivation,Risk of bradycardia when coadministered with amiodarone; avoid use unless alternatives are not available,Decompensated hepatic impairment: not recommended for use in patients with moderate or severe hepatic impairment (Child-Pugh B or C),Drug interactions: potential for reduced therapeutic effect if given with P-gp inducers (e.g., rifampin) or moderate/strong CYP inducers
Respiratory depression, hypotension, bradycardia, urinary retention, constipation, serotonin syndrome, seizures (normeperidine accumulation), decreased GI motility, drug dependence, and tolerance. Use caution in elderly, renal impairment, hepatic impairment, respiratory disorders, prostatic hyperplasia, glaucoma, and with concurrent CNS depressants.
Concomitant use with rifampin (CYP2B6 and P-gp inducer) due to significant decrease in voxilaprevir concentrations,Concomitant use with St. John's wort (Hypericum perforatum) due to decreased drug concentrations,Coadministration with rosuvastatin is contraindicated due to increased risk of myopathy/rhabdomyolysis,Severe hepatic impairment (Child-Pugh C)
Hypersensitivity to atropine or meperidine; severe asthma or COPD; acute respiratory depression; paralytic ileus; known or suspected gastrointestinal obstruction; patients receiving MAOIs (within 14 days); myasthenia gravis (relative for atropine); increased intraocular pressure (glaucoma); severe renal impairment (normeperidine accumulation).
VOSEVI should be taken with food to ensure adequate absorption. A high-fat meal (approximately 800–1000 calories, 50% fat) increases absorption of velpatasvir and voxilaprevir. Avoid concurrent use with St. John's wort, rifampin, and other P-glycoprotein inducers, as they may reduce VOSEVI efficacy.
Avoid alcohol. Meperidine may interact with foods containing tyramine (aged cheeses, cured meats) in patients on MAOIs; otherwise no significant food interactions.
VOSEVI is contraindicated in pregnancy due to risk of fetal harm. No adequate human data; animal studies show developmental toxicity at clinically relevant exposures. Use effective contraception during treatment and for 6 months after completion.
Atropine: FDA Pregnancy Category C. Crosses placenta; may cause fetal tachycardia. Demerol (meperidine): FDA Pregnancy Category C. First trimester: limited human data; animal studies show no teratogenicity. Second trimester: no specific risks. Third trimester: use near term may cause neonatal respiratory depression, decreased Apgar scores, and withdrawal symptoms. Chronic use may lead to neonatal opioid withdrawal syndrome (NOWS).
No data on presence in human milk; animal studies indicate excretion. M/P ratio unknown. Risk of adverse effects in infant not excluded; advise against breastfeeding during therapy.
Atropine: Excreted in breast milk in small amounts; may inhibit lactation. M/P ratio not established. Use with caution; monitor infant for anticholinergic effects (tachycardia, dry mouth). Demerol: Excreted in breast milk; relative infant dose (RID) ~0.5-0.8% of maternal weight-adjusted dose. M/P ratio 1.0-1.6. Limited data; avoid in breastfeeding due to potential neonatal sedation and respiratory depression. American Academy of Pediatrics considers meperidine compatible but caution advised.
No data on pharmacokinetic changes in pregnancy; dose adjustments not established. VOSEVI is not recommended in pregnancy; if inadvertent exposure occurs, consult specialist.
Atropine: No specific dose adjustments recommended; increased volume of distribution may require higher doses for effect. Demerol: Increased clearance and volume of distribution in pregnancy; standard doses may be less effective. Avoid use during labor due to risk of neonatal respiratory depression; if necessary, use lowest effective dose and monitor neonate. No specific dose reduction recommended, but caution with repeated doses.
VOSEVI is a fixed-dose combination of sofosbuvir (NS5B inhibitor), velpatasvir (NS5A inhibitor), and voxilaprevir (NS3/4A protease inhibitor) indicated for treatment-naive and treatment-experienced patients with chronic HCV genotype 1–6 without cirrhosis or with compensated cirrhosis. It is particularly useful for patients who have failed prior NS5A inhibitor-containing regimens, including those with genotype 3 and compensated cirrhosis. Monitor for hepatitis B reactivation in HBV co-infected patients. Dose adjustment not required for mild or moderate renal impairment, but safety not established in severe renal impairment or ESRD. Caution with amiodarone due to risk of serious bradycardia. Check for drug interactions with P-gp inducers, CYP2B6, CYP2C8, and CYP3A4 substrates.
Atropine and Demerol (meperidine) combination is used for pre-anesthetic medication to reduce secretions and produce sedation. Monitor for CNS depression, respiratory depression, and anticholinergic effects (tachycardia, dry mouth, urinary retention). Use cautiously in elderly, patients with COPD, asthma, or prostatic hyperplasia. Avoid in patients with MAOIs due to risk of serotonin syndrome.
Take VOSEVI exactly as prescribed, usually one tablet once daily with food.,Do not skip doses or stop taking VOSEVI without talking to your doctor.,If you have hepatitis B co-infection, your doctor will monitor you for HBV reactivation during and after treatment.,Tell your doctor about all medications, including over-the-counter drugs, herbal supplements, and vitamins, as VOSEVI may interact with them.,Common side effects include headache, fatigue, diarrhea, and nausea. Contact your doctor if you experience severe abdominal pain, jaundice, or signs of liver injury.,VOSEVI does not prevent transmission of HCV. Practice safe sex and avoid sharing needles to reduce the risk of spreading the virus.
This medication may cause drowsiness, dizziness, or blurred vision; avoid driving or operating machinery until effects are known.,Avoid alcohol and other CNS depressants while taking this medication.,Report difficulty urinating, fast heartbeat, or severe constipation to your healthcare provider.,Do not take more than prescribed; risk of dependence with long-term use.,Keep out of reach of children; may cause serious breathing problems if accidentally taken.
No interactions on record
"Rivastigmine, a reversible carbamate acetylcholinesterase inhibitor, increases synaptic acetylcholine levels, enhancing cholinergic transmission. Atropine, a competitive antagonist of muscarinic acetylcholine receptors, blocks the effects of acetylcholine at these receptors, leading to reduced parasympathetic activity. When used together, atropine can diminish the therapeutic efficacy of rivastigmine by pharmacodynamically antagonizing its cholinergic effects, particularly in the central nervous system and peripheral muscarinic receptors, potentially worsening cognitive function in Alzheimer's disease patients."
"Umeclidinium, a long-acting muscarinic antagonist (LAMA), and atropine, a non-selective muscarinic antagonist, both block the action of acetylcholine at muscarinic receptors in the parasympathetic nervous system. Their co-administration leads to additive anticholinergic effects, resulting in an increased risk of peripheral anticholinergic adverse effects such as dry mouth, blurred vision, constipation, urinary retention, and tachycardia, as well as central nervous system effects like confusion or delirium, especially in elderly patients. Clinically, this combination may also exacerbate conditions such as angle-closure glaucoma or paralytic ileus."
"Concurrent use of atropine and gallamine triethiodide results in additive antagonism at muscarinic acetylcholine receptors, leading to enhanced blockade of parasympathetic effects and increased risk of tachycardia, hypertension, and delirium. Atropine, a competitive antagonist of muscarinic receptors, counteracts the vagolytic effects of gallamine, a nondepolarizing neuromuscular blocker that also exhibits weak vagolytic activity. This pharmacodynamic interaction can cause severe sinus tachycardia, hypertension, and central anticholinergic syndrome, especially in elderly patients or those with cardiovascular disease."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about VOSEVI vs ATROPINE AND DEMEROL, answered by our medical review team.
VOSEVI is a Direct-Acting Antiviral Combination that works by VOSEVI (sofosbuvir, velpatasvir, and voxilaprevir) is a fixed-dose combination of a nucleotide analog NS5B polymerase inhibitor (sofosbuvir), an NS5A inhibitor (velpatasvir), and a NS3/4A protease inhibitor (voxilaprevir). The combination inhibits hepatitis C virus replication by targeting multiple viral proteins.. ATROPINE AND DEMEROL is a Opioid Analgesic Combination that works by Atropine is an antimuscarinic agent that competitively blocks acetylcholine at muscarinic receptors, reducing secretions and gastrointestinal motility. Meperidine (Demerol) is an opioid agonist that binds to mu-opioid receptors in the CNS, altering pain perception and producing analgesia.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between VOSEVI and ATROPINE AND DEMEROL 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 VOSEVI is: One tablet (sofosbuvir 400 mg/velpatasvir 100 mg/voxilaprevir 100 mg) orally once daily with food for 8 weeks.. The standard adult dose of ATROPINE AND DEMEROL is: Atropine 0.4 mg and Demerol (meperidine) 50-100 mg intramuscularly as preanesthetic medication 30-60 minutes before procedure.. 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 VOSEVI and ATROPINE AND DEMEROL 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. VOSEVI is classified as Category C. VOSEVI is contraindicated in pregnancy due to risk of fetal harm. No adequate human data; animal studies show developmental toxicity at clinically relevant exposures. Use effective. ATROPINE AND DEMEROL is classified as Category C. Atropine: FDA Pregnancy Category C. Crosses placenta; may cause fetal tachycardia. Demerol (meperidine): FDA Pregnancy Category C. First trimester: limited human data; animal studi. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.