Comparative Pharmacology
Head-to-head clinical analysis: MEPERIDINE AND ATROPINE SULFATE versus WESTADONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: MEPERIDINE AND ATROPINE SULFATE versus WESTADONE.
MEPERIDINE AND ATROPINE SULFATE vs WESTADONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Meperidine is a synthetic opioid agonist primarily at mu-opioid receptors, producing analgesia; atropine is a competitive antagonist of muscarinic acetylcholine receptors, reducing gastrointestinal motility and secretions.
Mu-opioid receptor agonist; also acts as an NMDA receptor antagonist and inhibits serotonin and norepinephrine reuptake.
1-2 mL (meperidine 50 mg/mL + atropine 0.4 mg/mL) IM or IV push (over 2-3 minutes) every 3-4 hours as needed.
Oral: 2.5-10 mg every 4-6 hours as needed for pain; maximum 40 mg per day.
None Documented
None Documented
Meperidine: Terminal half-life 3-4 hours (normal renal function), prolonged in hepatic disease (up to 7-10 hours) and renal impairment (normeperidine accumulates). Atropine: Terminal half-life 2-4 hours.
Terminal elimination half-life: 15-60 hours (mean ~24 hours). Clinical context: Prolonged half-life supports once-daily dosing in opioid maintenance; accumulation occurs with repeated dosing due to long half-life.
Meperidine: Renal excretion of unchanged drug (~5-10%) and metabolites, primarily normeperidine (active), with <5% biliary/fecal. Atropine: Renal excretion (~30-50% unchanged), remainder as metabolites, minimal biliary/fecal.
Primarily renal (40-50% as unchanged methadone and its metabolites, 15-20% as metadone-N-oxide), biliary/fecal (5-10%).
Category D/X
Category C
Opioid Agonist
Opioid Agonist