Meperidine
DEMEROL
Pronunciation: me-PER-i-deen
“Meeper Demoralized”
What it isMu-opioid agonist; acute pain and postoperative shivering.
Why this oneIts unusually strong anti-shivering effect is the main niche that survives its abandonment as a routine analgesic.
What limits it⚑ Normeperidine accumulates in renal disease and can provoke seizures; avoid repeated dosing. MAO inhibitors can trigger serotonin syndrome.
FDA-approved for
- pain (~1942)
Off-label
- postoperative shivering
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Acute pain | Adults | 50–150 mg PO q3–4h PRN | Lowest effective dose | ≤600 mg/day (discontinue if inadequate) |
| Acute pain | Pediatric | 1.1–1.8 mg/kg PO q3–4h PRN (up to adult dose) | Lowest effective dose | Up to adult dose |
Renal Use with caution; titrate slowly (meperidine/normeperidine accumulation)
Hepatic Use with caution; titrate slowly (meperidine/normeperidine accumulation)
Dose q3–4h as needed
Instructions
- Reduce dose 25–50% when given with phenothiazines or other tranquilizers
- Oral solution: prescribe/measure in both mg and mL to avoid dosing errors; use a graduated device
- Do not abruptly discontinue in physically dependent patients; taper by ≤10–25% of daily dose every 2–4 weeks
Available strengths
- tab 50, 100 mg
- sol 50 mg/5 mL
- inj 10, 25, 50, 75, 100 mg/mL
Contraindications
- Significant respiratory depression
- Acute or severe bronchial asthma in an unmonitored setting or absent resuscitative equipment
- Known or suspected GI obstruction, including paralytic ileus
- MAOIs (concurrently or within 14 days) due to risk of coma, severe respiratory depression, cyanosis, and hypotension
Cautions
- Serotonin syndrome with concomitant serotonergic drugs
- Opioid-induced hyperalgesia and allodynia
- Life-threatening respiratory depression, especially at initiation/titration and in elderly/debilitated/pulmonary disease
- Adrenal insufficiency
- Severe hypotension; avoid in circulatory shock
- Increased intracranial pressure/head injury; avoid in impaired consciousness or coma
- Normeperidine accumulation may cause CNS excitation/seizures
Adverse reactions
- Lightheadedness
- Dizziness
- Sedation
- Nausea
- Vomiting
- Sweating
Pregnancy Insufficient data; prolonged use may cause neonatal opioid withdrawal; not recommended during/immediately before labor
Lactation Meperidine appears in human milk; monitor breastfed infant for excess sedation and respiratory depression
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 50 mg | tab | per unit | not offered | |
| 100 mg | tab | per unit | not offered | |
| 50 mg/5 mL | sol | per unit | $0.16/mL | not offered |
| 10 mg/mL | inj | per unit | not offered | |
| 25 mg/mL | inj | per unit | not offered | |
| 50 mg/mL | inj | per unit | not offered | |
| 75 mg/mL | inj | per unit | not offered | |
| 100 mg/mL | inj | per unit | not offered |
Generic entry1984
⚠ BOXED WARNINGS
- Addiction, abuse and misuse
- Life-threatening respiratory depression
- Risk from concomitant use with benzodiazepines
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityRespiratory depression, dependence and overdose; risk rises sharply with sedatives or impaired clearance.
Serotonin and MAOI
Provisional washout figures
Elevating mechanismSRI
Non-elevating actionNone recorded
Exposure dependenceTherapeutic exposure; severe toxicity requires meaningful MAO-A inhibition
Washout BEFORE an MAOI14 days
Evidence confidenceHigh
InterpretationOpioid with clinically significant SRI activity; dangerous with meaningful MAO-A inhibition. A second SRI generally represents therapeutic duplication/additive adverse effects, not the classic life-threatening interaction.
Active metabolites
Open Meperidine in the interactive console ↗
Memory aids: interaction avatars
