The Complete Demerol (Meperidine) Buying Guide
- What Demerol is and how it is classified
- How it works (mu-opioid receptor agonist)
- FDA-approved uses and controlled substance schedule
- Why Demerol has fallen out of favor
- Normeperidine toxicity and seizure risk
- Drug interactions and contraindications
- Precautions and when to contact a clinician
- Personalized medical advice or treatment recommendations
- Specific dosing for your individual condition
- Information about purchasing medications
- Alternatives to prescribed treatments (consult your provider)
On This Page
What Is Demerol?
Demerol is the brand name for meperidine hydrochloride, a synthetic opioid analgesic used for the management of moderate to severe pain. It was first synthesized in 1939 and approved by the FDA for medical use.
Demerol has been used in various clinical settings, including postoperative pain, labor pain, and acute pain management. It is available in oral (tablets, oral solution) and injectable (intramuscular, intravenous, subcutaneous) formulations.
Demerol is designated as a Schedule II controlled substance under the federal Controlled Substances Act, indicating high potential for abuse which may lead to severe psychological or physical dependence.
How Demerol Works
Meperidine works primarily as an agonist at the mu-opioid receptor in the central nervous system. Activation of this receptor produces analgesia (pain relief), euphoria, sedation, and respiratory depression.
Unlike most opioids, meperidine also has local anesthetic properties and weak serotonin reuptake inhibition. Its unique pharmacological profile gives it some advantages in specific clinical situations but also contributes to its toxicity.
Meperidine is metabolized in the liver to normeperidine, an active metabolite that is neurotoxic and has a longer half-life (15-30 hours) than the parent compound (3-4 hours). Accumulation of normeperidine is responsible for many of the adverse effects associated with meperidine use.
FDA Schedule & Classification
| Drug Name | Demerol (meperidine hydrochloride) |
|---|---|
| Drug Class | Opioid analgesic |
| DEA Schedule | Schedule II (C-II) |
| Controlled Substance Act | High potential for abuse which may lead to severe psychological or physical dependence |
| Prescription Required | Yes |
| FDA Approval | 1940s |
| Availability | Generic and brand-name (Demerol) |
FDA-Approved Uses
Demerol is FDA-approved for the management of moderate to severe pain. However, its use has significantly declined due to safety concerns:
- Postoperative pain: Historically used for acute postoperative pain management
- Labor pain: Was commonly used during labor; now largely replaced by other analgesics
- Acute pain: Used for short-term management of severe pain episodes
Major medical organizations, including the American Pain Society and the Joint Commission, have recommended against the routine use of meperidine for pain management. Most hospitals have removed meperidine from their formularies or restricted its use to very specific clinical situations (such as rigors associated with amphotericin B therapy).
Dosage Forms & Strengths
Oral Formulations
| Form | Strength | Typical Dosing |
|---|---|---|
| Tablet | 50 mg, 100 mg | 50-150 mg every 3-4 hours as needed |
| Oral solution | 50 mg/5 mL | 50-150 mg every 3-4 hours as needed |
Injectable Formulations
| Route | Strength | Typical Dosing |
|---|---|---|
| Intramuscular (IM) | 50 mg/mL, 75 mg/mL, 100 mg/mL | 50-150 mg every 3-4 hours |
| Intravenous (IV) | 10 mg/mL | Starting dose 10-15 mg; titrate to effect |
| Subcutaneous (SC) | 50 mg/mL | 50-150 mg every 3-4 hours |
Maximum daily dose: Generally should not exceed 600 mg/day for outpatient use. Due to normeperidine accumulation, shorter courses are preferred.
Elderly patients and those with renal impairment require significant dose reductions due to increased risk of normeperidine accumulation.
Why Demerol Has Fallen Out of Favor
- Normeperidine toxicity: The active metabolite accumulates with repeated dosing and can cause seizures, myoclonus, and hyperexcitability
- Seizure risk: Normeperidine lowers the seizure threshold, particularly at high doses or in patients with renal impairment
- Shorter duration of analgesia: Meperidine has a shorter analgesic duration than many other opioids
- Serotonin syndrome risk: Meperidine's weak serotonin reuptake inhibition can contribute to serotonin syndrome when combined with other serotonergic drugs
- Histamine release: Can cause hypotension, bronchospasm, and pruritus
- No advantage over morphine: Studies have shown no significant advantage of meperidine over morphine for most pain conditions
The accumulation of normeperidine is particularly problematic because:
- Its half-life (15-30 hours) is much longer than meperidine (3-4 hours)
- It builds up with repeated dosing, especially with frequent dosing schedules
- It has no analgesic properties — only neurotoxic effects
- Renal impairment significantly increases its accumulation
- Seizures from normeperidine toxicity can occur without warning
Side Effects
Common Side Effects
- Drowsiness and sedation
- Dizziness and lightheadedness
- Nausea and vomiting
- Constipation
- Dry mouth
- Headache
- Sweating
- Orthostatic hypotension
Serious Side Effects
- Seizures — from normeperidine accumulation; can occur without warning
- Myoclonus — involuntary muscle jerking, an early sign of neurotoxicity
- Hyperexcitability — tremors, irritability, twitching
- Severe respiratory depression — especially with high doses or when combined with other CNS depressants
- Serotonin syndrome — agitation, confusion, rapid heart rate, high blood pressure, muscle rigidity (when combined with serotonergic drugs)
- Severe allergic reaction (anaphylaxis)
- QT prolongation — cardiac rhythm changes
- Histamine release reactions — hypotension, bronchospasm, flushing
Drug Interactions
Major Interactions (Avoid or Use Extreme Caution)
- MAO inhibitors — can cause serotonin syndrome or excitatory reactions (excitability, hypertension, hyperpyrexia); contraindicated
- Serotonergic drugs (SSRIs, SNRIs, triptans, tramadol) — risk of serotonin syndrome
- Other CNS depressants (benzodiazepines, alcohol, other opioids) — additive respiratory depression
- Drugs that lower seizure threshold — additive seizure risk with normeperidine
Moderate Interactions (Monitor Closely)
- CYP3A4 and CYP2D6 inhibitors — may increase meperidine levels
- CYP inducers (rifampin) — may decrease meperidine effectiveness
- Anticholinergic drugs — additive constipation and urinary retention
- Cardiotoxic drugs — additive QT prolongation risk
Precautions & Warnings
- Pregnancy: Meperidine crosses the placenta. Neonatal withdrawal syndrome can occur. Use during labor may cause respiratory depression in the newborn.
- Breastfeeding: Excreted in breast milk. Use is generally not recommended.
- Renal impairment: Significantly increases risk of normeperidine accumulation and seizures. Dose reduction required; many clinicians avoid meperidine in renal impairment.
- Liver disease: May require dose adjustment due to altered metabolism.
- History of seizures: Normeperidine can lower seizure threshold; use with extreme caution or avoid.
- Head injury and increased intracranial pressure: Meperidine may increase intracranial pressure.
- Driving and machinery: Causes significant drowsiness and impairs coordination.
- Duration of use: Limit to short-term use (generally less than 48 hours) to minimize normeperidine accumulation.
When to Contact a Clinician
Reach out to your healthcare provider if you experience any of the following:
- You are having muscle jerks, twitching, or tremors (early signs of neurotoxicity)
- You are experiencing increased anxiety, irritability, or confusion
- Pain is not adequately controlled
- You notice new or unexpected side effects
- You are having difficulty urinating
- You are experiencing persistent nausea or vomiting
- You have questions about your medication
- You want to stop the medication — consult your provider for guidance
Seek emergency care immediately if you experience seizures, difficulty breathing, severe allergic reaction, or loss of consciousness.
Cited Sources
- FDA — Demerol (Meperidine) Prescribing Information (AccessData, FDA)
- MedlinePlus — Meperidine (National Library of Medicine)
- StatPearls — Meperidine (National Library of Medicine)
- DEA — Controlled Substance Schedules
- PubChem — Meperidine (National Institutes of Health)