EQUAGESIC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EQUAGESIC (EQUAGESIC).
Equagesic is a combination of aspirin and meprobamate. Aspirin irreversibly inhibits cyclooxygenase-1 (COX-1) and COX-2, reducing prostaglandin synthesis. Meprobamate potentiates GABA-A receptor activity, producing anxiolytic and sedative effects.
| Metabolism | Aspirin is hydrolyzed to salicylic acid by esterases in the liver and gut. Meprobamate is metabolized by CYP2C19 and other hepatic enzymes, primarily to inactive metabolites. |
| Excretion | Meprobamate: renal (10% as unchanged drug, 80-90% as hydroxylated metabolites); Aspirin: renal (dose-dependent, 50-80% as salicyluric acid, 10% as unchanged salicylate at acidic pH). |
| Half-life | Meprobamate: 10-12 hours in healthy adults, prolonged in liver disease; Aspirin: low doses 2-3 hours, anti-inflammatory doses 15-30 hours (saturable elimination). |
| Protein binding | Meprobamate: 20-30% to albumin; Aspirin: 80-90% to albumin (saturable, decreased in hypoalbuminemia). |
| Volume of Distribution | Meprobamate: 0.75-1.0 L/kg; Aspirin: 0.1-0.2 L/kg (salicylate), increased in inflammation. |
| Bioavailability | Meprobamate: oral >90%; Aspirin: oral 80-100% (first-pass hydrolysis to salicylate). |
| Onset of Action | Meprobamate: oral 30-60 minutes; Aspirin: oral analgesia 30 minutes, anti-inflammatory days to weeks. |
| Duration of Action | Meprobamate: 6-8 hours; Aspirin: analgesic 3-4 hours, anti-inflammatory sustained with chronic dosing. |
Adults: 1 tablet (200 mg meprobamate, 25 mg ethoheptazine citrate, 325 mg aspirin) orally 3 or 4 times daily.
| Dosage form | TABLET |
| Renal impairment | CrCl 10-50 mL/min: Not recommended due to aspirin and meprobamate accumulation. CrCl <10 mL/min: Contraindicated. |
| Liver impairment | Child-Pugh Class B or C: Contraindicated due to hepatotoxicity risk. Consider avoiding in mild impairment. |
| Pediatric use | Not recommended for pediatric use due to salicylate and meprobamate risks. |
| Geriatric use | Initiate at lower doses (e.g., 1 tablet twice daily) with monitoring for CNS depression, bleeding, and renal function. Avoid if CrCl <50 mL/min. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for EQUAGESIC (EQUAGESIC).
| Breastfeeding | Both aspirin and meprobamate are excreted in breast milk. Aspirin M/P ratio is approximately 0.6; meprobamate M/P ratio is approximately 2-4. Potential for infant salicylate toxicity (Reye syndrome risk) and sedation. Contraindicated during breastfeeding unless essential, and if used, monitor infant for bleeding, vomiting, and drowsiness. Avoid high-dose or prolonged use. |
| Teratogenic Risk | EQUAGESIC (aspirin/meprobamate) is contraindicated in pregnancy, especially during the third trimester, due to aspirin-induced premature closure of the ductus arteriosus, oligohydramnios, and increased risk of fetal hemorrhage; meprobamate is associated with congenital malformations (e.g., cleft lip/palate) when used in the first trimester. High doses near term increase neonatal bleeding risk. |
■ FDA Black Box Warning
Warning: Risk of serious cardiovascular events and gastrointestinal bleeding with aspirin; potential for dependence and withdrawal with meprobamate.
| Serious Effects |
Hypersensitivity to aspirin, meprobamate, or NSAIDs; active peptic ulcer or GI bleeding; severe hepatic impairment; porphyria; concurrent use of MAOIs; pregnancy (especially third trimester for aspirin); children with viral illness (Reye's syndrome risk).
| Precautions | Cardiovascular and GI bleeding risks with aspirin; dependence, withdrawal seizures, and sedation with meprobamate; avoid abrupt discontinuation; use caution in patients with peptic ulcer disease, bleeding disorders, hepatic impairment, or history of substance abuse. |
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| Fetal Monitoring | Monitor maternal bleeding time, platelet function, and signs of gastrointestinal bleeding. In fetus/newborn, monitor for premature ductus arteriosus closure via fetal echocardiography, oligohydramnios via ultrasound (third trimester), and neonatal bleeding (e.g., cephalohematoma). Monitor for congenital anomalies with first-trimester exposure. |
| Fertility Effects | Aspirin may impair fertility by inhibiting prostaglandin synthesis, affecting ovulation and implantation; meprobamate may cause menstrual irregularities due to CNS effects. EQUAGESIC use is associated with reduced fertility in women of reproductive age. |