SOMA COMPOUND
Clinical safety rating
cautionComprehensive clinical and safety monograph for SOMA COMPOUND (SOMA COMPOUND).
Carisoprodol is a centrally acting muscle relaxant that acts through its metabolite meprobamate, which modulates GABA-A receptors and inhibits neuronal activity in the reticular formation and spinal cord. Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that irreversibly inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis and providing analgesic, anti-inflammatory, and antipyretic effects.
| Metabolism | Carisoprodol is metabolized by CYP2C19 to meprobamate (active metabolite); aspirin is hydrolyzed to salicylic acid via esterases in the liver and plasma. |
| Excretion | Carisoprodol and its active metabolite meprobamate are primarily excreted renally. Approximately 60% of a dose is eliminated as unchanged carisoprodol and meprobamate in urine, with the remainder as various hydroxylated metabolites. Less than 1% is eliminated in feces. Meprobamate undergoes hepatic metabolism, and about 10-20% is excreted unchanged in urine. |
| Half-life | Carisoprodol: approximately 2-4 hours in adults with normal renal function. Meprobamate: approximately 10-12 hours. The prolonged half-life of meprobamate contributes to accumulation with repeated dosing, especially in elderly or renally impaired patients, leading to increased risk of sedation and dependence. |
| Protein binding | Carisoprodol: approximately 60% bound to plasma proteins, primarily albumin. Meprobamate: approximately 15-25% bound to plasma proteins. |
| Volume of Distribution | Carisoprodol: Vd approximately 0.5-1.0 L/kg, indicating distribution into total body water and some tissue binding. Meprobamate: Vd about 0.7 L/kg. |
| Bioavailability | Oral: Carisoprodol is well absorbed with bioavailability >90%. The absorption rate may be slightly reduced with food, but extent is not significantly affected. |
| Onset of Action | Oral: Onset of muscle relaxant effect typically occurs within 30 minutes, with peak plasma concentrations reached at 1-2 hours post-dose. |
| Duration of Action | Oral: Clinical effects last approximately 4-6 hours for carisoprodol. However, due to the long half-life of meprobamate, sedation and residual effects may persist longer. Clinical use is limited to short-term (up to 2-3 weeks) due to risk of dependence. |
| Molecular Weight | 260.33 Da (carisoprodol); 180.16 Da (aspirin) |
1-2 tablets (carisoprodol 200mg/aspirin 325mg) orally 4 times daily.
| Dosage form | TABLET |
| Renal impairment | CrCl <30 mL/min: avoid use due to aspirin component; CrCl 30-50 mL/min: reduce dose or extend interval; monitor for carisoprodol accumulation. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use. |
| Pediatric use | Not recommended for children under 12 years; safety and efficacy not established. |
| Geriatric use | Initiate at lowest dose (1 tablet); avoid use in patients with CrCl <30 mL/min; monitor for CNS depression and bleeding risk. |
| 1st trimester | Avoid; risk of fetal malformations (neural tube defects) associated with valproate component. |
| 2nd trimester | Avoid; risk of teratogenicity and neonatal hemorrhage. |
| 3rd trimester | Avoid; risk of neonatal bleeding, hepatotoxicity, and withdrawal symptoms. |
Clinical note
Comprehensive clinical and safety monograph for SOMA COMPOUND (SOMA COMPOUND).
| Placental transfer | Both components cross the placenta. Aspirin (especially at high doses) and carisoprodol (via passive diffusion) reach fetal circulation. Valproate (if present) also crosses. |
| Breastfeeding | Both carisoprodol and aspirin are excreted into breast milk. Potential for infant sedation, bleeding (aspirin effect), and Reye's syndrome. Use caution; avoid in nursing mothers due to risks. |
| Lactation Rating | L4 - Possibly Hazardous |
| Teratogenic Risk | Carisoprodol (Soma) is FDA Pregnancy Category C. Inadequate human data; animal studies suggest risk. Not recommended in first trimester due to potential teratogenicity. Aspirin component (if present in compound) is associated with increased risk of neural tube defects and fetal hemorrhage if used in third trimester. Avoid use during pregnancy unless benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal CNS effects (sedation, dizziness). No specific fetal monitoring recommended except standard obstetric care. If used near term, monitor newborn for signs of respiratory depression or withdrawal. |
| Fertility Effects | No specific human data on fertility effects. Animal studies have not shown significant impairment. Theoretical risk due to CNS depressant effects on hormonal regulation. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Concurrent use of valproate in women of childbearing potential unless pregnancy prevention measures are in placeHistory of hypersensitivity to carisoprodol or aspirinActive peptic ulcer diseaseBleeding disorders (e.g., hemophilia)Severe hepatic impairmentSevere renal impairment
| Precautions | Dependence and withdrawal: Carisoprodol can cause dependence, abuse, and withdrawal symptoms after prolonged use, Sedation: May impair mental or physical abilities; caution with driving or operating machinery, Bleeding risk: Aspirin component increases risk of bleeding, especially with alcohol, anticoagulants, or existing bleeding disorders, Hypersensitivity: Allergic reactions including anaphylaxis can occur |
| Food/Dietary | Avoid alcohol. Aspirin may cause gastrointestinal irritation; take with food or a full glass of water to reduce risk. Avoid high-dose vitamin C or acidic foods that may increase aspirin absorption and toxicity. |
| Clinical Pearls | Soma Compound contains carisoprodol (a centrally acting muscle relaxant) and aspirin (an NSAID). Carisoprodol is metabolized to meprobamate, a controlled substance with abuse potential. Avoid in patients with a history of substance abuse, porphyria, or G6PD deficiency. Monitor for signs of CNS depression, especially when combined with alcohol or other sedatives. Aspirin increases bleeding risk; avoid in patients with bleeding disorders or those on anticoagulants. Do not use in children or adolescents with viral infections due to risk of Reye's syndrome. |
| Patient Advice | Take exactly as prescribed; do not increase dose or frequency. · Do not drive or operate heavy machinery until you know how this medication affects you. · Avoid alcohol and other CNS depressants while taking this medication. · Report any signs of bleeding (bruising, black stools, blood in urine) or allergic reactions (rash, swelling, difficulty breathing). · Do not use in children or teenagers with chickenpox or flu symptoms due to risk of Reye's syndrome. · This medication may be habit-forming; do not stop abruptly without consulting your doctor. · Store at room temperature away from moisture and heat. |
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