PRECAUTIONS Patients with impaired renal or hepatic function The safety and pharmacokinetics of Carisoprodol and Aspirin in patients with renal or hepatic impairment have not been evaluated. Carisoprodol: Since carisoprodol is excreted by the kidney and is metabolized in the liver, caution should be exercised if carisoprodol is administered to patients with impaired renal or hepatic function. Carisoprodol is dialyzable by hemodialysis and peritoneal dialysis. Seizures There have been postmarketing reports of seizures in patients who received carisoprodol. Most of these cases have occurred in the setting of multiple drug overdoses (including drugs of abuse, illegal drugs, and alcohol) (see OVERDOSAGE ). Aspirin: Adverse Reactions In addition to serious gastrointestinal adverse reactions, the use of aspirin is also associated with gastritis, gastrointestinal erosions, abdominal pain, heartburn, vomiting, and nausea (see WARNINGS, Serious Gastrointestinal Adverse Reactions ). Information for Patients: Patients should be advised to contact their health care provider if they experience any adverse reactions to Carisoprodol and Aspirin Tablets. Carisoprodol: Patients should be advised that carisoprodol may cause drowsiness and/or dizziness, and has been associated with motor vehicle accidents. Patients should be advised to avoid taking carisoprodol before engaging in potentially hazardous activities such as driving a motor vehicle or operating machinery (see WARNINGS, Sedation ). Patients should be advised to avoid alcoholic beverages while taking carisoprodol and to check with their doctor before taking other CNS depressants such as benzodiazepines, opioids, tricyclic antidepressants, sedating antihistamines, or other sedatives (see WARNINGS, Sedation ). Patients should be advised that treatment with carisoprodol should be limited to acute use (up to two or three weeks) for the relief of acute, musculoskeletal discomfort. In the post-marketing experience with carisoprodol, cases of dependence, withdrawal, and abuse have been reported with prolonged use. If the musculoskeletal symptoms still persist, patients should contact their healthcare provider for further evaluation. Aspirin: Patients should be warned that aspirin can cause epigastric discomfort, gastric and duodenal ulcers, and serious GI adverse reactions, such as bleeding, perforation, and/or obstruction of the stomach or intestines, which may result in hospitalization and death. Although serious GI bleeding can occur without warning symptoms (e.g., hematemesis, melena, hematochezia), patients should be alert for these symptoms and should seek urgent medical care if any of these indicative symptoms occur (see WARNINGS, Serious Gastrointestinal Adverse Reactions ). In addition, patients should be alert for symptoms of ulcers (e.g., night time epigastric discomfort, vomiting, weight loss) and should seek medical attention if these symptoms occur. Patients who consume three or more alcoholic drinks every day should be counseled about the GI bleeding risks involved with the use of aspirin with alcohol. Patients should be informed of the symptoms of an anaphylactoid reaction or anaphylaxis (e.g., hives, difficulty breathing, swelling of face or throat). If these symptoms occur, patients should be instructed to seek immediate emergency help. Drug Interactions Carisoprodol: The sedative effect of carisoprodol and other CNS depressants (e.g., alcohol, benzodiazepines, opioids, tricyclic antidepressants) may be additive. Therefore, caution should be exercised with patients who take more than one of these CNS depressants simultaneously. Concomitant use of carisoprodol and meprobamate, a metabolite of carisoprodol, is not recommended (see WARNINGS, Sedation). Carisoprodol is metabolized in the liver by CYP2C19 to form meprobamate (see CLINICAL PHARMACOLOGY ). Co-administration of CYP2C19 inhibitors, such as omeprazole or fluvoxamine, with carisoprodol could result in increased exposure of carisoprodol and decreased exposure of meprobamate. Co-administration of CYP2C19 inducers, such as rifampin or St. John’s Wort, with carisoprodol could result in decreased exposure of carisoprodol and increased exposure of meprobamate. Low dose aspirin also showed an induction effect of CYP2C19. The full pharmacological impact of these potential alterations of exposures in terms of either efficacy or safety of carisoprodol is unknown. Aspirin: Clinically important interactions may occur when certain drugs or alcohol are administered concomitantly with aspirin. Alcohol: Concomitant use of aspirin with ≥ 3 alcoholic drinks may increase the risk of GI bleeding (see WARNINGS, Serious Gastrointestinal Adverse Reactions ). Anticoagulants: Concomitant use of aspirin and anticoagulants (e.g., heparin, warfarin, clopidogrel) increase the risk of GI bleeding (see WARNINGS, Serious Gastrointestinal Adverse Reactions ). Additionally, aspirin can displace warfarin from protein binding sites, leading to prolongation of the international normalized ratio (INR). Antihypertensives: The concomitant administration of aspirin with angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), beta-blockers, and diuretics may diminish the hypotensive effects of these anti-hypertensive products due to aspirin’s inhibition of renal prostaglandins, which may lead to decreased renal blood flow and increased sodium and fluid retention. Concomitant use of aspirin and acetazolamide can lead to high serum concentrations of acetazolamide due to competition at the renal tubule for secretion. Corticosteroids: Concomitant administration of aspirin and corticosteroids may decrease salicylate plasma levels. Methotrexate: Aspirin may enhance the toxicity of methotrexate due to displacement of methotrexate from its plasma protein binding sites and/or reduction of the renal clearance of methotrexate. Nonsteroidal anti-inflammatory drugs (NSAIDs): The concurrent use of aspirin with selective and nonselective NSAIDs increases the risk of serious GI adverse reactions (see WARNINGS, Serious Gastrointestinal Adverse Reactions ). Oral Hypoglycemics Agents: Aspirin may increase the serum glucose-lowering action of insulin and sulfonylureas leading to hypoglycemia. Products that effect urinary pH: Ammonium chloride and other drugs that acidify the urine can elevate plasma salicylate concentrations. In contrast, antacids, by alkalinizing the urine, may decrease plasma salicylate concentrations. Uricosuric Agents: Salicylates antagonize the uricosuric action of probenecid and sulfinpyrazone. Carcinogenesis, Mutagenesis, Impairment of Fertility: No long-term studies of carcinogens have been done with Carisoprodol and Aspirin Carisoprodol: Long term studies in animals have not been performed to evaluate the carcinogenic potential of carisoprodol. Carisoprodol was not formally evaluated for genotoxicity. In published studies, carisoprodol was mutagenic in the in vitro mouse lymphoma cell assay in the absence of metabolizing enzymes, but was not mutagenic in the presence of metabolizing enzymes. Carisoprodol was clastogenic in the in vitro chromosomal aberration assay using Chinese hamster ovary cells with or without the presence of metabolizing enzymes. Other types of genotoxic tests resulted in negative findings. Carisoprodol was not mutagenic in the Ames reverse mutation assay using S. typhimurium strains with or without metabolizing enzymes, and was not clastogenic in an in vivo mouse micronucleus assay of circulating blood cells. Carisoprodol was not formally evaluated for effects on fertility. Published reproductive studies of carisoprodol in mice found no alteration in fertility although an alteration in reproductive cycles characterized by a greater time spent in estrus was observed at a carisoprodol dose of 1200 mg/kg/day. In a 13-week toxicology study that did not determine fertility, mouse testes weight and sperm motility were reduced at a dose of 1200 mg/kg/day. In both studies, the no effect level was 750 mg/kg/day, corresponding to approximately 2.6 times the human equivalent dosage of 350 mg four times a day, based on a body surface area comparison. The significance of these findings for human fertility is not known. Aspirin: Administration of aspirin for 68 weeks in the feed of rats was not carcinogenic. In the Ames Salmonella assay, aspirin was not mutagenic; however, aspirin did induce chromosome aberrations in cultured human fibroblasts. Aspirin has been shown to inhibit ovulation in rats (see Pregnancy). Pregnancy: Pregnancy Category D. It is not known whether Carisoprodol and Aspirin can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Adequate animal reproduction studies have not been conducted with Carisoprodol and Aspirin. Carisoprodol and Aspirin should be given to a pregnant woman only if clearly needed. Carisoprodol: There are no data on the use of carisoprodol during human pregnancy. Animal studies indicate that carisoprodol crosses the placenta and results in adverse effects on fetal growth and postnatal survival. The primary metabolite of carisoprodol, meprobamate, is an approved anxiolyic. Retrospective, post-marketing studies do not show a consistent association between maternal use of meprobamate and an increased risk for particular congenital malformations. Teratogenic effects: Animal studies have not adequately evaluated the teratogenic effects of carisoprodol. There was no increase in the incidence of congenital malformations noted in the reproductive studies in rats, rabbits, and mice treated with meprobamate. Retrospective, post-marketing studies of meprobamate during human pregnancy were equivocal for demonstrating an increased risk of congenital malformations following the first trimester exposure. Across studies that indicated an increased risk, the types of malformations were inconsistent. Nonteratogenic effects: In animal studies, carisoprodol reduced fetal weights, postnatal weight gain, and postnatal survival at maternal doses equivalent to 1 to 1.5 times the human dose (based on a body surface area comparison). Rats exposed to meprobamate in-utero showed behavioral alterations that persisted into adulthood. For children exposed to meprobamate in-utero, one study found no adverse effects on mental or motor development or IQ scores. Carisoprodol should be used during pregnancy only if the potential benefit justifies the risk to the fetus. Aspirin: Teratogenic effects: Prior to 30 weeks gestation, aspirin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Starting at 30 weeks gestation, aspirin should be avoided by pregnant women as premature closure of the fetal ductus arteriosus which may result in fetal pulmonary hypertension and fetal death. Salicylate products have also been associated with alterations in maternal and neonatal hemostasis mechanisms, decreased birth weight, increased incidence of intracranial hemorrhage in premature infants, stillbirths, and neonatal death. Studies in rodents have show salicylates to be teratogenic when given in early gestation, and embryocidal when given in later gestation in doses considerably greater than usual therapeutic doses in humans.