Drug Interactions between fentanyl / ropivacaine and Margesic

Using fentaNYL together with other medications that cause central nervous system depression such as butalbital can lead to serious side effects including respiratory distress, coma, and even death. Additionally, butalbital may reduce the blood levels of fentaNYL in some cases, which may make the medication less effective in treating your condition. If you have been receiving treatment with fentaNYL, adding butalbital may cause you to experience unpleasant withdrawal symptoms such as watery eyes, runny nose, sneezing, yawning, excessive sweating, goose bumps, fever, chills, flushing, restlessness, irritability, anxiety, depression, pupil dilation, tremor, rapid heart beat, body aches, involuntary twitching and kicking, abdominal cramping, loss of appetite, nausea, vomiting, diarrhea, and weight loss. On the other hand, if you have been receiving both medications, discontinuing butalbital may increase the blood levels of fentaNYL, which could lead to an overdose. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Do not drink alcohol or self-medicate with these medications without your doctor's approval, and do not exceed the doses or frequency and duration of use prescribed by your doctor. Also, you should avoid driving or operating hazardous machinery until you know how these medications affect you. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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Using acetaminophen together with butalbital may alter the effects of acetaminophen and cause serious side effects that may affect your liver. Call your doctor immediately if you experience a fever, chills, joint pain or swelling, excessive tiredness or weakness, unusual bleeding or bruising, skin rash or itching, loss of appetite, nausea, vomiting, or yellowing of the skin or the whites of your eyes. If your doctor does prescribe these medications together, you may need a dose adjustment or special tests to safely take both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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Consumer information for this interaction is not currently available.

MONITOR: Coadministration of local anesthetics with other oxidizing agents that can also induce methemoglobinemia such as antimalarials (e.g., chloroquine, quinine), nitrates and nitrites, sulfonamides, aminosalicylic acid, dimethyl sulfoxide (DMSO), metoclopramide, nitrofurantoin, phenazopyridine, phenobarbital, and phenytoin may increase the risk. Additional risk factors include very young age (e.g., infants less than 6 months), cardiac or pulmonary disease, genetic predisposition, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Data surrounding the incidence of methemoglobinemia are agent-specific and, in many instances, have primarily been reported in case reports and/or in overdose situations.

MANAGEMENT: Monitoring for signs and symptoms of methemoglobinemia is recommended if local anesthetics must be used with other methemoglobin-inducing agents. Signs and symptoms of methemoglobinemia may occur immediately or hours after drug exposure. Patients or their caregivers should be advised to seek medical attention if they notice signs and symptoms of methemoglobinemia (e.g., cyanotic skin discoloration, abnormal blood coloration, nausea, headache, dizziness, lightheadedness, lethargy, fatigue, dyspnea, tachypnea, tachycardia, palpitation, anxiety, and confusion). In severe cases, patients may progress to central nervous system depression, stupor, seizures, acidosis, cardiac arrhythmias, syncope, shock, coma, and death. Methemoglobinemia should be considered if central cyanosis is unresponsive to oxygen. Calculated oxygen saturation and pulse oximetry are generally not accurate in the setting of methemoglobinemia. The diagnosis can be confirmed by an elevated methemoglobin level of at least 10% using co-oximetry. Methemoglobin concentrations greater than 10% of total hemoglobin will typically cause cyanosis, and levels over 70% are frequently fatal. However, symptom severity is not always related to methemoglobin levels. Experts suggest that treatment of methemoglobinemia varies from supplemental oxygen and symptom support to the administration of methylene blue, depending on severity of symptoms and/or the presence of G6PD deficiency. Institutional guidelines and/or individual product labeling should be consulted for further guidance.

Information for this minor interaction is available on the professional version.