Drug Interactions between acetaminophen / dextromethorphan / diphenhydramine / guaifenesin / phenylephrine and Mylanta

Citrate, or citric acid, can increase the absorption of aluminum hydroxide. This may lead to elevated blood levels of aluminum, particularly in individuals with reduced kidney function, since aluminum is primarily eliminated by the kidneys. Excess aluminum may deposit and cause problems in various tissues including bone, brain, heart, liver, muscles, and spleen. Over time, weak bones, bone pain, fractures, skeletal deformity, brain disorders, and anemia may develop. Talk to your doctor before using aluminum hydroxide if you have kidney impairment or are on hemodialysis. You should avoid or limit the consumption of citrate-containing foods and beverages (e.G., soft drinks, citrus fruits, fruit juices) during treatment with aluminum hydroxide. Be aware that some effervescent and dispersible drug formulations may also contain citrate and should be restricted as well. Even if you do not have kidney problems, it may be best to separate the dosing of aluminum hydroxide and citrate-containing products by 2 to 3 hours. Talk to a healthcare professional if you have any questions or concerns. 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.

When aluminum hydroxide is taken during enteral nutrition therapy (tube feeding), the tube may get clogged. Therefore, aluminum hydroxide should not be mixed with or given after high-protein tube feedings. The dose should be separated from the feeding by as much as possible, and the tube should be thoroughly flushed before administration of the dose.

Ask your doctor before using acetaminophen together with ethanol (alcohol). This can cause serious side effects that 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.

Alcohol can increase the nervous system side effects of dextromethorphan such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with dextromethorphan. Do not use more than the recommended dose of dextromethorphan, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Ask your doctor before using diphenhydrAMINE together with ethanol (alcohol). Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking diphenhydrAMINE. You should be warned not to exceed recommended dosages and to avoid activities requiring mental alertness. If your doctor prescribes these medications together, you may need a dose adjustment to safely take this combination. 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.

Both phenylephrine and caffeine can increase blood pressure and heart rate, and combining them may enhance these effects. Talk to your doctor before using these medications, especially if you have a history of high blood pressure or heart disease. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. 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.

Consumer information for this interaction is not currently available.

MONITOR: Smoking cessation may lead to elevated plasma concentrations and enhanced pharmacologic effects of drugs that are substrates of CYP450 1A2 (and possibly CYP450 1A1) and/or certain drugs with a narrow therapeutic index (e.g., flecainide, pentazocine). One proposed mechanism is related to the loss of CYP450 1A2 and 1A1 induction by polycyclic aromatic hydrocarbons in tobacco smoke; when smoking cessation agents are initiated and smoking stops, the metabolism of certain drugs may decrease leading to increased plasma concentrations. The mechanism by which smoking cessation affects narrow therapeutic index drugs that are not known substrates of CYP450 1A2 or 1A1 is unknown. The clinical significance of this interaction is unknown as clinical data are lacking.

MANAGEMENT: Until more information is available, caution is advisable if smoking cessation agents are used concomitantly with drugs that are substrates of CYP450 1A2 or 1A1 and/or those with a narrow therapeutic range. Patients receiving smoking cessation agents may require periodic dose adjustments and closer clinical and laboratory monitoring of medications that are substrates of CYP450 1A2 or 1A1.