Drug Interaction Report

Using pyrilamine together with dihydrocodeine may increase side effects such as dizziness, drowsiness, confusion, and difficulty concentrating. Some people, especially the elderly, may also experience impairment in thinking, judgment, and motor coordination. You should avoid or limit the use of alcohol while being treated with these medications. Also avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medications affect you. Talk to your doctor 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.

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with vadadustat may increase the plasma concentrations of drugs that are substrates of the CYP450 3A4 and/or CYP450 2C8 isoenzymes. Vadadustat is an inhibitor of CYP450 3A4 and CYP450 2C8 in vitro. However, clinical data are not available.

MANAGEMENT: Some authorities recommend using caution when vadadustat is used concomitantly with drugs that are substrates of CYP450 3A4 and/or CYP450 2C8, particularly sensitive substrates or those with a narrow therapeutic range. Monitoring for signs and symptoms of increased exposure to the CYP450 3A4 and/or CYP450 2C8 substrate should be considered whenever vadadustat is added to or withdrawn from therapy. The prescribing information for concomitant medications may be consulted to assess the benefits versus risks of coadministration, as well as any dosage adjustments that may be required during coadministration and/or following the discontinuation of a CYP450 3A4 and/or CYP450 2C8 inhibitor.

Alcohol can increase the nervous system side effects of pyrilamine 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 pyrilamine. Do not use more than the recommended dose of pyrilamine, 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.

Consumer information for this interaction is not currently available.

MONITOR: Smoking and alcohol consumption during therapy with vadadustat may increase the risk of gastrointestinal erosions. Serious erosions, including gastrointestinal bleeding and the need for red blood cell transfusions, have been reported during vadadustat clinical trials. Patients with a history of gastrointestinal erosion, peptic ulcer disease, and current tobacco smokers and alcohol drinkers may be at higher risk of gastrointestinal injury.

MANAGEMENT: Caution is advised if vadadustat is prescribed to current tobacco smokers or alcohol drinkers. Patients should be advised to contact their physician if they develop potential signs and symptoms of gastrointestinal injury such as abdominal pain, hematemesis, trouble swallowing, chest or throat pain, and/or black, tarry stools.

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.