What Are Possible Amoxicillin Interactions?

Amoxicillin interactions can include adverse drug combinations as well as conflicts with underlying medical conditions. Medications like methotrexate, other antibiotics, birth control, and certain antivirals can conflict with amoxicillin. Patients with colitis and kidney disorders may not be able to take this medication safely, or could need a dosage adjustment. Before people start taking amoxicillin, they can discuss their medical history with a care provider to determine if it is appropriate for their needs.

Methotrexate, a medication used to treat a variety of conditions including some cancers, can conflict with amoxicillin. Both drugs are processed through the kidneys, which may not be able to handle them together. This can lead to a rise in methotrexate levels in the blood, which may cause side effects. Medical professionals may recommend against combining these two medications, because the drug interaction can be significant. Patients already taking methotrexate to treat an existing health problem can discuss options and alternatives if they need to take antibiotics for an infection.

Other antibiotics can also conflict with amoxicillin, because they are often processed through the kidneys as well and the two drugs might overload the capacity of the kidneys, causing one or more to have an increased concentration. Patients may also be advised against combining antibiotics because this can contribute to the development of drug resistance. Warfarin, an anticoagulant medication, also has been known to cause amoxicillin interactions. Frequent bleeding and bruising can occur because the body cannot eliminate the warfarin fast enough and it interferes with normal clotting.

Entecavir, an antiviral medication commonly used to treat hepatitis B infections, is also associated with amoxicillin interactions. Hormonal birth control can be less effective while patients take amoxicillin, and a backup method is recommended to prevent pregnancy. It is important to keep using that method for several days after the antibiotic therapy ends to make sure the amoxicillin is completely eliminated from the body, giving the birth control the chance to start working again.

Other amoxicillin interactions can involve underlying medical conditions. This medication can increase gastrointestinal irritation for patients with colitis, an inflammation of the bowel. They may experience diarrhea, abdominal cramping, and discomfort while on the antibiotic. Additionally, patients with kidney dysfunction, especially if they need dialysis to support failing kidneys, can experience amoxicillin interactions. These patients cannot clear the medication through normal metabolism and could be at risk of severe side effects without a dosage adjustment to reduce the load on the kidneys.