Certain classes of antibiotics
Certain classes of antibiotics like macrolides, sulfonamides, and tetracyclines.
Cancer treatment drugs like methotrexate – Studies indicate that using amoxicillin while being treated with methotrexate. This boosts the blood’s overall methotrexate concentration and increases toxicity
Apart from the treatments above, amoxicillin might also have an adverse interaction with certain glucose tests. Urine tests for glucose which use Fehling’s solution, Benedict’s solution, and Clinitest have been shown to produce false-positive results. This reaction was observed only with ampicillin but since it shares the same antibiotic class as amoxicillin, its adverse interaction with glucose tests is deemed to apply to amoxicillin as well. The work around to this issue is to use tests that use enzyme reactions like Tes-Tape or Clinistix.