Cefoxitin and imipenem (N-formimidoyl thienamycin) can be antagonistic to aztreonam.
D000900:Anti-Bacterial Agents / Q000037:antagonists & inhibitors*; D001398:Aztreonam; D002440:Cefoxitin / Q000494:pharmacology*; D015378:Imipenem; D013845:Thienamycins / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D013845:Thienamycins; D002440:Cefoxitin; D015378:Imipenem; D001398:Aztreonam