Amoxicillin is a semisynthetic derivative of penicillin and an analog of ampicillin that displays a broad spectrum of antibacterial activity against many gram-positive and gram-negative organisms. The compound is stable in the presence of stomach acids and may be given without regard to meals. Like other members of this class of antibiotics, amoxicillin exerts it's biological activity by inhibition of the biosynthesis of bacterial cell wall mucopeptides. Unfortunately, amoxicillin is not resistant to penicillinase so it is not effective against penicillinase-producing bacteria. Side effects include nausea, diarrhea, several hypersensitivity reactions, and occasionally dizziness and anxiety.