What is ampicillin: Indications, side effects and contraindications The main types of penicillins are: penicillinase-resistant penicillins, antipseudomonal penicillins, beta-lactamase inhibitors, natural penicillins, aminopenicillins. Narrow spectrum penicillins (beta-lactamase sensitive, beta-lactamase resistant) and broad spectrum penicillins (aminopenicillins, carboxypenicillins, ureidopenicillins) are known. The main representatives of aminopenicillins are: amoxicillin, ampicillin, pivampici