Which of the following is NOT an antipseudomonal penicillin?

Dicloxacillin is not classified as an antipseudomonal penicillin because it is primarily effective against staphylococci and not specifically designed to target Pseudomonas aeruginosa infections. Unlike antipseudomonal penicillins, which include piperacillin, ticarcillin, and carbenicillin, dicloxacillin is a penicillinase-resistant penicillin. This means its main role is to provide coverage against penicillin-resistant strains of staphylococci, rather than providing the broad-spectrum activity against Pseudomonas that the other options are known for.

Piperacillin, ticarcillin, and carbenicillin are specifically developed to have activity against Pseudomonas aeruginosa and some other Gram-negative bacteria. These agents are often used in clinical settings where infections caused by Pseudomonas are a concern, making them essential tools in treating serious infections, especially in immunocompromised patients.