What phase of the clinical trial is conducted after the drug has been approved for marketing?

The phase of the clinical trial conducted after a drug has been approved for marketing is known as Phase 4. This phase is also referred to as post-marketing surveillance or post-market studies. During Phase 4 trials, the drug is monitored in the general population to gather more information about its long-term effects, optimal use, and the risk of rare side effects that may not have been noticeable during earlier phases of testing.

In this phase, data is collected on the drug's performance in a wider and more diverse group of patients outside the controlled conditions of earlier trials. It helps ensure that the benefits of the drug continue to outweigh any potential risks once it is widely used. This ongoing monitoring is crucial for maintaining drug safety and efficacy and contributes to the overall understanding of the medication within the healthcare system.