Purpose
The concept of an integrated curriculum is not clearly defined, posing potential challenges for pharmacology educators. This study reports the lessons learned from our experience of integrating pharmacology into the medical school curriculum.

Methods
Pharmacology educators from three U.S. medical schools assessed the scope and extent of pharmacology integration within their institutions' curricula. We also reviewed the published literature about medical curriculum integration. The level of integration was compared, potential areas for improvement were identified, and best practices were discussed.

Results
We found that most pharmacology education is horizontally integrated into organ system-based modules during the first two years of the medical curriculum. In horizontal integration, pharmacology sessions are coordinated with other organ system courses to follow a weekly theme. We reached a consensus that foundational pharmacology topics, including pharmacodynamics, pharmacokinetics, toxicology, and autonomic pharmacology, which do not align seamlessly with organ system-based modules, should be taught with standalone foundational module during the first semester. Conversely, vertical integration is more challenging for pharmacology, especially in the third and fourth years of the curriculum. Successful vertical integration requires collaboration with clerkship faculty and the reintroduction of pharmacology as an elective course. Active learning pedagogies such as case-based learning have proven very effective for integrating pharmacology. We found that incorporating open-ended questions during case-based sessions enhances students' grasp of factual knowledge. This approach not only assesses their understanding of pharmacological concepts but also strengthens their ability to apply this knowledge effectively in clinical scenarios.

Conclusion
Based on the experiences of our institutions, we conclude that pharmacology can be effectively integrated into the medical curriculum with certain adjustments. We strongly believe that opportunities remain to further enhance this integration, particularly by incorporating pharmacology into the clinical sciences during the third and fourth years of the curriculum.