The long-standing issue of inadequate medicine formulations has been a focus of regulatory bodies and pharmaceutical research, particularly in adapting medicines for children’s unique requirements. The pediatric population presents diverse challenges in pharmacotherapy due to their varying age-related physiological differences, taste and dosage form preferences. Conventional formulations often fail to meet these needs, leading to high prevalence of off-label medication use and modifications by caregivers, which can compromise drug efficacy and safety. The well-known problems of managing children's medication are very similar to those encountered in geriatrics, which also require doses to be adapted to the patient's pathophysiological characteristics to avoid deglutination problems. This paper explores recent innovations in drug formulations, highlighting the shift from traditional liquid formulations to solid dosages through 3D printing technology. Recent advancements in 3D printing technology offer promising solutions to these challenges. Additive manufacturing (AM), or 3D printing, facilitates the creation of complex objects including drug formulations, directly from digital models, allowing for high precision and customization. 3D printed formulations have shown considerable promise in improving palatability, adherence, and dose accuracy for pediatric use. Innovations like chewable tablets and taste-masked formulations make medications more acceptable to children. Moreover, the ability of 3D printing to adjust drug release profiles and doses offers a personalized approach to pediatric and geriatric pharmacotherapy, essential for conditions requiring tight therapeutic control. The paper discusses several case studies based on the semi-solid extrusion (SSE) process that enables the production of personalized dosage forms and the various technical and regulatory challenges to implementing this process in hospitals for drug manufacturing.  In conclusion, while 3D printing in pediatric and geriatric pharmacotherapy addresses many challenges of traditional drug formulations, ongoing research and adaptation of regulatory frameworks are necessary to expand its application, ensuring safer, more effective, and more acceptable medication.