Dihydropyridine calcium channel blockers, commonly prescribed blood pressure medications, triggered unnecessary prescribing of 24 different drug classes among 388,862 Medicare patients aged 66 and older. The analysis identified prescribing cascades where side effects from the blood pressure drugs led doctors to prescribe additional medications rather than addressing the root cause. The strongest signals included hemostatic drugs (adjusted sequence ratio 2.99), nasal preparations (1.99), and erectile dysfunction medications (1.85). Prescribing cascades represent a critical but underrecognized problem in geriatric medicine, where medication side effects masquerade as new medical conditions requiring treatment. This creates a domino effect of polypharmacy that increases costs, drug interactions, and patient burden. The Medicare claims analysis spanning 2011-2020 provides the largest systematic evidence to date of this phenomenon with calcium channel blockers. However, as this is a preprint awaiting peer review, the findings require validation through independent replication and clinical confirmation. The observational design also cannot definitively prove causation between the blood pressure medications and subsequent prescriptions, though the temporal patterns strongly suggest inappropriate prescribing cascades affecting hundreds of thousands of older adults.