A cheap, long-established medicine that eases a sudden dizzy spell in its first hours and lowers the odds of travel sickness. Beyond that window the benefit evaporates; daily use is no better than a dummy tablet. Drowsiness and slowed thinking are near-universal, falls rise, and sustained exposure is tied to later memory decline. The longevity story rests on rodents. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Anticholinergic burden score | 0–2 total across all medications | Predicts dementia and fall risk better than any single drug |
| MoCA cognitive screen | 26–30 of 30 | Detects drug-related cognitive decline before it becomes obvious |
| Timed Up and Go test | Under 10 seconds | Direct functional proxy for the fall risk meclizine amplifies |
| Orthostatic blood pressure | Systolic drop under 20 mmHg on standing | Separates drug sedation from a circulatory cause of dizziness |
| Epworth Sleepiness Scale | 0–10 of 24 | Quantifies the daytime sedation that drives most real-world harm |
| Post-void residual bladder volume | Under 50 mL | Detects anticholinergic urinary retention before it becomes acute |
| Intraocular pressure | 10–18 mmHg | Identifies eyes at risk of drug-precipitated angle closure |
| Serum creatinine and eGFR | eGFR above 80 mL/min/1.73 m² | Reduced clearance raises effective exposure at a standard dose |
| CYP2D6 genotype | No established target; record the metaboliser phenotype and dose to it | Determines how much drug a standard tablet actually delivers |
Cadence: Event-driven for intermittent users: reassessment after the first dose, at 4 weeks, then every 6–12 months while use continues. At more than 30 dosing days a year, the cognitive screen and mobility test are repeated annually and the burden score recalculated at every medication change.