Additive Hypotension Risks

Additive hypotension is a haemodynamic problem, not merely an abnormal blood-pressure reading. Vasodilation, reduced sympathetic tone, intravascular volume loss, and reduced cardiac output can converge until cerebral, renal, or coronary perfusion falls. The pattern often appears after a new prescription, a PRN dose, alcohol, poor intake, vomiting or diarrhoea, or a positional change. A patient may have an acceptable seated BP yet become presyncopal when standing because the baroreflex cannot compensate for the combined fall in vascular tone and circulating volume. Read the medication list as one haemodynamic system: scheduled and PRN drugs, OTC products, supplements, and medications prescribed by other clinicians all contribute. Most symptomatic cases require identifying the least essential contributor, correcting reversible volume loss when safe, and avoiding treatment targets that create falls. Hypertension Canada's 2025 primary-care guideline targets systolic BP below 130 mm Hg for most adults, but orthostatic hypotension, frailty, and fall risk are reasons to relax that target. One interaction is a hard stop rather than a titration problem: any nitrate or nitrite with a PDE5 inhibitor. The exact drug, route, and timing must...