“My home machine gives me totally different numbers every time — I don’t know what to believe”

Wildly variable home BP readings should be interpreted SYSTEMATICALLY, not reacted to by chasing the highest number or dosing reactively (which is unsafe and anxiety-driven). Most variability is a MEASUREMENT/technique or physiological issue: check a validated, calibrated machine and correct CUFF SIZE (too-small over-reads), ensure the patient is seated, relaxed and rested for a few minutes with the arm supported at HEART LEVEL, feet flat, not talking, with no caffeine/smoking/exercise/full bladder beforehand, follows the NICE NG136 home protocol — two readings at least a minute apart, morning and evening, for at least 4 and ideally 7 days, DISCARDING THE FIRST DAY and AVERAGING the rest — measures at a consistent time, and uses the higher-reading arm if the two arms differ by more than 15 mmHg on repeat — correcting these often resolves the "wild" swings. Recognise WHITE-COAT and situational rises and the ANXIETY cycle (worry raises readings, which raises worry), and treat the anxiety as part of management without dismissing genuinely elevated averages. Importantly, ask about POSTURAL HYPOTENSION (NG136 checks standing BP in people with falls or postural dizziness, type 2 diabetes, or aged 80 and over; here her low readings on amlodipine justify a face-to-face check; a systolic fall of 20 mmHg or more is significant, and the diastolic ≥10 criterion is international consensus) — the low readings and possible over-treatment may matter as much as the high ones — and consider an IRREGULAR PULSE/ARRHYTHMIA such as atrial fibrillation, which makes oscillometric home monitors unreliable and erratic (palpate the pulse face to face, measure BP manually by auscultation if it is irregular, arrange an ECG per NICE NG196, and note AF changes overall management). Also consider adherence, pain and device error. Then STANDARDISE: teach correct home monitoring, arrange ABPM or properly standardised clinic/home readings to get a true picture, and review medication on reliable data. The hidden agenda is anxiety (fear of imminent stroke, temptation to over-dose) that itself raises readings — reassure with a clear systematic explanation, restore confidence with a correct-monitoring routine, screen the genuinely important things (postural drop, arrhythmia, true average), and review on reliable data, calming the anxiety while not missing real pathology.