Resistant and secondary hypertension

Synopsis

Confirm true resistant hypertension, identify pseudo-resistance and secondary causes, then add evidence-based step-4 treatment with safe biochemical monitoring.

• NICE resistant hypertension means BP remains above the person's age- and comorbidity-appropriate NICE target despite optimal tolerated ACE inhibitor or ARB plus calcium-channel blocker plus thiazide-like diuretic, with elevation confirmed by ABPM or HBPM before step 4.
• Before step 4, confirm elevated BP with ABPM or HBPM, assess postural BP and discuss adherence.
• Exclude pseudo-resistance: wrong cuff/technique, white-coat effect, missed doses, under-dosing, excess salt/alcohol and pressor medicines/substances.
• Common secondary causes include primary aldosteronism, CKD, obstructive sleep apnoea, renovascular disease and medicines; endocrine tumours are less common but important.
• If potassium is 4.5 mmol/L or less, consider low-dose spironolactone at step 4, with particular caution in reduced eGFR.
• If potassium is above 4.5 mmol/L, consider an alpha-blocker or beta-blocker rather than spironolactone.
• Check sodium, potassium and renal function within 1 month of starting further diuretic therapy and whenever illness or interacting medicines increase risk.
• If BP remains uncontrolled on optimal four-drug therapy, seek specialist hypertension advice; young onset under 40 also warrants specialist secondary-cause evaluation.