Resistant hypertension: What are the clues?
M3 India Newsdesk Mar 04, 2022
In this article, we discuss the treatment and management of patients with resistant hypertension encountered by clinicians on a regular basis.
What is resistant hypertension?
Resistant hypertension is the blood pressure that remains above target despite adherence to an appropriate regimen of three antihypertensive drugs from different classes (including a diuretic), all of which are prescribed at appropriate antihypertensive doses and after the white coat effect is ruled out whereas, controlled resistant hypertension can be defined as the blood pressure that takes at least four drugs to maintain control.
Resolving the following factors may lead to pseudo/true resistant hypertension:
- Incorrect blood pressure measurement (eg, using an inappropriately small blood pressure cuff, not allowing a patient to rest quietly before taking readings)
- Poor compliance to blood pressure medications
- Poor compliance to lifestyle and dietary approaches to lower blood pressure\s
- Suboptimal antihypertensive therapy, due either to insufficient doses, an improper drug combination, or exclusion of a diuretic from the antihypertensive regimen\s
- Whitecoat hypertension\s
- Extracellular volume expansion\s
- Increased sympathetic activation\s
- Ingestion of substances that can elevate the blood pressure, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or stimulants\s
- Secondary or contributing causes of hypertension
Detection and addressing secondary causes
One of the most important aspects of managing resistant hypertension is identifying and treating possibly reversible secondary hypertension causes.
Common causes:
- Obstructive sleep apnoea
- Renal parenchymal disease
- Primary aldosteronism
- Renal artery stenosis
Uncommon causes:
- Pheochromocytoma
- Cushing's disease
- Hyperparathyroidism
- Aortic coarctation
Using blood pressure-raising drugs
Several drugs can elevate blood pressure and exacerbate pre-existing hypertension like:
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Oral contraceptives
- Antidepressants (eg, tricyclic antidepressants, selective serotonin reuptake inhibitors)
- Corticosteroids (including glucocorticoids and mineralocorticoids)
- Decongestants (eg, phenylephrine, pseudoephedrine)
- Some weight-loss medications (eg, phentermine, diethylpropion)
- Sodium-containing antacids
- Erythropoietin
- Cyclosporine or tacrolimus
- Cocaine or methamphetamine
- Stimulants (eg, methylphenidate, amphetamines)
- Atypical antipsychotics (eg, clozapine, olanzapine)
- Angiogenesis inhibitors (eg, bevacizumab)
- Tyrosine kinase inhibitors (eg, sunitinib, sorafenib)
Recommend a change in lifestyle
Weight reduction, exercise, and eating a nutritious diet are all examples of lifestyle changes that can improve one's health and reduce blood pressure. The following are the primary modifications:
- Following the DASH diet (Dietary Approaches to Stop Hypertension).
- Increasing potassium consumption and decreasing sodium consumption.
- Getting rid of extra pounds (in obese and overweight people).
- Moderate consumption of alcohol.
Noncompliance with antihypertensive treatment
To decrease the number of prescribed tablets and allow once-daily administration, regimens should be reduced as much as feasible, and long-acting combination medications should be employed as much as feasible. As the usage of tablets, the complexity of the dosage schedule, and out-of-pocket expenditures rise, so does treatment adherence.
Medication-related side effects should be examined, and side effects should be handled, with the offending drug being down-titrated or replaced. The most challenging patients to treat are those who have actual or perceived adverse effects from a variety of antihypertensive medicines.
Pharmacologic treatment
The main strategy is to mix agents with various mechanisms of action in a sequential manner. An ACE inhibitor or angiotensin receptor blocker (ARB), a long-acting dihydropyridine calcium channel blocker (typically amlodipine), and a long-acting thiazide-like diuretic is a common and well-tolerated triple combination.
Furthermore, drugs should be given at a maximally tolerated dosage and administered at the proper dosage frequency in individuals with uncontrolled blood pressure.
Switching to a more potent diuretic (if necessary)
Most individuals with resistant hypertension are treated with stronger diuretic treatment as the first line of defence. It is recommended to switch to a thiazide-like diuretic in patients who are using a thiazide-type diuretic (eg, hydrochlorothiazide) and have an eGFR of less than 30 mL/min/1.73 m2 (either chlorthalidone or indapamide).- Adding a loop diuretic to a thiazide-like diuretic in patients with an eGFR of less than 30 mL/min/1.73 m2 who are currently on a thiazide-like diuretic and have persistent indications of hypervolemia (oedema) (ie, sequential nephron blockade) can also be suggested.
- If a patient's eGFR is less than 30 mL/min/1.73 m2, switching to a loop diuretic is preferred; if they're currently on one, we recommend increasing the loop diuretic dose until the patient shows evidence of hypovolemia. Because furosemide and bumetanide have a short half-life, they must be taken at least twice a day.
- Torsemide, a loop diuretic having a longer action time and more steady absorption, may be more effective. When switching diuretics or changing dosage, it's important to keep an eye on your electrolytes. Patients with resistant hypertension are more likely to develop hypokalaemia.
- The thiazide-like diuretics, such as chlorthalidone and indapamide, are favoured over hydrochlorothiazide for the treatment of resistant hypertension in individuals without significant renal impairment. Include a mineralocorticoid receptor antagonist in the combination (if necessary).
- A mineralocorticoid receptor antagonist can be added to individuals with resistant hypertension and uncontrolled blood pressure despite robust diuretic treatment (spironolactone or eplerenone) If a mineralocorticoid receptor antagonist is not available, a potassium-sparing diuretic (e.g., amiloride, triamterene) can be used instead.
Other medications
Even using a four-drug regimen that includes a thiazide-like diuretic, such as chlorthalidone, and a mineralocorticoid receptor blocker, such as spironolactone, some individuals remain hypertensive. Those who have a high heart rate (e.g., >70 beats per minute) may improve from taking a beta-blocker next.
When compared to typical beta-blockers, vasodilating beta-blockers such as labetalol, carvedilol, or nebivolol may give more antihypertensive effectiveness with fewer side effects, especially when large dosages are administered.
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Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.
The author is a practising super specialist from New Delhi.
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