II. Epidemiology
- See Refractory Hypertensive Populations
- Prevalence: May approach 20-30% of hypertensive patients
III. Definitions
- Resistant Hypertension
- Blood Pressure above goal despite adherance to Antihypertensive regimen of 3 medications
IV. Indications: Combination Antihypertensive Therapy
V. Risk Factors: Populations with Hypertension that is difficult to treat
- African-American
- Hispanic
- Diabetes Mellitus
- Renal Insufficiency or Renal Failure
- Elderly (especially Isolated Systolic Hypertension)
- Stage 3 Hypertension or greater
- Obese Patients
VI. Efficacy
- Adding a medication to protocol has five fold greater efficacy over doubling dose of current medications
- Combination agents are preferred over monotherapy esp. for BP>160/100 mmHg or >20/10 above goal
VII. Causes: Resistant Hypertension
- Noncompliance with current regimen (pseudoresistance, most common in up to 80% of patients)
- Recent drug holiday
- Unfilled prescription
- Frequently missed doses (ask this in a non-judgemental way)
- Lifestyle modification (e.g. DASH Diet, Weight loss, Exercise, Tobacco Cessation) not employed
- Inaccurate Blood Pressure Measurement (see BP Examination regarding pitfalls)
- Example: BP cuff that is too small will artificially inflate Blood Pressure readings
- White coat Hypertension
- Consider Ambulatory Blood Pressure Monitoring
- Increase regimen if average 24 hour BP > 129/79 or daytime average BP >134/84
- Pseudohypertension (elderly patients with atherosclerosis)
- Progression of disease
- Most Hypertension patients will require more than one agent for adequate Blood Pressure control
- Treatment program not optimized
- Example: Thiazide Diuretics are ineffective at GFR <30 ml/min (use Loop Diuretics instead)
- Medications or drugs counteracting Antihypertensive (e.g. NSAIDS, Sympathomimetics)
- Comorbid condition (e.g. Sleep Apnea, morbid Obesity, Alcohol Abuse, anxiety, Chronic Pain)
-
Secondary Hypertension
- See Secondary Hypertension Causes
-
Obstructive Sleep Apnea
- Very common cause of Resistant Hypertension
-
Hyperaldosteronism
- Represents 20% of refractory cases (consider especially if Hypokalemia)
- Use Spironolactone or Eplerenone
- Check Serum Potassium and Serum Creatinine 2 weeks after start and then every 6 months
-
Chronic Kidney Disease is common
- Follow a salt restricted diet
- Use Diuretics with an ACE Inhibitor or Angiotensin Receptor Blocker
- Check Serum Potassium and Serum Creatinine 2 weeks after start and then every 6 months
-
Hyperuricemia
- Experimental lowering of serum Uric Acid with Allopurinol results in signficant lowering of Blood Pressure
- Reference
VIII. Preparations: Combinations (assist with cost and compliance)
- Prinizide (Lisinopril 10-20 mg with Hydrochlorothiazide 12.5-25 mg)
- Diovan-Hct (Valsartan 80-160 mg with Hydrochlorothiazide 12.5 mg)
- Ziac (Bisoprolol with Hydrochlorothiazide 6.25)
- Lotrel (Benzapril 10-20 mg with Amlodipine 2.5-10 mg)
- Tarka (Trandolopril 1-2 mg with Verapamil 180-240 mg)
- Exforge (Valsartan and Amlodipine)
- Reserpine 1.25-2.5 mg with Hydrochlorothiazide 25 mg
- Tenoretic (Atenolol 50-100 mg with Chlorthalidone 25 mg)
IX. Preparations: Combinations that add 4 drugs in 2 pills for $50-60
- Tenoretic 100/25 with Lotrel 10/20
- Tenoretic 100/25 with Prinizide 20/12.5
X. Protocol: Approach
- Consider reasons for Resistant Hypertension (see below)
- Review Hypertension Risk Stratification
- Determine Hypertension Reduction Goal
- Advance to next step if BP>15/10 above goal
- Consolidate medications into combination agents and once daily regimens
- Consider optimal strategies in specific populations when selecting medications
- Consider at least one non-diuretic Antihypertensive at bedtime (e.g. Beta Blocker)
XI. Protocol: Step 1 (combination agents)
-
Serum Creatinine <1.5 to 1.8 mg/dl
- ACE Inhibitor (or ARB) and Thiazide Diuretic
- Chlorthalidone (or Inapamide) is preferred as more potent and longer acting than Hydrochlorothiazide
-
Serum Creatinine >1.5 to 1.8 mg/dl (or GFR <30 ml/min)
- ACE Inhibitor and Loop Diuretic (Lasix typically twice daily or Torsemide once daily)
- Alternative
- Angiotensin Receptor Blocker may be used instead of an ACE Inhibitor (equivalent efficacy, fewer adverse effects)
- Avoid combination of ACE Inhibitor with Angiotensin Receptor Blocker
XII. Protocol: Step 2
- Add Non-Dihydropyridine Calcium Channel Blocker (e.g. Diltiazem, Verapamil)
- Alternatively, consider Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine, Nifedipine)
XIII. Protocol: Step 3
- Some guidelines recommend using the step 4 agents (e.g. Spironolactone) before the step 3 agents
- Spironolactone is often more effective in Resistant Hypertension
-
Heart Rate >80-85 bpm (or if CAD, CHF or other Beta Blocker specific indication)
- Add low dose Beta Blocker
- However, Beta Blockers are unlikely to substantially decrease resistant Blood Pressure
- Consider Labetalol or Carvedilol instead of a Beta Blocker
- Combined alpha-beta adrenergic blocker effect
- Add low dose Beta Blocker
- Heart Rate <80-85 bpm
XIV. Protocol: Step 4
- Consider Spironolactone 12.5 to 50 mg orally daily
- Counters the Sodium retention often present in Resistant Hypertension
- Dosing of 100 mg offers no added benefit compared with 50 mg dose
- Monitor Renal Function and Potassium (at baseline, again in 2 weeks and then periodically)
- Consider Alpha-Beta Adrenergic blocker (Labetolol)
- If not already added above (do not combine with Beta Blockers)
XV. Protocol: Step 5
- Consider Central Adrenergic Agonist (e.g. Clonidine, Guanfacine)
- Risk of sedation and Xerostomia
- Consider Hydralazine (Apresoline)
- Consider Reserpine (risk of Major Depression)
- Consider long acting Alpha adrenergic blocker at night (e.g. Terazosin), especially in BPH
XVI. Protocol: Step 6
- Consult Nephrology or Cardiology
XVII. Protocol: Additional Measures
- Consider Renal Sympathetic Denervation
- Consider Tekturna (Aliskiren), a Direct Renin Inhibitor
- No significant benefit in Hypertension, Chronic Kidney Disease, Heart Failure
- Risk of hyptension, Hyperkalemia and increased Serum Creatinine
- (2016) Presc Lett :3(6):34
XVIII. References
- Woolley (2007) Park Nicollet Primary Care Conference, Minneapolis, MN
- Schwartz (2008) Mayo Selected Topics in Internal Medicine, Lecture
- Garg (2005) Am J Hypertens 18:619-626 [PubMed]
- James (2014) JAMA 311(5): 507-20 [PubMed]
- Moser (2006) N Engl J Med 355(4): 385-92 [PubMed]
- Viera (2009) Am Fam Physician 79(10): 863-9 [PubMed]