# Chapter 13: Hypertension & the Kidney

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[Hypertension Module (29 lectures)](https://urinenephrology.org/2025_UDPA_Lectures_Live/hypertension/index.html) [🏆 Mastery: HTN Advanced](https://urinenephrology.org/mastery/hypertension-advanced/index.html)

## Introduction to Inpatient Hypertension

Severe hypertension (Systolic BP \>180 mmHg or Diastolic BP \>110 mmHg) is common in hospitalized patients, occurring in about 9-10% of admissions for non-hypertensive reasons. The management of this condition, particularly with intravenous (IV) antihypertensives, requires careful consideration of risks and benefits, especially in the absence of acute end-organ damage.

#### Hypertensive Urgency vs. Emergency

The central distinction in managing severe hypertension is determining whether it is an **urgency** or an **emergency**.

- **Hypertensive Emergency:** Severe hypertension with evidence of acute, ongoing target-organ damage (e.g., encephalopathy, myocardial infarction, acute pulmonary edema, aortic dissection, eclampsia). This requires immediate BP reduction with IV medications in an ICU setting.
- **Hypertensive Urgency (or Severe Asymptomatic Hypertension):** Severe hypertension without evidence of acute target-organ damage. There is no proven benefit to rapid BP reduction in this setting, and it may be harmful.

## Risks of IV Antihypertensive Use for Asymptomatic Hypertension

While IV antihypertensives like hydralazine and labetalol are effective at lowering blood pressure, their routine use for asymptomatic severe hypertension is associated with significant risks.

#### Potential Harms of Aggressive IV Treatment

- **Increased Adverse Events:** Rastogi 2021 JAMA Intern Med ([PMID 33369614](https://pubmed.ncbi.nlm.nih.gov/33369614/)) — propensity-matched cohort of 22,834 non-cardiac inpatients — found antihypertensive treatment intensification was associated with higher rates of acute kidney injury (10.3% vs 7.9%, p\<0.001) and **myocardial injury** (defined as troponin elevation; 1.2% vs 0.6%, p=0.003). The trial-published outcome is myocardial INJURY, not myocardial INFARCTION — these are distinct entities, and the lecture conflation has been corrected.
- **Excessive Blood Pressure Reduction:** IV agents can cause unpredictable and rapid drops in blood pressure (e.g., \>25% reduction in a few hours). This can lead to watershed ischemia and end-organ damage, particularly in patients with chronic hypertension whose autoregulatory curves have shifted.
- **Longer Hospital Stay:** Patients receiving PRN (as-needed) IV medications have been shown to have significantly longer hospital stays.

| Medication | Class | Onset | Duration | Key Considerations |
|----|----|----|----|----|
| **Labetalol** | Alpha/Beta Blocker | 2-5 min | 2-4 hr | Avoid in bradycardia, heart block, severe asthma. Good for most emergencies. |
| **Hydralazine** | Vasodilator | 5-20 min | 2-6 hr | Unpredictable response, can cause reflex tachycardia. Generally not a first-line agent. |
| **Nicardipine** | Calcium Channel Blocker | 1-5 min | 15-30 min (infusion) | Easily titratable infusion. Good for neurologic emergencies. |
| **Esmolol** | Beta Blocker | 1-2 min | 10-30 min | Very short-acting infusion, useful when beta-blockade needs to be titrated carefully (e.g., aortic dissection). |

Commonly Used IV Antihypertensives

## Evidence-Based Recommendations for Inpatient Hypertension

#### Guiding Principles for Inpatient Hypertension

1.  **Reserve IVs for Emergencies:** IV antihypertensives should be reserved for true hypertensive emergencies where there is clear evidence of acute, ongoing target organ damage.
2.  **Avoid Rapid BP Reduction:** In patients without a hypertensive emergency, the goal is gradual blood pressure control. Rapid reduction with IV agents may do more harm than good.
3.  **Prioritize Oral Agents:** For most patients with severe asymptomatic hypertension, restarting home medications or initiating scheduled oral agents is a safer and more appropriate strategy.
4.  **Treat the Cause:** Often, inpatient hypertension is a result of pain, anxiety, volume overload, or withdrawal. Addressing these underlying triggers should be the first step.

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