From the Guidelines
Loop diuretics should be held in patients with low diastolic blood pressure (DBP), typically below 60 mmHg, to avoid further reducing blood pressure and potentially causing hypoperfusion of vital organs. This recommendation is based on the potential risks associated with low DBP, including dizziness, lightheadedness, and confusion, as well as the potential for decreased cardiac output in patients with heart failure 1. When a patient presents with low DBP, especially if symptomatic, temporarily withholding the diuretic and reassessing is appropriate.
Key Considerations
- Fluid status should be evaluated before resuming therapy, and when restarting, consider using a lower dose or extending the dosing interval.
- Loop diuretics work by inhibiting sodium and chloride reabsorption in the ascending loop of Henle, leading to increased urine output and reduced intravascular volume, which can further decrease blood pressure.
- In patients requiring continued diuresis despite low DBP, careful monitoring of blood pressure, electrolytes (particularly potassium, sodium, and magnesium), and renal function is essential.
- Alternative strategies for managing fluid overload might include sodium restriction, gradual fluid removal, or consideration of other medication adjustments before resuming the loop diuretic.
Diuretic Dosing
The European Society of Cardiology guidelines provide practical guidance on the use of diuretics, including the doses of commonly used diuretics, such as furosemide, bumetanide, and torsemide 1. The aim of using diuretics is to achieve and maintain euvolaemia (the patient’s ‘dry weight’) with the lowest achievable dose, and the dose must be adjusted, particularly after restoration of dry body weight, to avoid the risk of dehydration leading to hypotension and renal dysfunction.
Clinical Implications
In clinical practice, it is essential to carefully evaluate the patient's volume status and blood pressure before initiating or continuing loop diuretic therapy, especially in patients with low DBP. By prioritizing the patient's safety and adjusting the diuretic dose accordingly, clinicians can minimize the risk of adverse effects and optimize the management of fluid overload.
From the Research
Loop Diuretics and Low Diastolic Blood Pressure
- There is no direct evidence to suggest that loop diuretics should be held in patients with low diastolic blood pressure (DBP) 2, 3, 4, 5, 6.
- Loop diuretics are often used to control volume in patients with low glomerular filtration rate, but their use in patients with low DBP is not well established 2.
- The blood pressure lowering efficacy of loop diuretics is modest, with a systolic/diastolic blood pressure lowering effect of -8/-4 mmHg 3, 5, 6.
- The use of loop diuretics in patients with primary hypertension is not recommended as first-line therapy, but rather for conditions of clinically significant fluid overload or advanced renal failure 4.
Considerations for Loop Diuretic Use
- The dose-related decrease in systolic and/or diastolic blood pressure due to loop diuretics is not well established 3, 5, 6.
- Adverse events leading to patient withdrawal and adverse biochemical effects due to loop diuretics are not significantly different from placebo 3, 5, 6.
- The quality of evidence for the blood pressure lowering effect of loop diuretics is graded as "low" due to the high risk of bias and publication bias 6.