Is it safe to use benzapril (Benazepril) in a patient with pyelonephritis and normal renal function?

From the Guidelines

Benazepril can be used in patients with pyelonephritis who have normal creatinine levels, but close monitoring of kidney function is essential. The use of ACE inhibitors like benazepril in patients with pyelonephritis requires careful consideration due to their potential effects on renal function, particularly in the context of infection-related kidney inflammation 1. Benazepril works by blocking the conversion of angiotensin I to angiotensin II, which helps lower blood pressure but can also reduce glomerular filtration pressure. In the setting of pyelonephritis, this could potentially impact renal perfusion.

Key Considerations

• Monitor kidney function closely during treatment as pyelonephritis can potentially affect renal function even when baseline creatinine appears normal.
• Start with the standard dosing of benazepril (usually 10 mg daily, adjustable based on blood pressure response) and arrange for follow-up creatinine testing within 1-2 weeks of starting therapy.
• Ensure the patient is adequately hydrated and that the underlying infection is being appropriately treated with antibiotics, as recommended by guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women 1.
• If the patient develops signs of worsening kidney function (rising creatinine, decreased urine output, or electrolyte abnormalities), consider temporarily discontinuing the benazepril until the infection resolves and renal function stabilizes.

Treatment of Pyelonephritis

The treatment of pyelonephritis involves the use of antibiotics, with the choice of agent depending on the severity of illness, local resistance patterns, and specific host factors 1. Oral ciprofloxacin (500 mg twice daily) for 7 days, with or without an initial 400-mg dose of intravenous ciprofloxacin, is an appropriate choice for therapy in patients not requiring hospitalization where the prevalence of resistance of community uropathogens to fluoroquinolones is not known to exceed 10% 1.

Conclusion Not Provided as per Guidelines

Instead, the key points to consider when using benazepril in a patient with pyelonephritis who has a normal creatinine level are:

• Close monitoring of renal function.
• Appropriate treatment of the underlying infection.
• Adjustment of benazepril dosing based on blood pressure response and renal function.
• Consideration of temporary discontinuation of benazepril if signs of worsening kidney function occur.

From the FDA Drug Label

1. 3 Impaired Renal Function Monitor renal function periodically in patients treated with benazepril hydrochloride. Changes in renal function, including acute renal failure, can be caused by drugs that inhibit the renin-angiotensin sytem. Patients whose renal function may depend on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe congestive heart failure, post-myocardial infarction, or volume depletion) may be at particular risk of developing acute renal failure on benazepril hydrochloride. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on benazepril hydrochloride.

The patient has pyelonephritis and normal creatinine levels.

• Key consideration: The presence of pyelonephritis may affect renal function, despite normal creatinine levels.
• Clinical decision: It is not explicitly stated in the label that patients with pyelonephritis and normal creatinine can safely use benzapril. However, the label does recommend monitoring renal function in patients with impaired renal function, and pyelonephritis may potentially impair renal function. Therefore, caution is advised when using benzapril in a patient with pyelonephritis, even with normal creatinine levels, and renal function should be closely monitored 2, 2.

From the Research

Safety of Benzapril in Pyelonephritis Patients with Normal Creatinine

• The provided studies do not directly address the safety of using benzapril in patients with pyelonephritis who have a normal creatinine level 3, 4, 5, 6, 7.
• However, it is known that benzapril is an angiotensin-converting enzyme (ACE) inhibitor, which can affect kidney function.
• Patients with pyelonephritis may be at risk of developing kidney damage or worsening of existing kidney disease, and the use of ACE inhibitors like benzapril may need to be carefully considered in these patients.
• The studies provided focus on the diagnosis and treatment of acute pyelonephritis, including the use of antibiotics such as fluoroquinolones, cephalosporins, and aminoglycosides 3, 4, 5.
• One study discusses the importance of monitoring renal function in patients with acute pyelonephritis, particularly when using nephrotoxic drugs like amikacin, and suggests that cystatin C may be a better marker for determining and monitoring renal function than creatinine 7.
• However, there is no direct evidence provided on the safety of using benzapril in patients with pyelonephritis and normal creatinine levels.

Considerations for Benzapril Use

• When considering the use of benzapril in a patient with pyelonephritis and a normal creatinine level, it is essential to weigh the potential benefits and risks of the medication.
• The patient's overall health status, including the severity of the pyelonephritis and any underlying kidney disease, should be taken into account.
• Close monitoring of the patient's kidney function, including regular measurements of creatinine and possibly cystatin C, may be necessary to ensure safe use of benzapril 7.