From the Guidelines
Doxazosin can have an indirect effect on the kidneys, primarily through its impact on blood pressure and urine flow, and should be used under close medical supervision in patients with kidney disease. Doxazosin, an alpha-1 blocker, is mainly used to treat high blood pressure and symptoms of an enlarged prostate. By relaxing blood vessels, doxazosin can potentially improve blood flow to the kidneys. Additionally, it may increase urine flow by relaxing muscles in the bladder and prostate. While doxazosin is not known to directly harm kidney function, patients with kidney disease should use it under close medical supervision, as changes in blood pressure can affect kidney performance. The typical starting dose is 1 mg once daily, which may be adjusted based on individual response and tolerability, as indicated in the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1. It's essential to consider the potential risks and benefits of doxazosin in patients with kidney disease, and to monitor their kidney function closely while on this medication.
Some key points to consider when using doxazosin in patients with kidney disease include:
- Monitoring blood pressure and kidney function regularly
- Adjusting the dose of doxazosin based on individual response and tolerability
- Being aware of the potential for orthostatic hypotension, especially in older adults
- Considering alternative medications if doxazosin is not well tolerated or if kidney function worsens.
Overall, while doxazosin can have an indirect effect on the kidneys, it can be a useful medication for treating high blood pressure and symptoms of an enlarged prostate, as long as it is used under close medical supervision in patients with kidney disease.
From the FDA Drug Label
Pharmacokinetic studies in elderly patients and patients with renal impairment have shown no significant alterations compared to younger patients with normal renal function.
The FDA drug label does not provide direct information on the effect of doxazosin on renal function, but it does mention that pharmacokinetic studies in patients with renal impairment showed no significant alterations compared to patients with normal renal function 2. However, this information is not directly related to the effect of doxazosin on renal function. Key points:
- No direct information on the effect of doxazosin on renal function is available.
- Pharmacokinetic studies in patients with renal impairment showed no significant alterations in doxazosin pharmacokinetics. The FDA drug label does not answer the question.
From the Research
Effect of Doxazosin on Renal Function
- Doxazosin has been studied in patients with chronic renal failure, and the results indicate that it can be an efficient depressor agent with renal protective actions 3.
- The pharmacokinetics of doxazosin are similar in patients with normal and impaired renal function, allowing for similar doses to be used in both groups 4.
- However, some studies have reported small reductions in glomerular filtration rates during long-term treatment with doxazosin, which may be due to a reduction in perfusion pressure or progression of the underlying renal disease 4, 5.
Renal Hemodynamics and Doxazosin
- Chronic administration of doxazosin has been shown to reduce glomerular filtration rate by 13% compared to pre-treatment, but no change in effective renal plasma flow was observed 5.
- Another study found a small but significant rise in serum creatinine levels during doxazosin therapy, which was considered compatible with the natural progression of the underlying renal pathology 6.
Safety and Efficacy of Doxazosin in Renal Impairment
- Doxazosin has been found to be effective and well-tolerated in the treatment of hypertension with concomitant renal insufficiency, without compromising renal function 6.
- The pharmacokinetics and effect on blood pressure of doxazosin have been studied in patients with renal failure, and the results indicate that doxazosin is not appreciably dialyzable 7.