Renal Dosing Guidelines for Plaquenil (Hydroxychloroquine)
A reduction in the dosage of hydroxychloroquine is necessary in patients with renal impairment, and close monitoring of visual function by an ophthalmologist is essential if the drug is continued. 1
FDA-Approved Dosing Recommendations
The FDA label explicitly states that "a reduction in the dosage of hydroxychloroquine sulfate may be necessary in patients with hepatic or renal disease." 1
Hydroxychloroquine is substantially excreted by the kidney, and the risk of toxic reactions is greater in patients with impaired renal function. 1
Dose selection should start with the lowest recommended dose in patients with decreased renal function. 1
Critical Safety Considerations
The development of renal impairment without dose adjustment significantly increases the risk of severe retinal toxicity, even at standard recommended doses. 2
A documented case demonstrated severe hydroxychloroquine-induced retinal toxicity in a patient who developed chronic kidney disease stage 3 while maintained on the standard 400 mg daily dose without adjustment. 2
The patient experienced bilateral vision loss with grossly constricted visual fields after two years of unmonitored renal impairment. 2
Renal function must be monitored regularly in all patients on hydroxychloroquine, and if renal impairment develops, either discontinue the drug or reduce the dose with close ophthalmologic monitoring. 2
Practical Dosing Approach
While specific dose reduction percentages are not provided in the FDA label, the general principle for renally-cleared drugs suggests reducing the dose by approximately 25-50% when creatinine clearance falls below 30 mL/min. 3
Calculate creatinine clearance or glomerular filtration rate using online calculators to guide dosing decisions. 3
Maintenance dosing adjustments can be achieved through dose reductions, lengthening the dosing interval, or both. 3
Monitoring Requirements
Establish baseline renal function before initiating hydroxychloroquine therapy. 2
Monitor renal function periodically during treatment, with increased frequency in elderly patients and those with pre-existing renal disease. 1, 2
If renal impairment develops or worsens, arrange immediate ophthalmologic evaluation for baseline visual function assessment before continuing therapy. 2
Consider discontinuation rather than dose reduction in patients with severe renal impairment (creatinine clearance <30 mL/min) given the significant risk of retinal toxicity. 2
Common Pitfalls to Avoid
Do not continue standard dosing (400 mg daily) when renal function declines—this is the most critical error leading to severe retinal toxicity. 2
Avoid assuming that the "recommended daily dose" is safe regardless of renal function; hydroxychloroquine accumulates in renal impairment. 2
Do not rely solely on absence of visual symptoms, as retinal toxicity can progress silently until severe damage occurs. 2