What is the recommended starting dose of Reglan (metoclopramide) for a patient with impaired renal function, specifically a creatinine level of 1.84 and an estimated Glomerular Filtration Rate (GFR) of 36.2?

Metoclopramide Dosing in Moderate Renal Impairment

For a patient with creatinine clearance of approximately 36 mL/min, initiate metoclopramide at 5 mg (half the standard dose) rather than the usual 10 mg, as the FDA label explicitly recommends starting at approximately one-half the recommended dosage when creatinine clearance is below 40 mL/min. 1

FDA-Mandated Dose Reduction

• The FDA drug label for metoclopramide clearly states that therapy should be initiated at approximately one-half the recommended dosage in patients whose creatinine clearance is below 40 mL/min. 1
• After initiating at the reduced dose, the dosage may be increased or decreased based on clinical efficacy and safety considerations. 1
• This dose reduction is necessary because metoclopramide is excreted principally through the kidneys, leading to drug accumulation in renal impairment. 1

Pharmacokinetic Rationale

• Research demonstrates that creatinine clearance directly correlates with metoclopramide plasma clearance, renal clearance, nonrenal clearance, and elimination half-life. 2
• Importantly, even though renal clearance accounts for ≤21% of total plasma clearance regardless of renal function, nonrenal clearance is also reduced in patients with renal impairment, accounting for most of the reduction in total plasma clearance. 2
• The comparatively small plasma clearances in patients with renal dysfunction mean that maintenance doses must be reduced to avoid drug accumulation. 2

Practical Dosing Algorithm

Starting dose:

• Begin with 5 mg orally (or IV/IM if severe symptoms) for your patient with CrCl ~36 mL/min. 1
• Standard dosing for normal renal function is 10 mg, so this represents the mandated 50% reduction. 1

Frequency considerations:

• The standard frequency is typically every 6-8 hours for gastroparesis or other indications. 1
• With reduced clearance, consider starting at the lower frequency (every 8 hours) rather than every 6 hours. 2

Dose titration:

• Monitor clinical response and adverse effects (particularly extrapyramidal symptoms, which may be more common with accumulation). 1
• If inadequate response and no adverse effects, the dose may be cautiously increased, but avoid exceeding standard dosing without careful monitoring. 1

Critical Safety Considerations

• Hemodialysis does not significantly remove metoclopramide, so supplemental dosing after dialysis is unnecessary if the patient progresses to requiring dialysis. 2
• The elimination half-life is prolonged in renal impairment (baseline ~3.9 hours in patients with normal-to-mild impairment), necessitating dose reduction to prevent accumulation. 3
• Metoclopramide undergoes minimal hepatic metabolism except for simple conjugation, so hepatic impairment (if present) does not require additional dose adjustment beyond renal considerations. 1

Common Pitfall to Avoid

Do not use the standard 10 mg dose in this patient. The FDA label's threshold of CrCl <40 mL/min is absolute, and your patient's eGFR of 36.2 mL/min/1.73m² clearly falls below this threshold, mandating the 50% dose reduction from the outset. 1