Many drugs are eliminated renally and dosing adjustments are needed in patients with acute kidney impairment or CKD. In CPJE exam, being able to recognize drugs that do NOT require dosing adjustments is useful in eliminating answer choice(s) or recognizing the correct answer choice(s). See table below for some common drugs that do not require renal dose adjustments.
|"NO RENAL DOSE ADJUSTMENT NEEDED" DRUGS |
Azithromycin (Zithromax®), Erythromycin
Dicloxacillin (Vibramycin®), nafcillin, oxacillin
Doxycycline, minocycline, tigecycline
Linezolid (Zyvox®), tedizolid
Metronidazole (Flagyl®), tinidazole
Vancomycin (PO only)
Metoprolol succinate (Lopressor®)
Metoprolol tartrate (Toprol®)
This table provides lab monitoring for common medications used in adults. Recommendations are made in FDA-approved labeling (i.e. package insert), except for recommendations in italic texts, which may differ from the product labeling. Label recommendations may be different among brand-name drugs or drugs within the same class.
|DRUG/DRUG CLASS ||LAB TEST ||INDICATION/FREQUENCY FOR TEST ||REASON FOR TEST ||NOTES |
|Aldosterone antagonists (i.e. spironolactone, eplerenone) ||Potassium & renal function || |
Guidelines: Check K+ and renal function at baseline, 3-7 days after initiation, monthly for 3 months, then quarterly. Restart monitoring cycle if ACEI or ARB added or its dose increased
Spironolactone: Check K+ and creatinine 1 week after initiation or dose increased, monthly for 3 months, quarterly for 1 year, then every 6 months
Eplerenone: Check K+ at baseline, within the 1st week, 1 month after initiation or dose adjustment, then periodically. If starting on moderate CYP3A4 inhibitors (i.e. azoles, clarithromycin, verapamil), check K+ and SCr within 3-7 daysm
|Hyperkalemia and worsened renal function caused by aldosterone antagonists || |
Spironolactone: HOLD or STOP If K+ > 5 mEq/L or SCr > 4 mg/dL
Eplerenone: DO NOT start if K+ > 5.5 mEq/L. HOLD or REDUCE if K+ is 5.5 mEq/L. For hypertension indication, do not start if SCr > 2 mg/dL in men or > 1.8 mg/dL in women or CrCl < 50 mL/min
|ACEI or ARB ||Potassium & renal function |
Check K+ and SCr within 1-2 weeks of initiation and after dose increased, then in 3-4 weeks if stable. Check again in 2-3 weeks if SCr increases. Then check once or twice a year, and when patient condition or medications change
Low risk patient with serum K+ 4.5 mEq/L or less: can check 4
ACEI or ARB: Monitor K+ frequently if concomitant use with K+ or K+ sparing ...