Table 1 Drug-lab interaction guidelines for a sample of our selected high-volume medications
Medication a | ATC category and name b | Dose adjustment in renal impairment | Dose adjustment in hepatic impairment | Pregnancy considerations | Lab monitoring considerations | |
|---|---|---|---|---|---|---|
1 | Allopurinol | M04: ANTIGOUT PREPARATIONS | • 10 ≤ CrCl < 20 ml/min/1.73m2: prescribe 200 mg/day per oral • 3 ≤ CrCl < 10 ml/min/1.73m2: prescribe 100 mg/day per oral • CrCl < 3 ml/min/1.73m2: prescribe 100 mg per oral every 24 h or longer; or 100 mg per oral every third day. | Dosage adjustment may be necessary; No specific recommendations available | – | Monitor Uric acid level: • If normal, check it every 6 months. • If abnormal, change Allopurinol dose accordingly |
2 | Azathioprine | L04: IMMUNOSUPPRESSANTS | • If renal impairment or oliguria exists, then dosage should be modified depending on clinical response and degree of renal impairment. No quantitative recommendations are available. | Specific guidelines for dosage adjustments in hepatic impairment are not available | Discontinue | – |
3 | Captopril | C09: AGENTS ACTING ON THE RENIN-ANGIOTENSIN SYSTEM | • 10 ≤ CrCl < 50 ml/min/1.73 m2: reduce the recommended dose by 25%. • CrCl < 10 ml/min/1.73 m2: reduce the recommended dose by 50%. | No adjustment is required | Discontinue | Monitor Na and K at the baseline and 1–2 weeks after the start. |
4 | Cyclosporine | L04: IMMUNOSUPPRESSANTS | No adjustment is required | • In hepatic impairment (ALT > 40 U/mL OR AST > 40 U/L OR Bili-total > 1.5 mg/dl): monitor Cyclosporine blood concentration level. May require dose reduction based on concentration. | – | Monitor Uric acid, K, and Mg levels every 2 weeks in the first 3 months then monthly |
5 | Hydrochlorothiazide | C03: DIURETICS | • CrCl < 30 ml/min/1.73 m2: do not use. | • In hepatic impairment (ALT > 40 U/mL OR AST > 40 U/L OR Bili-total > 1.5 mg/dl): use with caution, since minor alteration of fluid and electrolyte balance may precipitate hepatic coma. | – | Monitor K, Na and Cl |
6 | Losartan | C09: AGENTS ACTING ON THE RENIN-ANGIOTENSIN SYSTEM | • CrCl < 30 ml /min/1.73m2: If the patient is also volume-depleted, dose adjustment will be needed. | • In hepatic impairment (ALT > 40 U/mL OR AST > 40 U/L OR Bili-total > 1.5 mg/d): initiate with 25 mg per oral once daily. | Discontinue | Monitor Na and K at the baseline and 1–2 weeks after the start |
7 | Mycophenolat (mycophenolic acid) | L04: IMMUNOSUPPRESSANTS | • CrCl < 25 ml/min/1.73 m2: do not exceed 1 g per oral twice daily. | No adjustment is required | Discontinue | Monitor pregnancy test |
8 | Omeprazole | A02: DRUGS FOR ACID RELATED DISORDERS | No adjustment is required | • In severe hepatic disease (AST > 120 U/L OR ALT > 120 U/ml OR Bili-total > 3 mg/d) and cirrhotic liver disease: reduce Omeprazole dose to 10 mg once daily receiving for long-term therapy. | – | Monitor Mg and Vit B12 levels periodically |