Table 6 Common pDDIs of prescriptions dispensed at SPC Anuradhapura 2015
Combination (%) | Mechanism of pDDI according to the Medscape drug interaction checker [21] |
|---|---|
Serious (Total = 94) | |
 Methotrexate-Leflunomide (6.4) | Leflunomide increases toxicity of methotrexate by pharmacodynamic synergism. |
 Meloxicam-Methotrexate (5.3) | Meloxicam increases levels of methotrexate by decreasing renal clearance. |
 Clopidogrel-Omeprazole (5.3) | Omeprazole decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. |
 Clopidogrel-Esomeprazole (5.3) | Esomeprazole decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. |
 Atorvastatin-Vitamin B3 (5.3) | Either increases toxicity of the other by pharmacodynamic synergism. |
 Atorvastatin-Fenofibrate (5.3) | Either increases effects of the other by pharmacodynamic synergism. |
Significant (Total = 1017) | |
 Aspirin-Losartan (5.5) | Aspirin decreases effects of losartan by pharmacodynamic antagonism. losartan and aspirin both increase serum potassium. |
 Losartan-Frusemide (3.2) | Losartan increases and furosemide decreases serum potassium. |
 Aspirin-Clopidogrel (3.0) | Either increases toxicity of the other by pharmacodynamic synergism. |
 Clopidogrel-Pantoprazole (2.3) | Pantoprazole decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. |
 Celecoxib-Diclofenac sodium (2.0) | Celecoxib and diclofenac both increase anticoagulation and serum potassium. |
 Aspirin-Frusemide (2.0) | Aspirin increases and furosemide decreases serum potassium. |
Minor (Total = 265) | |
 Glipizide - Sitagliptin (7.6) | Either increases effects of the other by pharmacodynamic synergism. |
 Metformin - Vitamin B12 (5.7) | Metformin decreases levels of cyanocobalamin by unspecified interaction mechanism. |
 Metformin-Frusemide (3.8) | Metformin decreases levels of furosemide by unspecified interaction mechanism. Furosemide increases levels of metformin by unspecified interaction mechanism. |
 Methotrexate - Folic acid (3.4) | Folic acid decreases effects of methotrexate by pharmacodynamic antagonism. |
 Aspirin-Diltiazem (2.6) | Diltiazem increases effects of aspirin by unknown mechanism. |
 Metformin-Hydrochlorothiazide (2.6) | Hydrochlorothiazide will increase the level or effect of metformin by basic (cationic) drug competition for renal tubular clearance. Hydrochlorothiazide decreases effects of metformin by pharmacodynamic antagonism. |