| Quinapril ACE Inhibitor Action Pathway |  | Drug Action | Glutamic acid / Quinapril / Zinc |
| Quinapril Action Pathway |  | Drug Action | Quinapril / Potassium cation / Zinc |
| Quinapril Metabolism Pathway |  | Drug Metabolism | Quinapril / Zinc |
| Quinethazone Action Pathway |  | Drug Action | Quinethazone / Potassium cation / Calcium |
| Quinethazone Action Pathway (old) |  | Drug Action | Cysteine / Quinethazone / Potassium cation / Urea |
| Quinidine Action Pathway |  | Drug Action | ATP / Quinidine / Potassium cation / Calcium |
| Quinidine Action Pathway (New) |  | Drug Action | Quinidine / Potassium cation / Calcium / Cyclic adenosine monophosphate |
| Quinidine barbiturate Action Pathway |  | Drug Action | Pyridoxal phosphate / Glutamic acid / ATP / Quinidine barbiturate / Calcium / Magnesium cation / Cyclic adenosine monophosphate / gamma-Aminobutyric acid / Pyrophosphoric acid |
| Quinidine barbiturate Drug Metabolism |  | Metabolic | Quinidine barbiturate |
| Quinine Action Pathway |  | Drug Action | ATP / Quinine / Mesoheme |
| Quinupristin Action Pathway |  | Drug Action | Quinupristin |
| Rabeprazole Action Pathway |  | Drug Action | ATP / Rabeprazole / Potassium cation / Zinc / Acetylcholine |
| Rabeprazole Antacid Action Pathway |  | Drug Action | Rabeprazole / Potassium cation / Zinc |
| Rabeprazole Metabolism Pathway |  | Drug Metabolism | Rabeprazole |
| Racepinephrine A1-Adrenergic Vasoconstriction Action Pathway |  | Drug Action | ATP / Epinephrine / Calcium / Magnesium cation |
| Racepinephrine B2-Adrenergic Bronchodilation Action Pathway |  | Drug Action | ATP / Epinephrine / Potassium cation / Calcium / Magnesium cation / Cyclic adenosine monophosphate |
| Raltegravir Action Pathway |  | Drug Action | Raltegravir |
| Raltegravir Drug Metabolism |  | Metabolic | Raltegravir |
| Raltitrexed Action Pathway |  | Drug Action | Tetrahydrofolic acid / Glutamic acid / NADH / Folic acid / ATP / Raltitrexed / Calcium / Magnesium cation / Formic acid / Deoxyuridine monophosphate |
| Ramelteon Drug Metabolism |  | Metabolic | Ramelteon |
| Ramipril ACE Inhibitor Action Pathway |  | Drug Action | Glutamic acid / Ramipril / Zinc |
| Ramipril Action Pathway |  | Drug Action | Ramipril / Potassium cation / Zinc |
| Ramipril Metabolism Pathway |  | Drug Metabolism | Ramipril / Zinc |
| Ramucirumab Action Pathway |  | Drug Action | Calcium / Ramucirumab |
| Ranitidine Action Pathway |  | Drug Action | ATP / Ranitidine / Potassium cation / Zinc / Acetylcholine |