| Retinol Metabolism |  | Metabolic | NADH / Vitamin A / Alitretinoin / Tretinoin / Iron / Zinc / Mesoheme / 4-Oxoretinol |
| Reviparin Action Pathway |  | Drug Action | Calcium / Reviparin |
| Ribavirin Action Pathway |  | Drug Action | Ribavirin / Calcium / Magnesium cation |
| Ribavirin Drug Metabolism |  | Metabolic | Ribavirin |
| Riboflavin Drug Metabolism |  | Metabolic | Riboflavin |
| Riboflavin Metabolism |  | Metabolic | Adenosine phosphate / Riboflavin / ATP / Calcium / Magnesium cation / Zinc / Flavin adenine dinucleotide / Flavin mononucleotide / Pyrophosphoric acid |
| Ribose-5-phosphate Isomerase Deficiency |  | Disease | Adenosine phosphate / ATP / Magnesium cation / Iron / 5-O-phosphono-alpha-D-ribofuranosyl diphosphate / D-glyceraldehyde 3-phosphate / Ribose-1-Phosphate / Ribulose-5-Phosphate / Dihydroxyacetone phosphate / Gluconolactone |
| Ribose-5-phosphate Isomerase Deficiency |  | Disease | Adenosine phosphate / ATP / Magnesium cation / Iron / 5-O-phosphono-alpha-D-ribofuranosyl diphosphate / D-glyceraldehyde 3-phosphate / Ribose-1-Phosphate / Ribulose-5-Phosphate / Dihydroxyacetone phosphate / Gluconolactone |
| Rilmenidine Drug Metabolism |  | Metabolic | Rilmenidine |
| Rilpivirine Action Pathway |  | Drug Action | Rilpivirine |
| Riluzole Predicted Metabolism Pathway |  | Metabolic | Riluzole / Mesoheme |
| Rimantadine Action Pathway |  | Drug Action | Rimantadine / Calcium |
| Rimantadine Drug Metabolism |  | Metabolic | Rimantadine |
| Rimexolone Action Pathway |  | Drug Action | Glutathione / Rimexolone / Dinoprostone / Calcium / Prostaglandin D2 / Mesoheme / Prostaglandin G2 / Arachidonic Acid |
| Rimonabant Drug Metabolism |  | Metabolic | Rimonabant |
| Ripretinib Action Pathway |  | Drug Action | Calcium / Ripretinib |
| Ripretinib Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Ripretinib |
| Risedronate Action Pathway |  | Drug Action | Cholecalciferol / ATP / Risedronic acid / Magnesium cation / Iron / Dimethylallyl Diphosphate / Formic acid / Geranyl Diphosphate / Mesoheme / Flavin adenine dinucleotide / Palmitic Acid / Pyrophosphoric acid / Cholesterol / ISOPENTENYL PYROPHOSPHATE / Farnesyl diphosphate |
| Risedronate Action Pathway (new) |  | Drug Action | ATP / Risedronic acid / Magnesium cation / Dimethylallyl Diphosphate / Geranyl Diphosphate / Pyrophosphoric acid / Cholesterol / ISOPENTENYL PYROPHOSPHATE / Farnesyl diphosphate |
| Risedronate Drug Metabolism Pathway |  | Metabolic | Risedronic acid |
| Risperidone Dopamine Antagonist Action Pathway |  | Drug Action | Pyridoxal phosphate / Tyrosine / Sapropterin / Risperidone / Dopamine / Levodopa / Paliperidone / Calcium / Iron / Mesoheme |
| Risperidone Serotonin Antagonist Action Pathway |  | Drug Action | Pyridoxal phosphate / Tryptophan / Sapropterin / Risperidone / Paliperidone / Calcium / Iron / Mesoheme / Oxitriptan |
| Ritiometan Drug Metabolism |  | Metabolic | Ritiometan |
| Ritodrine B2-Adrenergic Myometrial Smooth Muscle Relaxation Action Pathway |  | Drug Action | ATP / Ritodrine / Potassium cation / Calcium / Magnesium cation / Cyclic adenosine monophosphate |
| Ritonavir Action Pathway |  | Drug Action | Ritonavir / Magnesium cation |