| Nortriptyline Action Pathway |  | Drug Action | Pyridoxal phosphate / Ascorbic acid / Tyrosine / Tryptophan / Sapropterin / Norepinephrine / Nortriptyline / Dopamine / Levodopa / Calcium / Iron / Oxitriptan / Pyrroloquinoline Quinone |
| Nortriptyline Predicted Metabolism Pathway |  | Metabolic | Nortriptyline / Mesoheme |
| Novobiocin Predicted Metabolism Pathway |  | Metabolic | Novobiocin / Mesoheme |
| Noxytiolin Drug Metabolism |  | Metabolic | Noxytiolin |
| Nucleotide Sugars Metabolism |  | Metabolic | NADH / ATP / Magnesium cation / Iron / Zinc / Uridine diphosphate glucose / Alpha-D-Galactose-1-Phosphate / Pyrophosphoric acid |
| Nylidrin Action Pathway |  | Drug Action | ATP / Potassium cation / Calcium / Magnesium cation / Cyclic adenosine monophosphate / Nylidrin |
| Nystatin Action Pathway |  | Drug Action | Nystatin / Ergosterol |
| Oftasceine Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Oftasceine |
| Olanzapine Dopamine Antagonist Action Pathway |  | Drug Action | Pyridoxal phosphate / Tyrosine / Olanzapine / Sapropterin / Dopamine / Levodopa / Calcium / Iron |
| Olanzapine H1 Antihistamine Neurological Sleep Action Pathway |  | Drug Action | Pyridoxal phosphate / Histidine / Olanzapine / Calcium |
| Olanzapine H1 Antihistamine Smooth Muscle Relaxation Action Pathway |  | Drug Action | Olanzapine / Calcium / Magnesium cation |
| Olanzapine H1-Antihistamine Blood Vessel Constriction Action Pathway |  | Drug Action | Arginine / Citrulline / Olanzapine / Sapropterin / Nitric Oxide / Calcium / Magnesium cation / Mesoheme / Flavin adenine dinucleotide / Flavin mononucleotide |
| Olanzapine H1-Antihistamine Immune Response Action Pathway |  | Drug Action | Olanzapine / Calcium |
| Olanzapine Serotonin Antagonist Action Pathway |  | Drug Action | Pyridoxal phosphate / Tryptophan / Olanzapine / Sapropterin / Calcium / Iron / Oxitriptan |
| Olaparib Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Olaparib |
| Olfactory Transduction OR1C1 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate |
| Olfactory Transduction OR1E3 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate / Acetophenone |
| Olfactory Transduction OR1L3 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate |
| Olfactory Transduction OR2AG1 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate |
| Olfactory Transduction OR2J3 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate |
| Olfactory Transduction OR2W1 |  | Physiological | ATP / Calcium / Cyclohexanone / Cyclic adenosine monophosphate |
| Olfactory Transduction OR5A1 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate |
| Olfactory Transduction OR5AC2 |  | Physiological | ATP / Calcium / Cyclic adenosine monophosphate |
| Oliceridine Opioid Agonist Action Pathway |  | Drug Action | ATP / Calcium / Magnesium cation / Cyclic adenosine monophosphate / gamma-Aminobutyric acid / Pyrophosphoric acid / Sar9, Met (O2)11-Substance P / Oliceridine |
| Oliceridine Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Oliceridine |