| Pilocarpine M2 Ciliary Muscle Contraction Action Pathway |  | Drug Action | ATP / Pilocarpine / Potassium cation / Calcium / Magnesium cation / Cyclic adenosine monophosphate |
| Pilocarpine M3 Iris Sphincter Muscle Constriction Action Pathway |  | Drug Action | Pilocarpine / Calcium / Magnesium cation |
| Pimethixene Drug Metabolism |  | Metabolic | Pimethixene |
| Pimethixene H1-Antihistamine Action |  | Drug Action | Calcium / Pimethixene |
| Pimozide Mechanism of Action Action Pathway |  | Drug Action | Pyridoxal phosphate / Tyrosine / Sapropterin / Dopamine / Pimozide / Levodopa / Calcium / Iron |
| Pinacidil Drug Metabolism |  | Metabolic | Pinacidil |
| Pinaverium Action Pathway |  | Drug Action | ATP / Calcium / Magnesium cation / Pinaverium |
| Pinaverium Drug Metabolism |  | Metabolic | Pinaverium |
| Pindolol Action Pathway |  | Drug Action | ATP / Pindolol / Potassium cation / Calcium |
| Pindolol B1-Adrenergic Cardiac Muscle Relaxation Action Pathway |  | Drug Action | ATP / Pindolol / Calcium |
| Pindolol B2-Adrenergic Vasodilation Action Pathway |  | Drug Action | ATP / Pindolol / Potassium cation / Calcium / Magnesium cation / Cyclic adenosine monophosphate |
| Pipotiazine Dopamine Antagonist Action Pathway |  | Drug Action | Pyridoxal phosphate / Tyrosine / Sapropterin / Dopamine / Levodopa / Calcium / Iron / Pipotiazine |
| Pipotiazine Predicted Metabolism Pathway |  | Metabolic | Pipotiazine / Mesoheme |
| Pipotiazine Serotonin antagonist Action Pathway |  | Drug Action | Pyridoxal phosphate / Tryptophan / Sapropterin / Calcium / Iron / Pipotiazine / Oxitriptan |
| Pipradrol Drug Metabolism |  | Metabolic | Pipradrol |
| Piracetam Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Piracetam |
| Pirbuterol Action Pathway |  | Drug Action | ATP / Pirbuterol / Potassium cation / Calcium / Magnesium cation / Cyclic adenosine monophosphate |
| Pirbuterol Drug Metabolism |  | Metabolic | Pirbuterol |
| Pirenzepine Action Pathway |  | Drug Action | ATP / Pirenzepine / Potassium cation / Zinc / Acetylcholine |
| Pirenzepine M1 Ulcer Treatment Action Pathway |  | Drug Action | Pirenzepine / Potassium cation / Zinc / Acetylcholine |
| Pirfenidone Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Pirfenidone |
| Piritramide Opioid Agonist Action Pathway |  | Drug Action | ATP / Calcium / Magnesium cation / Cyclic adenosine monophosphate / gamma-Aminobutyric acid / Pyrophosphoric acid / Sar9, Met (O2)11-Substance P |
| Piritramide Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Piritramide |
| Piroxicam Action Pathway |  | Drug Action | Glutamic acid / Glutathione / Piroxicam / Dinoprostone / Calcium / Magnesium cation / Zinc / Prostaglandin D2 / Mesoheme / Prostaglandin G2 / Arachidonic Acid |
| Piroxicam NSAID Action Pathway |  | Drug Action | Glutathione / Piroxicam / Dinoprostone / Calcium / Mesoheme / Prostaglandin G2 / Arachidonic Acid |