| Paramagnetic Contrast Media | Not Available | 13 | 30 | Details |
| Parasympatholytics | Agents that inhibit the actions of the parasympathetic nervous system. The major group ... more | 47 | 157 | Details |
| Parasympathomemetic (Cholinergic) Agents | Not Available | 8 | 49 | Details |
| Parasympathomimetics | Drugs that mimic the effects of parasympathetic nervous system activity. Included here ... more | 19 | 96 | Details |
| Parathyroid Agents | Not Available | 1 | 2 | Details |
| Parathyroid and Antiparathyroid Agents | Not Available | 1 | 1 | Details |
| Parathyroid Hormone-Related Protein | Not Available | 1 | 1 | Details |
| Parathyroid Hormones and Analogues | Not Available | 5 | 7 | Details |
| Parenteral Iron Replacement | Not Available | 10 | 31 | Details |
| Parenteral Nutrition Solutions | Specialized solutions for PARENTERAL NUTRITION. They may contain a variety of MICRONUTR... more | 2 | 3 | Details |
| Partial Cholinergic Nicotinic Agonist | Not Available | 1 | 6 | Details |
| Partial Cholinergic Nicotinic Agonists | Not Available | 1 | 6 | Details |
| Partial Opioid Agonist/Antagonist | Not Available | 1 | 4 | Details |
| Particulate Matter | Particles of any solid substance, generally under 30 microns in size, often noted as PM... more | 2 | 1 | Details |
| Passively Acquired Immunity | Not Available | 12 | 16 | Details |
| PCSK9 Inhibitor | Agents that inhibit Proprotein Convertase Subtilisin/Kexin Type 9 (see PROPROTEIN CONVE... more | 5 | 5 | Details |
| PD-1/PD-L1 (Programmed cell death protein 1/death ligand 1) inhibitors | Not Available | 14 | 15 | Details |
| PD-1/PDL-1 (Programmed cell death protein 1/death ligand 1) inhibitors | Not Available | 10 | 11 | Details |
| Pedaliaceae | Not Available | 0 | 0 | Details |
| Pediculicides | Not Available | 4 | 28 | Details |
| Pegylated agents | Not Available | 41 | 73 | Details |
| Penem Antibacterial | Not Available | 5 | 45 | Details |
| Penicillamine and Similar Agents | Not Available | 2 | 4 | Details |
| Penicillin G | A penicillin derivative commonly used in the form of its sodium or potassium salts in t... more | 23 | 78 | Details |
| Penicillinase-resistant Penicillins | Not Available | 1 | 7 | Details |