| Antineovascularisation Agents | Not Available | 9 | 22 | Details |
| Antiobesity Preparations, Excl. Diet Products | Not Available | 18 | 103 | Details |
| Antioxidants | Naturally occurring or synthetic substances that inhibit or retard the oxidation of a s... more | 91 | 567 | Details |
| Antiparasitic Agents | Drugs used to treat or prevent parasitic infections. | 163 | 787 | Details |
| Antiparasitic Products, Insecticides and Repellents | Not Available | 116 | 652 | Details |
| Antiparasitics, ivermectin derivatives | Not Available | 0 | 0 | Details |
| Antiperspirants | Agents that are put on the SKIN to reduce SWEATING or prevent excess sweating (HYPERHID... more | 2 | 1 | Details |
| Antiplatelet agents | Drugs or agents which antagonize or impair any mechanism leading to blood platelet aggr... more | 71 | 313 | Details |
| Antiplatyhelmintic Agents | Agents used to treat cestode, trematode, or other flatworm infestations in man or animals. | 23 | 87 | Details |
| Antipropulsives | Not Available | 6 | 28 | Details |
| Antiprotozoals | Substances that are destructive to protozoans. | 123 | 665 | Details |
| Antiprotozoals, metronidazole derivatives | Not Available | 0 | 0 | Details |
| Antipruritics | Agents, usually topical, that relieve itching (pruritus). | 16 | 111 | Details |
| Antipruritics and Local Anesthetics | Not Available | 10 | 80 | Details |
| Antipruritics, Incl. Antihistamines, Anesthetics, Etc. | Not Available | 22 | 125 | Details |
| Antipsoriatics | Not Available | 15 | 66 | Details |
| Antipsoriatics for Systemic Use | Not Available | 5 | 27 | Details |
| Antipsoriatics for Topical Use | Not Available | 11 | 45 | Details |
| Antipsychotic Agents | Agents that control agitated psychotic behavior, alleviate acute psychotic states, redu... more | 105 | 920 | Details |
| Antipsychotic Agents (First Generation [Typical]) | Not Available | 21 | 251 | Details |
| Antipsychotic Agents (Second Generation [Atypical]) | Not Available | 23 | 436 | Details |
| Antipyretics | Drugs that are used to reduce body temperature in fever. | 4 | 59 | Details |
| Antirheumatic Agents | Drugs that are used to treat RHEUMATOID ARTHRITIS. | 197 | 1047 | Details |
| Antisense Elements (Genetics) | Nucleic acids which hybridize to complementary sequences in other target nucleic acids ... more | 19 | 35 | Details |
| Antisense Oligonucleotide Specific to the Antisense Transcript of UBE3A | Not Available | 1 | 0 | Details |