| 5-HT1B receptor antagonists | Not Available | 0 | 0 | Details |
| Abortifacient Agents | Chemical substances that interrupt pregnancy after implantation. | 12 | 74 | Details |
| Abortifacient Agents, Nonsteroidal | Non-steroidal chemical compounds with abortifacient activity. | 8 | 56 | Details |
| Abortifacient Agents, Steroidal | Steroidal compounds with abortifacient activity. | 2 | 18 | Details |
| Acaricides | Not Available | 1 | 0 | Details |
| ACE Inhibitors and Calcium Channel Blockers | Not Available | 13 | 130 | Details |
| ACE Inhibitors and Diuretics | Not Available | 13 | 53 | Details |
| Acetal derivatives | Not Available | 0 | 0 | Details |
| Acetaldehyde | A colorless, flammable liquid used in the manufacture of acetic acid, perfumes, and fla... more | 1 | 1 | Details |
| Acetals | Not Available | 1 | 1 | Details |
| Acetamides | Derivatives of acetamide that are used as solvents, as mild irritants, and in organic s... more | 23 | 46 | Details |
| Acetaminophen and Prodrugs | Not Available | 2 | 41 | Details |
| Acetanilides | Compounds based on N-phenylacetamide, that are similar in structure to 2-PHENYLACETAMID... more | 7 | 34 | Details |
| Acetates | Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid for... more | 77 | 285 | Details |
| Acetic Acid Derivatives and Related Substances | Not Available | 17 | 110 | Details |
| Acetophenones | Derivatives of the simplest aromatic ketone acetophenone (of general formula C6H5C(O)CH3). | 1 | 0 | Details |
| Acetyl Aldehyde Dehydrogenase Inhibitors | Not Available | 1 | 6 | Details |
| Acetylcholine Release Inhibitors | Compounds that block release of the neurotransmitter ACETYLCHOLINE. | 2 | 6 | Details |
| Acetylcholine Releasing Agent | Not Available | 1 | 15 | Details |
| Acetylcholine, secretion | Not Available | 0 | 0 | Details |
| Acetylcholinesterase inhibitors, Tacrine and derivatives | Not Available | 0 | 0 | Details |
| Acid Anhydride Hydrolases | A group of enzymes that catalyze the hydrolysis of diphosphate bonds in compounds such ... more | 1 | 0 | Details |
| Acid Etching, Dental | Not Available | 2 | 5 | Details |
| Acid Preparations | Not Available | 4 | 121 | Details |
| Acid Reducers | Drugs which actively reduce the hydronium concentration of the gastric system. Includes... more | 18 | 195 | Details |