| Abbreviation | Definition |
|---|---|
| HDAS | Hillingdon Drug Alcohol Services |
| HDAS | Hillingdon Drug and Alcohol Services |
| HDDD | Health Diagnostics and Drug Development |
| HDRA | Histoculture Drug Response Assay |
| HDRST | HIV Drug Resistance Surveillance Team |
| HDTNS | High Dose Topical Nasal Steroids |
| HFTB | Hits From The Bong |
| HIDTA | High Intensity Drug Traffic Area |
| HIDTA | High Intensity Drug Trafficking Areas |
| HPC | Hayat Pharma Canada |
| HRS | Harm Reduction Services |
| HSDO | Hypnotic Sedative Drug Overdosed |
| HSDP | Highly Specialised Drugs Program |
| HYDE | Hide Your Drugs Everyday |
| I | Iodine |
| IADAF | Israel Anti Drug Abuse Foundation |
| ICDP | Illinois Consortium on Drug Policy |
| ICDT | Inchicore Community Drug Team |
| ICP | Inhalation Capsules Production |
| ICS | Inhaled Corticosteroids |