Comparison of heroin and hydromorphone in opioid users

Hydromorphone (HM) is a potential alternative to heroin (H) in opioid dependence prescription trials. A within‐subject study of 8 casual injection heroin‐users compared acute intravenous (iv) and subcutaneous (sc) H and HM effects over a range of 4 doses to determine if they are pharmacologically distinguishable. Subjective, physiological, and behavioral measures were assessed before and for 3 hours after administration. Comparing baseline‐corrected peak values (highest doses, HM 2.5 mg iv (A) vs H 10 mg iv (B) and HM 5 mg sc (C) vs H 20 mg sc (D)), pupil diameter mean reductions (mm) were −3.19 (A) vs −3.34 (B) & −3.30 (C) vs −3.35 (D). Decreases in mean % oxygen saturation levels were −2.4 for iv doses (A & B) & for sc doses −1.6 (C) vs −2.1 (D). Visual analog scales ratings (0‐100) for a “Drug Effect” were 66.8 (A) vs 66.9 (B) & 70.5 (C) vs 63.8 (D), and for a “Rush” were 70.8 (A) vs 65.6 (B) & 52.6 (C) vs 58.5 (D). Opiate adjective scores of weighted Fraser scale agonist effects were 8.1 (A) vs 9.4 (B) & 12.4 (C) vs 13.8 (D). H and HM produced similar effects, had similar time courses, peak effect times, onsets of action, and approximately parallel dose response curves on most measures, with HM being 3–4 fold more potent than H. Subjects only subjectively distinguished the effects of iv H from iv HM: heroin identifications (mean % correct responses/session, all doses) are 70.3% vs 69.5% (iv) (NS) & 54.7% vs 78.1% (sc) (p<.001). HM may be a suitable surrogate for heroin. Clinical Pharmacology & Therapeutics (2004) 75 , P3–P3; doi: 10.1016/j.clpt.2003.11.008