Harm reduction with syringe filters: an update on the evidence

Transcription

1 Harm reduction with syringe filters: an update on the evidence Huei Ng Rahul Patel Roger Latham Stuart McLean Raimondo Bruno School of Medicine University of Tasmania

2 Much of the harms from injection comes from non-drug contaminants Key contaminants Microorganisms (bacteria, fungi) Insoluble particles (environment, excipients) Effects Tissue & vein irritant (inflammation) Infections on skin/muscle injection (granuloma, abscesses) Local and systemic infection (bacteria & fungi) Undissolved particles Microcirculation: 5-10μm capilliaries Pulmonary circulation: μm arteries Granulomas in lungs Inflammation scar tissue (fibrosis) congmomerate masses restrictive lung disease & pulmonary hypertension Particulates also reach other organs (e.g. liver)

3 Common bacteria causing harms Staphylococcus aureus (SA) Streptococcus pyogenes (SP) Pseudomonas aeruginosa (PAO) Most common cause of soft tissue infections (abscesses, cellulitis) and more severe infections (endocarditis) often from consumers commensal flora

4 Examples of tablet excipients Talc Hypromellose Naturally occurring powder Tablet lubricant (1-10%) & diluent (5-30%) Typically: 99% <74um Will contain microorganisms Substantial evidence for accumulation in organs if IV Controlled-release coating agent (2-10%) Fibrous or granular powder Turns to gel (reversibly) at 50-90C

5 Methods Preparation Example: Neubauer blood counting slide (other lens contained scale) 4x magnification Drugs (MS Contin, OxyContin OC, subutex, suboxone strips) prepared following procedures reported by consumers Unfiltered and filtered using: cig filter; 0.45µm, 0.22µm, 0.8/0.2µm wheel filters Particle counting and sizing Light microscopy Samples from each preparation (x3) Counting from subtractive image Drug Recovery HPLC or spectrophotometry Bacteria Grown overnight on tryptone soy broth, with 1.5% agar, at 35 C, filtered with tablet

6 Examples of filtered solutions (OxyContin 80mg) unfiltered Cig. filtered rollie µm filtered rollie µm filtered

7 Examples of particle counts in unfiltered injections MS Contin tablet Subutex tablet

8 OxyContin (OC) Subutex Using a cigarette filter Unfiltered Unfiltered Filtered Filtered

9 How much do cigarette filters alone reduce particles?

10 OxyContin (OC) Subutex Using a cigarette filter, then a wheel filter Unfiltered Unfiltered Filtered D Filtered

11 How much do cigarette filters in conjunction with 0.45μm wheel filters reduce particles? Medical standard for safe solution for injection (British Pharmacopeia, 2005): no more than 3000 particles >10 µm; no more than 300 particles >25 µm

12 How much do cigarette filters in conjunction with 0.22μm wheel filters reduce particles? Medical standard for safe solution for injection (British Pharmacopeia, 2005): no more than 3000 particles >10 µm; no more than 300 particles >25 µm

13 What about the single device filter (0.8/0.2µm)? Medical standard for safe solution for injection (British Pharmacopeia, 2005): no more than 3000 particles >10 µm; no more than 300 particles >25 µm

14 Are filters still any good at removing bacteria when you push bacteria + tablets through? Substantially worse than 0.22 Both below limits of detection

15 Yes, but do you lose your drug?

16 Why not heating? B 100 μm Heating changes form of some excipients, if warm, these pass through filter and re-congeal. No benefits of heat compared with cold after filtering. C 100 um D 100 μm

17 Don t force it! 0.5/0.45 µm Excessive pressure Standard pressure <1min >3min

18 OP Oxycontin: What to do? Reformulation: harder to break, viscous gel when liquid added Citric? Risk of fungal infection What is in the end product? Internet recipes They exist, but What is in the end product? Are the excipients gone? Are there harm from added chemicals in workarounds? Stakes are high Risk of very significant venous harms Swallowing is safe(r)

19 Conclusions Not injecting is safest Cloudy problem particles Heating is misleading If been handled (or in mouth) definitely use a wheel filter - remove large bacteria (e.g. Staphylococcus aureus, Candida) Don t add excessive pressure Always swab to remove bacteria Good: Filter with a rollie filter at least (and rinse) ~>90% dose; ~60% problem particles Better: filter with rollie filter, rinse, then 0.22μm filter ~>90% dose; <95% particles; remove large bacteria More betterer: 0.8/0.2μm filter ~>90% dose; <95% particles; remove large bacteria Double filters need trialling (~$2/ea) Cost of hospital presentation: $3907 per avg admission (AG DHA, 2009) Estimated cost of treating IRID (exc. HIV/HCV) for Vic, NSW, Qld (community, ER, inpatient) $19m in 2005/06 (Dwyer et al, Burnett Inst, 2007)