Filtering licit and illicit drugs for injecting

Discussion in 'The euphoric body' started by Lunar Loops, Jul 18, 2006.

  1. Lunar Loops

    Lunar Loops Driftwood Platinum Member & Advisor

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    Feb 10, 2006
    from ireland
    SWIS wasn't quite sure which section to post this in, but thought it was of a general enough nature to be posted here. It is of no actual use to SWIS, but SWIS thought it may, or may not, be useful to other yous out there. The article comes from Druginfo Clearinghouse ( :

    Number FS.5 July 2006
    for workers and people who inject drugs
    by Sarah Lord and Damon Brogan, VIVAIDS Inc.

    Our bodies have a number of natural defences that protect us from disease and other infections. When we inject drugs into our body we bypass the main natural defence system: our skin. This leaves us vulnerable to nasty infections and diseases from bacteria, fungi and viruses, including HIV (Human Immunodeficiency Virus), hepatitis B and hepatitis C.
    This fact sheet provides information on filters, filtering and reducing the harms associated with injecting drug use. It is written for people who are injecting drugs and the service providers who work with them.
    All drugs have harms associated with them. Injecting drugs, especially outside the medical setting, carries an increased risk of harms such as overdose, vascular damage, infection and the transmission of blood-borne viruses.
    This fact sheet is not meant to be a substitute for professional advice. Talk to an alcohol and other drug worker, your local user group, needle and syringe program worker, your doctor or other health professional if you have any problems or concerns about drug-related harms.​
    Why filter?

    Injectable drugs used by medical practitioners are prepared in sterile laboratories, stored in sterile packaging and usually administered to the patient in a clinical environment. Illicit, injectable drugs are not produced, stored or consumed in such environments, and can be full of germs and harmful particles.
    Some people inject tablets or pills containing drugs such as morphine and benzodiazepines. These preparations are made for oral consumption and contain ingredients that do not easily break down in water and may cause damage if injected. These insoluble particles can block small blood vessels, thereby cutting off oxygen flow to tissues in the body. Cells deprived of adequate blood flow will die and rot. Insoluble particles can also result in harmful deposits in the larger blood vessels, eyes, lungs and other organs.
    In addition, when preparing these drugs for injection, microbes, (infection-causing agents) from the surface of the tablets/pills, from the air or from the hands or other surfaces can get into the mix (solution) and thereby into the bloodstream. You will not be able to see these microbes, but they can be present in the millions and they can cause very serious infections when injected via a contaminated drug mix.​
    Reducing harms

    Filtering helps to remove most of the insoluble particles that can cause damage if injected. Some materials and techniques used for filtering drugs can greatly reduce the chance of bacterial and fungal infections. How you filter and what you use for a filter depends on a range of factors, some of which are addressed in the basic guide to filters below.
    It is important to note that no filter can remove a virus. The only way to reduce the chance of introducing a virus into your body is to understand blood-borne virus prevention strategies and to use this knowledge when preparing drugs for intravenous use.​
    Types of filters

    Handmade filters

    The most common types of filters used by people who inject are cotton wool, tampons, cigarette filters and swabs (for example, alco-wipes). These materials all provide a basic level of filtering; they remove many of the larger insoluble particles and they are also useful in drawing up drug mixes from spoons and in helping to preserve a sharp needle point.
    But handmade filters from these materials also have inherent problems and limitations:​
    • Because they have to be manipuated by hand, there is a greater chance of bacterial contamination and virus transmission, where there might be traces of blood on the fingers.​
    • They are not efficient in removing large amounts of insoluble material, as with crushed tablets.​
    • If they are stored for re-use, dangerous amounts of bacteria and fungi can grow on them.​
    • If used filters are passed from one person to another for re-use, there is more potential for blood-borne viruses to be transmitted. Cotton filters, in particular, can hold residual quantities of drugs after use, so there is more potential for storage, re-use and passing on to others.​
    Cotton filters

    In addtion to the problems listed above, cotton has been associated with "cotton fever". This is caused by a bacterial agent. Cotton wool and cotton buds are not produced, treated or packaged for clinical use, so there is still a risk of cotton fever and other infections when used in the preparation of solutions for injecting.​
    Cigarette filters

    Cigarette filters can contain harmful chemicals and very small fibres that can break off and end up being injected into the body.​

    Swabs are very thin and do not provide good protection to the delicate needle tip; blunt needles cause vein damage. When used correctly, swabs are very useful in cleaning your fingers and injecting sites, but it is very important to understand that the isopropyl alcohol in medi-swabs (alco-wipes etc) will not sterilise or even clean a drug mix. Isopropyl alcohol is not really suitable for internal use and there may be health risks associated with prolonged use.​
    Wheel filters and Sterifilt®

    Filters that come in individual, sterile packages are generally safer to use compared to those that are not. Also, any filter that can be used without touching the filter membrane (such as wheel filters and Sterifilt®) is safer in terms of reducing contamination that can cause infections and "dirty hits", compared to those where the filter is formed by hand and finger manipulation such as cotton wool, pieces of cigarette filter and swabs.​
    Filter sizes

    Different filters will filter drugs to different degrees. The filter that has the smallest pores (holes) will give a greater degree of filtration, compared to a filter with a larger pore size. Filter pores are generally measured in microns (one thousandth of a millimetre, µ). There is no filter that can remove a virus. The only filters able to remove all bacteria are 0.22µ and smaller (that is, 0.1µ–0.22µ). Nearly all common bacteria are larger than 0.22µ, so it will be retained by this size filter. A filter larger than 0.22µ is mainly used to remove particulate matter (for example bits of dirt/dust). The largest filter usually stocked by needle and syringe programs is 5µ and the smallest is most often 0.22µ. See the the basic guide to filters below for the various qualities and uses of the different filter types.
    Sometimes pre-filtering with a larger-sized filter before using a smaller filter is needed to remove particulate matter from the mix. A large quantity of starch or chalk from a crushed tablet could easily block a 0.22µ bacteria filter, so it makes sense to pre-filter with a 5µ wheel filter or Sterifilt® to remove the larger particles first.​
    Other factors to consider

    It is worth remembering that you may not always have the best option for filtering at your disposal. The filters available at any time depend on many factors such as:​
    • cost of filters (wheel filters, Sterifilt®, cotton wool and other filters vary in price)​
    • access to filtering equipment (not all needle and syringe programs stock all filters)​
    • knowledge and information (Do you have the "know-how" to use wheel filters or Sterifilts®?)​
    • setting (where you inject: home, car, squat, laneway etc.)​
    • social context (who else is around when preparing and injecting drugs)​
    • drug type (for example, some drugs need more filtering than others)​
    • ease of use (some filters are easier and faster compared to others).​
    Filters should never be re-used. Any filter (especially a wheel filter, in which the filter membrane is enclosed inside plastic casing) is likely to grow mould and bacteria after being used. Cotton, cigarette filters and swabs will be damp after use, leaving them vulnerable to picking up dirt and bacteria. Bacteria will start to grow inside a filter and, if re-used, increases the chances of getting a "dirty hit", or worse.
    The less a filter is manipulated by your fingers, the cleaner it is likely to be. This means less dirt and germs in your mix.​
    Basic guide to filters

    Below is a basic guide to filters for people who inject dugs. The filters are ranked from the most to least safe, based on the pore size of the filter unit. This guide has been designed to help you make safer, more informed choices about how to filter a range of substances.
    Filter typeFilter sizeDrugs used withTipsBacterial wheel filter0.22µBuprenorphine
    Methamphetamine (speed)
    • This filter type provides the highest level of filtration and works well as long as the drug solution (mix), is not too "gluggy".
    • Buprenorphine usually requires pre-filtering with a 5µ or 1.2µ filter.
    Other wheel filters0.45µ –1.25µ Buprenorphine
    Morphine pills
    • If you are mixing up more than one pill you may need to use a 1.25µ or a 5µ filter first.​
    • If a pill has been inside someone's mouth you must use a 0.22µ bacterial wheel filter before injecting, to remove bacteria and fungi.​
    Largest wheel filter5µReally gluggy mixes, large quantities of most pills and pre-filtering
    • If a pill has been inside someone's mouth you can remove fungi and bacteria by using a 0.22µ bacterial wheel filter after the 5µ filter.
    Sterifilt® filterAmphetamines (especially "bag" mixes)
    Most pills
    • As above
    Cotton wool from tampon and sterile cotton wool balls (sterile until opened) About 50µ when rolled upCocaine
    Methamphetamine (speed)
    Pills (for pre-filtering only)
    • Wash hands and arms in warm soapy water, and swab fingers before making filter.​
    • Cover tampon with cling wrap in between uses to prevent contamination.​
    Cotton wool ball/cotton bud (not sterile) About 50µ when rolled upAs above
    • As above
    Rollie cigarette filter (no fibre glass; not sterile)About 50µ when rolled upAs above
    • As above
    Piece of swab (sterile until opened)About 50µAs above
    • Isopropyl alcohol is not meant to be injected.
    • It is easy to blunt the needle on the base of a spoon.
    • Requires some finger manipulation to make this filter.
    Cigarette filter (contains fibre particles; not sterile)About 50µAs above
    • They contain harmful fibre particles that can lodge in body tissue.
    • Never use a cigarette that has been smoked, as you are almost guaranteed to get a "dirty hit".
    No filterNo filteringAny drug
    • Most dangerous option because there is no "filter membrane" between the bacteria and dirt and your blood stream.
    More information

    For more information on safer injecting, see The Safer Injecting Handbook, 3rd edition, available from the Australian Drug Foundation, tel. 1300 85 85 84 or online at, or contact VIVAIDS on tel. (03) 9329 1500 or your local drug user organisation.
    For more information on drugs and drug prevention contact the DrugInfo Clearinghouse on tel. 1300 85 85 84, email [email protected], or visit our website​
    Suggested citation

    "Filtering licit and illicit drugs for injecting", by Sarah Lord and Damon Brogan, VIVAIDS Inc., Fact sheet no. FS.5, July 2006, published by DrugInfo Clearinghouse, Australian Drug Foundation, available online at
    Last edited by a moderator: Sep 10, 2017
  2. old hippie 56

    old hippie 56 Gold Member

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    May 10, 2005
    Wish I had this info years ago, it would have saved him alot of trouble.
  3. cra$h

    cra$h Palladium Member

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    Oct 21, 2007
    from Philly
    Swim hates sounding dumb, and naive, and understands the whole reason to why the filters are used, but lets say a cotton ball is used, how exactly is this done? is it just:

    1. put cotton ball in spoon, on top of dope
    2. stick needle partway into the cotton ball?, and plunge up?

    so what swim's trying to get at, in summary, is how deep should the needle be into the filter, to be safe, as efficientcy isn't the primary concern.
  4. old hippie 56

    old hippie 56 Gold Member

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    May 10, 2005
    Right under the surface on the top. Don't pull the plunger back fast, take it slow to cut back on air intake.
  5. cra$h

    cra$h Palladium Member

    Reputation Points:
    Oct 21, 2007
    from Philly
    ah, perfect! Couldn't ask for anything right to the point, and of course the whole procedure will be executed extremely slow. Now to find a needle.....