Drug misuse - The risks of intravenous drug use

In the first of this new series looking at the management of patients who misuse drugs, Dr Meg Thomas identifies the specific health risks associated with drugs that are injected.

Intravenous drug users are prone to vein damage and infection
Intravenous drug users are prone to vein damage and infection

It is estimated that 0.4 per cent of the UK population currently injects illicit substances, mainly heroin and crack cocaine.1,2

Intravenous drug (IVD) use is clearly endemic in our society and all GPs will come into contact with users.

All illicit substances have risks. Use of the IV route is the greatest. IVD use causes a whole host of complications affecting a variety of different systems in the body. IVD users have a mortality risk up to 24 times that of the general population.3

IVD use is strongly linked with social deprivation, mental ill health and disadvantage in childhood.

This article will outline the specific risks. It will be followed up next week by an article focusing on the risk reduction strategies that GPs can easily incorporate into a 10-minute consultation.

The main risks of IVD use are dependency, damage to veins, infection and overdose.

The ICD10 definition of the dependence syndrome requires that three or more of the following have been present at some time in the past year:

  • a sense of compulsion to use the substance;
  • difficulties controlling use of the substance;
  • physiological withdrawal state;
  • tolerance;
  • neglect of other interests;
  • persistent use in spite of harmful effects.4

With dependency comes the risk of loss of stability in terms of work, housing and relationships. This can exacerbate the 'downward spiral' into escalating drug use and social exclusion.

Vein damage
Damage to veins is inevitable due to the repetitive nature of IVD use, poor technique, infection and irritation by noxious chemicals.

As veins are exhausted, more dangerous sites are used. Injecting into the femoral vein is very common and can cause deep vein thrombosis (DVT), septicaemia, arterial bleeding, neuropathic pain and ischaemia. Neck injecting is clearly dangerous because of the presence of major vessels, nerves, trachea and oesophagus. Mastitis is likely if breast veins are used. Penile veins are sometimes used by the desperate. This is an extremely dangerous practice with the risk of priapism.

Cocaine is a particularly risky drug in terms of vein damage. This is due to its local anaesthetic properties combined with the high frequency of injection.

In addition, the disinhibiting effect of the drug leads to a bravado approach where knowledge of safe injecting is ignored. Speedballing (injecting a crack/heroin mix) is widespread in some areas and also notorious for vein damage and subcutaneous infections. Temazepam is very damaging to veins.

Street drugs are 'cut' with all manner of irritant substances from bleach to talcum powder. Citrus acid is used in the injection process as a solvent and can also cause vein damage.

IVDU users face the risk of eventual loss of venous access for emergency situations.

The risks of infection are bacterial infection, blood-borne viral (BBV) infection or fungal infection.

Bacterial infection
Illicit drugs are not manufactured in sterile conditions. This leaves users vulnerable to pathogens, even when injection technique is perfect. The following problems often arise: abscesses; cellulitis; right-sided endocarditis (usually Staphylococcus aureus); septicaemia; tetanus and botulism.

There are about 100 cases of botulism in IVD users in the UK per year. It presents as a descending paralysis and can be fatal. The classic 'four Ds' symptoms comprise diplopia, dysphagia, dysarthria and dysphonia.

Blood-borne virus infection
Although rates of sharing of injecting equipment have dropped as a result of two decades of harm reduction strategies, a staggering 20 per cent of new users have hepatitis C.

Users still share injecting equipment, especially with sexual partners. The main blood-borne viruses of which we currently have knowledge are hepatitis C (HCV), hepatitis B (HBV) and HIV.

The prevalence of HCV in the general population lies between 0.4 and 1 per cent.

More than 90 per cent of people with HCV in the UK have injected drugs at some time in their lives. The major route of HCV transmission in the UK is by sharing drug injecting equipment. This is mainly via blood contaminated needles and syringes, although other paraphernalia such as spoons, water and filters may also be vehicles of infection.

Transmission by the sexual route is extremely low or even negligible. It only seems to occur during traumatic sex, particularly in people who are HIV positive.5,6 Fewer than 17 per cent of people with HCV have been diagnosed.5

HCV is extremely prevalent in IVD users. Rates vary between 30 and 80 per cent, and appear to be increasing.2

NICE guidance now advocates early treatment and treatment for all those who want it (including IVD users).5,7 However, only 1-2 per cent of those infected with HCV in the UK are receiving treatment.

The rate of HIV among injecting drug users in the UK used to be among the lowest in the world, with rates at around 1-3 per cent.2 Again, this was probably due to our long-term focus on harm reduction. However, there has been a recent increase in HIV infection rates, most significantly in London and particularly among homeless crack users.

One in six IVD users is infected with HBV.2 About 30 per cent of acute infections result in jaundice and many cases are not diagnosed. Only 66 per cent of IVD users have had HBV vaccine.

Fungal infection
Candida species are natural commensals in citrus fruit. Injecting acids such as lemon juice and vinegar can cause candidiasis, with complications such as candida endophthalmitis.

The UK has one of the highest rates of drug-related death due to overdose in Europe. Acute drug-related deaths accounted for more than 7 per cent of all deaths among those aged 15-39 years in 2004.8

The majority of these deaths were associated with injecting heroin in combination with other sedatives such as alcohol, benzodiazepines or other depressants. Risky times for death due to overdose are during induction into methadone treatment and following a period of abstinence (e.g. a spell in prison) due to loss of tolerance to the opioid.

Other problems
IVD users have a high risk of death from TB, smoking related diseases and alcohol-related problems. IVD use is dangerous and presents a significant challenge. GPs and other primary care staff are ideally placed to support, educate and treat their drug using patients.

  • Dr Thomas is a GP in Swindon


1. NICE. Public Health Guidance 18 - Needle and Syringe Programmes, London: NICE, February 2009.

2. Health Protection Agency. Shooting up. Infections among injecting drug users in the UK October 2008 (updated October 2009).

3. National Treatment Agency Drug Misuse and Dependence: UK Guidelines on Clinical Management. October 2007.

4. Ghodse H. Drugs and addictive behaviour - a guide to treatment. 2nd ed. Oxford: Blackwell Science, 1995.

5. Coffey E, Young D. Guidance for hepatitis A and B vaccination of drug users in primary care and criteria for audit. London: RCGP, 2005.

6. Vandelli C, Renzo F, Romano L et al. Lack of evidence of sexual transmission of hepatitis C among monogamous couples: results of a 10-year prospective follow-up study. Am J Gastroenterol 2004; 99(6): 855-9.

7. NICE. Technology Appraisal 106. Hepatitis C - peginterferon alfa and ribavirin. London: NICE, August 2006.

8. European Monitoring Centre for Drugs and Drug Addiction. Annual report 2006: State of the drugs problem in Europe. Available at www.emcdda.europa.eu/drug-situation

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