Cocaine Addiction and Abuse

Whether they have a special interest or not, GPs need to become familiar with the primary care management of drug abuse and in particular the main classes of drugs that are available. Although heroin is the commonest-used class A drug, cocaine addiction is on the increase.¹ This is in part due to the dropping price of the drug and the increasing availability of crack cocaine.²

• Cocaine hydrochloride powder is usually snorted but sometimes injected.
• Crack cocaine is the more volatile base form produced by heating the imported hydrochloride powder with sodium bicarbonate (baking soda) and water. It is usually smoked but sometimes injected. Processing cocaine in this way produces methylbenzoylecgonine (freebase cocaine) which crosses the blood-brain barrier faster and leads to the most serious problems.
• Cocaine is occasionally injected in combination with heroin. This is known as speedballing, and carries an increased risk of overdose.

Frequency of use can lead to different clinical effects. Three patterns of use have been identified:

• Recreational user - occasional use produces euphoria, increased alertness and feelings of self-confidence and competence.This is more pronounced when smoked or injected IV than when powder snorted. The 'high' is followed by a plateau and then a 'come down'.
• Binge user - frequent repeated use causes tachycardia, twitching, insomnia and anxiety. The patient may experience hallucinations or persecutory delusions that can result in dangerous aggression. Prolonged binges can result in a washed out syndrome: lethargy and deep sleep for several hours to days with spontaneous recovery.
• Chronic high dose dependency - can result in a perforated nasal septum, severe psychiatric and medical complications and fatalities (see below).

One study found that cocaine users had a moderate pattern of use (in terms of number of days use per month) compared with heroin users.⁴

Prevalence

According to a Home Office survey, cocaine use in the 16-24 year age group rose significantly between the years 1994 and 2000.^1,5 Use is increasing among young; in 2000, 5% of people in England and Wales aged of 16-29 years took cocaine at some time during the previous 12 months (1% in 1996).² Home Office statistics released in December 2005 showed a 16% increase in total cocaine-related offences in England and Wales compared to the previous year and an 8% increase in crack cocaine offences.⁶

Data released by the NHS Information Centre for the year 2006-2007 showed that 2.6% of adults reported taking cocaine, an estimated 835 000 people. This is an increase of 0.2% from the previous year and a 2% rise since 1996 and must be taken in context against a background of a reduction in use of other drugs, particularly cannabis.⁷

One review of information from official UK sources found that 1022 deaths from any cause were recorded in which the presence of cocaine or crack cocaine was mentioned. Cocaine or crack cocaine was the sole drug mentioned in 36% of cases. An increase in availability of cocaine in the UK has led to a decrease in cocaine prices. This has been associated with higher consumption levels and, in turn, has contributed to an increase in the number of cocaine-related fatalities.⁸

Early childhood trauma appears to be a risk factor in the development of cocaine abuse.⁹

Cocaine users may present in general practice in several ways:

• Psychiatric emergency, patient may present with acute anxiety/paranoia.
• The person discloses abuse and requests help.
• Abuse is not disclosed but the presentation is one of a cocaine-related medical problem such as asthma, chest pains, weight loss (See Drug Abuse and Unusual Presentations).
• A patient on another drug (typically heroin) discloses they are now also using cocaine.
• Unusually a body packer or stuffer requests laxatives.
• Alcohol dependency - one study showed that heavy drinkers who also use cocaine are four times more likely to develop alcohol dependency than those who do not.¹¹
• Cocaine users sometimes present with anti-social behavior disorder.¹²

If patient suffering acute anxiety/paranoia, sit them down and attempt to calm them down. A cocaine 'high' wears off rapidly and the patient should soon become stable enough for further assessment. Benzodiazepines may be required acutely if words and a tranquil environment are not sufficient. If presenting with physical symptoms, perform systematic examination and exclude common acute medical complications - pulmonary oedema, heart failure, myocardial infarction, stroke, hyperthermia.

GPs with special interest should follow local shared-care guidelines. Otherwise, refer to local drug abuse services. All GPs should do a preliminary assessment covering the following:

• History: this should include current drug and alcohol use, previous treatment, current and past medical history, psychological and mental health and forensic history. Why are they consulting you now? Why do they want to stop now?
• The social situation should be assessed during which it should be determined whether anyone else in the household is at immediate risk (e.g. children, vulnerable adults).
• Physical and mental state examination.
• Offer screening for drugs, hepatitis, HIV and sexually transmitted infections (STIs) after appropriate counselling.

(This may need to be adapted to fit local shared-care guidelines)

• Review recent drug and alcohol intake.
• Assess recent risk of blood borne viruses (HIV and hepatitis) and check hepatitis vaccinations are complete.
• Check any change in health, e.g. weight, breathing, palpitations,chest pains.
• Check skin for burns and injecting damage and nose for septum damage.
• Monitor weight, peak flow, pulse rate for arrhythmias and blood pressure (if high may reflect recent use).
• Review sexual health, e.g. contraception, use of condoms, last smear, recent STIs.
• Check whether there have been any recent mental health issues, problems or significant episodes.

The following evidence-based interventions have proved to be helpful:

Psychological intervention by trained therapists

• Cognitive behaviour therapy (CBT) may be helpful.
• Motivational interviewing - this basically involves helping person to think through what changes they need to make in their lives, focussing on the need to stop/limit drug use, reduce harm, prevent relapse.
• Minnesota method - this is available through self-help groups and residential centres. It is not as effective as CBT but useful in some individuals. It is based on the Twelve Step approach used in other forms of addiction such as alcoholism.¹⁶

Prescribed medication (must be used in conjunction with psychological and other therapies)

• Benzodiazepines (e.g. diazepam) - these can help the 'come-down' and treat insomnia. Only use less than 30 mg in these circumstances and for less that 2 weeks.
• Antidepressants - SSRIs are useful only if depression is a feature and other stimulant drug use has stopped. If used with cocaine there is a potential for the rare 'serotonin syndrome' which features autonomic, neuromotor and cognitive-behavioural overstimulation.
• Disulfiram (secondary care only) - there is some evidence that it interferes with the pleasure-inducing ability of cocaine. It is useful especially where there is combined alcohol/cocaine abuse.
• Beta blockers (e.g. propranolol) are useful for anxiety, particularly during withdrawal and to reduce relapse rate but can potentiate cocaine-associated asthma.
• Dexamfetamine (secondary care only) - there is some evidence that it is useful in refractory cases and where there is combined opiate addiction.
• Methadone (secondary care) - there is some evidence of benefit, particularly in mixed cocaine/opiate abuse.
• Sublingual buprenorphine solution (secondary care) - this may be useful, especially in combination with methadone in combined cocaine/opiate abuse.
• Research currently focusses on drugs which affect dopamine metabolism such as methylphenidate and selegiline and a 'cocaine vaccine' which produces antibodies to the drug.

Harm reduction

This is usually part of a shared care protocol and involves discussing the method of cocaine use and how to minimise harm to gums, nose, skin, veins, how to avoid infection, etc.

Residential care

This is useful in some patients. Prior detoxification is not always required.

Aftercare

Continued psychological and social support are required to prevent relapse. Ongoing monitoring by the GP is very helpful, with referral to relapse prevention specialist services as appropriate.