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 most commonly 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.

Effects of cocaine³

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 intravenously (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 'Epidemiology', below).

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

Epidemiology

In 2005 it was estimated that around 13% of people in the UK aged 16 to 29 years (who often visit pubs or wine bars) used cocaine in the previous 12 months. The percentage among less frequent visitors to pubs and wine bars was 3.7%.⁵

The Home Office survey of declared drug use for 2008-9 found 36.8% had used illicit drugs, 10.1% had used drugs in the previous year and 5.9% had done so in the previous month.¹ Levels of Class A drug use were lower than overall drug use, with 15.6% having used a Class A drug at least once in their lifetime, 3.7% having done so in the previous year and 1.8% in the previous month. Cannabis is the type of drug most likely to be used.

One review of information from official UK sources found that 1,022 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.⁶

Early childhood trauma appears to be a risk factor in the development of cocaine abuse.⁷

Presentation⁸

Cocaine users may present in general practice in several ways:

• Psychiatric emergency patient, who 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 separate article Drug Abuse - 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.⁹
• Cocaine users sometimes present with antisocial behaviour disorder.¹⁰

Managing a psychiatric and/or medical crisis^8,11

If the patient is suffering from 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 the patient presents with physical symptoms, perform a systematic examination and exclude common acute medical complications - pulmonary oedema, heart failure, myocardial infarction, stroke, hyperthermia.

Managing an initial request for help

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:^3,12

• 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.

Ongoing care

(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 that hepatitis vaccinations are complete.
• Check any change in health, e.g. weight, breathing, palpitations, chest pains.
• Check the patient's skin for burns and injecting damage and their nose for septum damage.
• Monitor weight, peak flow, pulse rate for arrhythmias and blood pressure (if high, this may reflect recent use).
• Review sexual health, e.g. contraception, use of condoms, last smear test, recent STIs.
• Check whether there have been any recent mental health issues, problems or significant episodes.

Evidence-based interventions^8,13,14

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

Psychological interventions

• Contingency management - incentives (such as shopping vouchers) are given for drug-free periods of time (confirmed by blood testing).¹⁵
• Cognitive behavioural therapy (CBT) may be helpful.
• Motivational interviewing - this basically involves helping the person to think through what changes they need to make in their lives, focusing 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 than two weeks.
• Antidepressants - selective serotonin reuptake inhibitors (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.¹⁷
• Sublingual buprenorphine solution (secondary care) - this may be useful, especially in combination with methadone, in combined cocaine/opiate abuse.
• Research currently focuses on drugs which affect dopamine metabolism, such as methylphenidate and selegiline and a 'cocaine vaccine' which produces antibodies to the drug.

The National Institute for Health and Clinical Excellence (NICE) suggests methadone or buprenorphine be used as first-line in opioid detoxification.¹²

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 and 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.

Document references

1. Drug Misuse Declared: Findings from the 2008/09 British Crime Survey, England and Wales, Home Office, July 2009
2. Cocaine and Crack, DrugScope
3. Guidance for Working with Cocaine and Crack Users in Primary Care, Royal College of General Practitioners (2004)
4. Hser YI, Huang D, Brecht ML, et al; Contrasting trajectories of heroin, cocaine, and methamphetamine use. J Addict Dis. 2008;27(3):13-21. [abstract]
5. Watson R; Cocaine use rises in Europe while overall drug use levels out. BMJ. 2007 Dec 1;335(7630):1117.
6. Schifano F, Corkery J; Cocaine/crack cocaine consumption, treatment demand, seizures, related offences, prices, average purity levels and deaths in the UK (1990 - 2004). J Psychopharmacol. 2008 Jan;22(1):71-9. [abstract]
7. Back SE, Brady KT, Waldrop AE, et al; Early life trauma and sensitivity to current life stressors in individuals with and without cocaine dependence. Am J Drug Alcohol Abuse. 2008;34(4):389-96. [abstract]
8. Watson R; Cocaine use rises markedly among 16-29 year olds. BMJ. 2002 Oct 12;325(7368):794.
9. Rubio G, Manzanares J, Jimenez M, et al; Use of cocaine by heavy drinkers increases vulnerability to developing alcohol dependence: a 4-year follow-up study. J Clin Psychiatry. 2008 Apr;69(4):563-70. [abstract]
10. Mariani JJ, Horey J, Bisaga A, et al; Antisocial behavioral syndromes in cocaine and cannabis dependence. Am J Drug Alcohol Abuse. 2008;34(4):405-14. [abstract]
11. Aslibekyan S, Levitan EB, Mittleman MA; Prevalent cocaine use and myocardial infarction. Am J Cardiol. 2008 Oct 15;102(8):966-9. Epub 2008 Aug 5. [abstract]
12. Drug misuse: opioid detoxification, NICE Clinical Guideline (2007)
13. Drug Misuse and Dependence - UK Guidelines on Clinical Management, NHS National Treatment Agency, September 2007
14. Gossop M, Trakada K, Stewart D, et al; Reductions in criminal convictions after addiction treatment: 5-year follow-up. Drug Alcohol Depend. 2005 Sep 1;79(3):295-302. Epub 2005 Mar 26. [abstract]
15. Psychosocial interventions for drug misuse; NICE Guidance CG51 2007
16. Approaches to Drug Abuse Counseling, National Institute on Drug Abuse, 2003
17. Drug misuse - methadone and buprenorphine, NICE Technology Appraisal Guidance (2007)

Internet and further reading

• National Treatment Agency for Substance Misuse (NTA)
• National Drugs Helpline
• HIT - Health Information with leaflets for patients and families.
• Release; An organisation which provides advice to drug users, families, NHS and voluntary organisations