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. Cocaine is the most commonly used class A drug, overtaking the use of heroin.¹

• 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.

Voir aussi les articles sur Drug Misuse and Dependence et Assessment of Drug Dependence.

Effects of cocaine

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.

• Chronic cocaine use is also associated with cardiovascular adverse effects, and functional brain impairments potentially mediated by vascular pathology.²

Powder cocaine is the most commonly used stimulant in the UK and the second most prevalent drug overall. In the most recent surveys available (2019), use in the previous year was reported at 2.9% in England and Wales, the highest figure since 2008 to 2009 (3.0%), and 1.8% in Northern Ireland. Use of cocaine (including crack) in Scotland had dropped from 3.7% in 2008 to 2009 to 2.3%. Powder cocaine was the third most commonly used drug among people aged 16 to 24 in England and Wales (6.2%), after cannabis (17.3%) and nitrous oxide (8.7%).

Although the crack cocaine epidemic has declined since 2012-14, the UK has the highest levels of crack cocaine problems in Europe. Crack is associated with chaotic lifestyles and crime, particularly among people also using opioids and is mainly seen in England. Household surveys are likely to under report this group, so prevalence of crack use is estimated as part of the indirect prevalence estimates for high risk drug use. The prevalence of crack users within the population aged 15 to 64 in England was estimated to be 5.1 users per 1,000 in 2016 to 2017.

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 and weight loss (see the separate Drug Abuse - Unusual Presentations article).

• A patient on another drug (typically heroin) discloses they are now also using cocaine.

• Unusually, a body packer or stuffer requests laxatives.

• Exacerbation of mental health problems, eg depression, anxiety or insomnia may be caused by comorbid substance use, including cocaine.

• 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.⁴

• Cocaine users sometimes present with antisocial personality disorder.⁵

If the patient has 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.

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: ⁸

• History: this should include current drug and alcohol use, previous treatment, current and past medical history, psychological and mental health and forensic history. Establish why they are consulting you now and why 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 (eg, 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 but the general principles are as follows:

• 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 - eg, 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 - eg, contraception, use of condoms, last smear test, 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 interventions¹¹

• Because no medications have been approved for the treatment, psychosocial treatment is currently the standard treatment.

• Contingency management - incentives (such as shopping vouchers) are given for drug-free periods of time (confirmed by blood testing).¹²

• Thérapie cognitivo-comportementale (TCC) 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 and 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.¹⁰

Prescribed medication (must be used in conjunction with psychological and other therapies)¹³

• Benzodiazepines (eg, 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 (eg, propranolol) are useful for anxiety, particularly during withdrawal and to reduce relapse rate but can potentiate cocaine-associated asthma.

• Dexamphetamine (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 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 Care Excellence (NICE) suggests methadone or buprenorphine be used as first-line in opioid detoxification.⁸

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 and 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.