Cocaine abuse and dependence
Cocaine abuse is defined as the continued use of cocaine/crack despite it causing significant problems, which may be social, neuropsychiatric or physical.
Cocaine hydrochloride (HCl) is made from the leaves of the coca shrub. It is normally bought as a white powder, which is usually snorted or smoked. Freebasing is where cocaine HCl (the salt) is dissolved in water and heated with baking soda, ether or ammonia to free the cocaine alkaloid base. This combusts more readily making the cocaine more potent. Crack is a form of freebase cocaine made by using baking soda, which looks like little lumps (‘rocks’) and makes a crackling sound when burnt.
Street names for cocaine include ‘C, charlie, coke, dust and white’, and for crack include ‘base, freebase and rock’. The street term ‘freebasing’ means smoking cocaine, either as the salt or base. Cocaine and crack can also be injected, although this is far less common.
7% of 20–24 year olds have tried cocaine, mainly snorting. About 10–15% of those who try snorting cocaine become abusers. Crack is less commonly used, but addiction occurs faster. Crack is linked with areas of social deprivation, whereas cocaine HCl tends to be associated with an expensive lifestyle. Cocaine HCl and crack abuse is rising.
Cocaine HCl and crack are strong, short-acting stimulant drugs. They are not physically addictive in the same way as opiates, but cocaine addicts will compulsively take doses in a ‘binge’ in order to keep experiencing the highs and to avoid the depression and fatigue that occur when the drug wears off. Tolerance does seem to occur to some extent. Snorting cocaine HCl leads to effects within minutes, which last about half an hour. Base forms of cocaine, including crack, have a more rapid onset but a much shorter duration of action. When cocaine is taken with alcohol, its effects are increased by an active metabolite, which only forms in the presence of alcohol.
After taking cocaine, the user feels intense euphoria. Physical side effects include dilated pupils, dry mouth, sweating, tachycardia and loss of appetite. Within half an hour of the last dose of a binge, there is a ‘crash’ when the user feels intense cravings, depression and anxiety. After a further 1–4 hours, they usually sleep for hours to days, intermittently waking up with hunger (‘the munchies’). After a few days, the user becomes low in mood, with lack of motivation, impairment of memory and inter-mittent anxiety, even suicidal ideation. Long-term users may become persistently restless, with anorexia, weight loss and insomnia.
A history should be taken of recent and previous cocaine use, including methods of administration, use of other drugs, alcohol intake, previous rehabilitation and any problems associated with drug use. A close social history should be taken, as well as a medical history and examination.
Physical: Snorting cocaine repeatedly causes damage to the nasal mucous membranes with septal perforation, cribiform plate damage and CSF rhinitis. Smoking can cause granulomas and pulmonary oedema. Injecting carries risks of abscesses, infective endocarditis, HIV and hepatitis infection. Other medical complications include hypertension, myocardial infarction (MI) due to coronary artery spasm, arrhythmias, seizures, stroke and cardiorespiratory arrest.
Neuropsychiatric: Anxiety, paranoia, depression and hallucinations.
Social: The most common reason for a cocaine addict to present for treatment of dependency is running out of money, as a cocaine or crack binge can cost hundreds to thousands of pounds. Other problems include loss of job and criminal activities such as stealing, prostitution and drug dealing.
These depend on the presentation of the individual. Cocaine use can be tested for using a urine screen. Investigations may be needed for possible complications such as MI, arrhythmias, stroke and infections.
Cocaine intoxication: Initial management includes ensuring a clear airway and ventilation if needed.
1. Seizures are treated with diazepam or lorazepam. Phenytoin may be needed.
2. Agitation and hypertension often respond to diazepam. Haloperidol and phenothiazines should be avoided, as they increase the risk of seizures.
3. Persisting hypertension should be treated with intravenous glyceryl trinitrate (GTN), with calcium antagonists as second line therapy. β -blockers should be avoided (may cause paradoxical hypertension and coronary vasoconstriction due to unopposed alpha effects).
4. Aspirin, sublingual GTN and diazepam should be given to all patients who have chest pain. If pain con-tinues, intravenous GTN should be commenced and if despite this, the ECG shows an acute MI, throm-bolytic therapy as for a conventional MI should be given, unless there are any contraindications.
5. Cardiac arrhythmias require specialist advice, for example from the National Poisons Information Service (NPIS).
6. Cocaine abusers should be referred to a drug rehabilitation counsellor or centre. There are no serious physical effects from withdrawal so sedatives or a replacement drug are not needed. Propanolol may help anxiety (but may exacerbate cocaineinduced hyper-tension or myocardial ischaemia) and antidepressants may be indicated.