A Textbook of Clinical Pharmacology and Therapeutics

Medical uses of alcohol

Alcoholis used topically as an antiseptic. Systemic alcoholis
used in poisoning by methanol or ethylene glycol, since it
competes with these for oxidation by alcohol dehydrogenase,
slowing the production of toxic metabolites (e.g. formalde-
hyde, oxalic acid).

Management of alcohol withdrawal

A withdrawal syndrome develops when alcoholconsumption
is stopped or severely reduced after prolonged heavy alcohol
intake. Several features of acute withdrawal are due to auto-
nomic overactivity, including hypertension, sweating, tachy-
cardia, tremor, anxiety, agitation, mydriasis, anorexia and
insomnia. These are most severe 12–48 hours after stopping
drinking, and they then subside over one to two weeks. Some
patients have seizures (‘rum fits’ generally 12–48 hours post
abstinence). A third set of symptoms consists of alcohol with-
drawal delirium or ‘delirium tremens’ (acute disorientation,
severe autonomic hyperactivity, and hallucinations – which
are usually visual). Delirium tremens often follows after with-
drawal seizures and is a medical emergency. If untreated,
death may occur as a result of respiratory or cardiovascular
collapse. Management includes thiamine and other vitamin
replacement, and a long-acting oral benzodiazepines (e.g.
chlordiazepoxideordiazepam), given by mouth if possible.
The initial dose requirement is determined empirically and is
followed by a regimen of step-wise dose reduction over the

next two to three days. The patient should be nursed in a quiet

environment with careful attention to fluid and electrolyte

balance. Benzodiazepines (intravenous if necessary, Chapters

18 and 22) are usually effective in terminating prolonged with-

drawal seizures – if they are ineffective the diagnosis should

be reconsidered (e.g. is there evidence of intracranial haemor-

rhage or infection). Psychiatric assessment and social support

are indicated once the withdrawal syndrome has receded.

CENTRALDEPRESSANTS 441

Key points

Acute effects of alcohol

• Central effects include disinhibition, impaired
  judgement, inco-ordination, trauma (falls, road traffic
  accidents), violence and crime.


• Coma and impaired gag reflex; asphyxiation on vomit.


• Convulsions, enhancement of sedative drugs.


• Atrial fibrillation, vasodilation.


• Gastritis, nausea, vomiting, Mallory – Weiss syndrome.


• Hepatitis.


• Hypoglcycaemia, metabolic acidosis, etc.

Key points

Chronic effects of alcohol

• Dependence


• Behavioural changes


• Encephalopathy (sometimes thiamine deficient),
  dementia, convulsions


• Cardiomyopathy


• Gastritis, nausea and vomiting; peptic ulceration


• Pancreatitis


• Cirrhosis


• Myopathy


• Bone marrow suppression


• Gout


• Hypertension


• Fetal alcohol syndrome.

Key points

Delirium tremens

• Mortality is 5–10%.


• There is a state of acute confusion and disorientation
  associated with frightening hallucinations and
  sympathetic overactivity. Delirium tremens occurs in less
  than 10% of alcoholic patients withdrawing from
  alcohol.


• Management includes:
  
  
  • nursing in a quiet, evenly illuminated room;
  
  
  • sedation (either clomethiazole or diazepam);
  
  
  • vitamin replacement with adequate thiamine;
  
  
  • correction of fluid and electrolyte balance;
  
  
  • psychiatric referral.
  
  
  
  

Long-term management of the alcoholic

Psychological and social management: Some form of

psychological and social management is important to help

the patient to remain abstinent. Whatever approach is used,

the focus has to be on abstinence from alcohol. A very small

minority of patients may be able to take up controlled

drinking subsequently, but it is impossible to identify this

group prospectively, and this should not be a goal of

treatment. Voluntary agencies such as Alcoholics

Anonymous are useful resources and patients should be

encouraged to attend them.

Alcohol-sensitizing drugs: These produce an unpleasant

reaction when taken with alcohol. The only drug of this type

used to treat alcoholics is disulfiram, which inhibits aldehyde

dehydrogenase, leading to acetaldehyde accumulation if

alcoholis taken, causing flushing, sweating, nausea,

headache, tachycardia and hypotension. Cardiac dysrhythmias

may occur if large amounts of alcoholare consumed. The

small amounts of alcoholincluded in many medicines may be

sufficient to produce a reaction and it is advisable for the

patient to carry a card warning of the danger of alcohol

administration.Disulfiramalso inhibits phenytoin

metabolism and can lead to phenytoinintoxication.

Unfortunately, there is only weak evidence that disulfiram

has any benefit in the treatment of alcoholism. Its use should

be limited to highly selected individuals in specialist clinics.

Acamprosate: The structure of acamprosateresembles that of

GABA and glutamate. It appears to reduce the effects of

excitatory amino acids and, combined with counselling, it

may help to maintain abstinence after alcoholwithdrawal.