THE ALCOHOLS
Alcohol, primarily in the form of ethyl
alcohol (Ethanol) has occupied an
important place in the history of human
kind for atleast 8,000 yrs.
Alcohol are hydroxy derivaties of alipatic
hydro carbons.Alcohol is manufactured by
fermentation of sugars.
zymase in yeast
C6H12O6 2 CO2 + 2C2 H5 OH
Major source of commercial alcohol is mollases,
byproduct of sugar industries
ALCOHOLIC BEVERAGES :
1. Malted liquors : Beers
2. Wines - Champagne
3. Spirit – Rum, Gin, Whiskey, Brandy
Other forms of Alcohol :
1. Absolute alcohol (Dehydrated alcohol) – 99%
Ethyl Alcohol
2. Rectified spirit – 90% Ethyl Alcohol
3. Proof spirit – 100% Ethyl Alcohol
Pharmacological actions :
Central Nervous system : The central
nervous system is markedly affected by
acute alcohol consumption. Alcohol
causes sedation & relief of anxiety and at
higher concentration slurred speech,
ataxia, impaired judgement and
disinhibited behaviour a condition usually
called intoxication or drunkenness
Like other sedative hypnotic drugs
alcohol is a CNS depressant.
3. At high blood concentration, it induces coma,
respiratory depression and death
BAC(mg/dL)1 Clinical Effect
50-100 Sedation subjective “high,” increased
. reaction times
100-200 Impaired motor function, slurred
speech, ataxia.
Emesis, stupor
200-300
Coma
300-400
>500 Respiratory depression, death
Mechanism of Alcohol : It enhances the action of
GABA at GABAA receptors & inhibits the ability of
glutamate to open the cation channel associated
with the NMDA receptors
Heart : significant depression of myocardial
contractility has been observed in individuals
who consume moderate amounts of alcohol.
Myocardial Biopsies in humans before and after
infusion of small amounts of alcohol show ultra
structural changes that may be associated with
impaired myocardial function. Acetaldehyde is
implicated as a cause of heart abnormalities by
altering myocardial stores of catecholamines.
Smooth muscle : Ethanol is a vasodilator probably
due to the depression of vasomotor center. In
overdose cause hypothermia marked in cold
environment. It also relaxes uterus – was used
intravenously for the suppression of premature
labour.
Liver : liver disease is most common medical
complication of alcohol abuse. It is estimated
that about 15 – 30% of chronic heavy drinkers
eventually develop severe liver disease. Alcoholic
fatty liver, a reversible condition may progress to
alcoholic hepatitis and finally to cirrhosis & liver
failure.
GIT : Ingestion of alcohol increases gastric
and pancreatic secretions & alter the
mucosal barriers & cause gastritis and
pancreatitis.
Alcohol reversibly injures the small intestine
and cause diarrhea, weight loss and
multiple Vitamin deficiencies.
Nervous system : Chronic use of alcohol cause
tolerance and physical dependence.
Chronic alcohol drinkers when forced to reduce or
discontinue alcohol experience a withdrawal
syndrome. Alcohol withdrawal symptoms
experience hyperexcitability in mild cases and
convulsions, toxic psychosis and delirium
tremens in severe ones.
It also cause peripheral neuropathy (distal
paresthesia of hands and feet), gait disturbances
& Wernicke-Korsakoff syndrome
Wernicke-Korsakoff syndrome :
It include paralysis of external eye
muscles, ataxia and confused state
progress to coma and death. It is
apparently associated with thiamine
deficiency but is rarely seen in the
absence of alcoholism.
Blood :
It cause anemia, folic acid deficiency and
hyperlipidemia. Iron deficiency anemia
result from GI bleeding.
Endocrine system & Electrolyte balance :
Cause gynecomastia and testicular
atrophy in endocrine system.
Chronic alcoholism produce ascities edema
& effusions. These factors may be related
to decreased protein synthesis and portal
hypertension. Some develop hypoglycemia
and ketosis.
Immune system : Alcoholic are prone to
develop respiratory infections such as
pneumonia and tuberculosis
Cancer : Chronic alcohol use increase the
risk of cancer mouth, pharynx, larynx,
esophagus and liver.
Skeletal muscle : chronic alcohol use cause
weakness and myopathy
Kidney : Diuresis is often noticed after
alcohol in take. This is due to water
ingested with drinks and alcohol induced
inhibition of ADH secretions.
Sex : Chronic alcoholism can produce
impotence, testicular, atrophy,
gynaecomastia and infertility.
Pharmocokinetics :
Ethyl alcohol converted into acetaldehyde
&acetate by alcohol & aldehyde dehydrogenase
respectively.
Ethyl Alcohol is excreted through
kidney and lungs. Concentration in exhaled air
is about 0.05% of blood concenteration this is
utilized for medicolegal determination of
drunken state.
Metabolism of alcohol follow zero order kinetics that is
constant amount of alcohol is degraded in unit time
irrespective of blood concentration.
Interactions :
1. Alcohol synergises with tranqulizers anti depressants,
antihistamanics hypnotics, opioids – marked CNS
depression.
2. Sulfonyurea (Chlorpropamide), cephalosporins
(cefoperozone, moxalactam, cefamandole) and
metronidazole produce – disulfiram like reaction when
they consume alcohol.
3. Acute alcohol in take inhibit microsomal enzyme system.
Chronic use induce microsomal enzyme system.
4. Insulin and sulfonylurea enhances hypoglycemia
with alcohol
5. Aspirin cause more GI bleeding when taken with
alcohol
6. Alcoholics prone to develop paracetamol toxicity
due to toxic metabolite
Food value : It produce 7 cal/gm it does not
supply essential nutrients it is an imperfect and
expensive food.
Contraincations : Peptic ulcer, epilepsy, severe
liver disease, unstable personalities and
pregnant women.
Side effects : Nausea, vomiting, flushing,
hangover, traffic accidents. They should
not drive car or operate machinery.
Toxicity : Even moderate drinking during
pregnancy produce foetal alcohol syndrome
resulting in intra uterine and postnatal growth
retardation, low IQ, facial and other
abnormalities and immunological impairment –
increased susceptibility to infections. Heavy
drinking by pregnant mother in addition cause
miscarriage, stillbirth and low birth weight
babies.
Acute alcohol and toxicitation : Hypotension,
gastritis, hypoglycaemia, collapse, repiratory
depression, coma and death.
Treatment : symptomatic and supportive line of
treatment. For hypoglycaemia, glucose infusion
is given.
Chronic Alcoholism Treatment : Psychological and
medical supportive measures are made during
withdrawal. To suppress withdrawal syndrome
benzodiazepines are used. Clonidine – alpha2 agonist
and propranolol are also used
Naltrexone is used to prevent relapse of alcoholism. It
reduces alcohol craving.
Other drugs used are acamprostate (NMDA Antagonist)
and ondansetron.
Disulfiram (aldehyde dehydrogenase inhibitor) : It
inhibits the enzyme aldehyde dehydrogenase when
alcohol is ingested after taking Disulfiram the
concentration of aldehyde in tissues and blood rises
and cause flushing, burning sensation, throbbing head
ache, perspiration, uneasiness tightness in chest,
dizziness, vomiting , visual disturbances, mental
confusion, fainting and collapse (aldehyde syndrome)
Disulfiram has been used as aversion technique in
chronic alcoholics who are motivated and sincere
desire to leave the habit.
1st day – 1 gm
2nd day – 0.75 gm
3rd day – 0.5 gm and
Subsequently 0.25gm for 1 – 2 weeks
Side effects : Rashes, metallic taste, nervousness,
abdominal upset. It inhibits number of enzymes
(alcohol dehydrogenase, dopamine beta
hydroxylase and several cytochrome P450
Isoenzymes. Thus it prolongs plasma half life of
many drugs.
Therapeutic uses : Antiseptic, counter
irritant, to prevent bed sores, to reduce
body temperature in fever, intractable
neuralgias (trigeminal and others), severe
cancer pain, to ward off cold, appetite
stimulant, one drop in nose is used in
fainting/hysteria, methanol poisoning
Methyl alcohol:
Methanol
15 ml – blindness
30 ml – death
Fatal dose – 75 – 100 ml
Pharmacokinetics:
Zero order kinetics
Formaldehyde & formic acid
Blindness (retinal damage)
Treatment
Dark room
I.V sodium bicarbonate
gastric lavage
Hypokalemia – pot. Chloride
Ethanol administered orally by nasogastric
tube
Fomepizole
Folate therapy-calcium leucovorin
Haemodialysis
