alcohol mbbs 2014

8/12/2019 Alcohol MBBS 2014

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Ethyl alcohol

Alcohol is important in medicine -

misuse/abuse

Present in beverages/used as drug

Alcoholism is a complex disorder with a

genetic and environmental component

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Pharmacological actions -

Local

Mild rubefacient - Cutaneous vasodilation

Promotes heat loss

Astringent; antiseptic (20-70%=90%)

Injected to nervepermanent damage

(sclerosant)

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William Shakespeare (15641616). The Tragedy of

Macbeth.

Lechery, sir, it provokes, and unprovokes;

It provokes the desire, but it takes away

the performance;

It makes him, and it mars him;

It sets him on, and it takes him off;

It persuades him, and disheartens him; Giveth redness of nose, sleep and urine

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CNS effects

CNS depressant

Inhibition is lost

At higher concentrations - slurred speech, ataxia, impaired judgment, motor

incoordination, increased self-confidence & disinhibited behavior

Induces sleep-not dependable

Chronic: dementia, wernicks, cognition disorders

Mechanism of CNS action involves:

potentiation of GABA receptor

inhibition of Glutamate receptor neurotransmission

Enhances action at other ligand-gated ion channels like 5HT3, NN, glycine receptors

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CVS

Small dosescutaneous vasodilatation

Moderate dose - BP central sympathetic stimulation

High dose - BP Myocardial + vasomotor center depression

Chronic alcoholismcardiomyopathy,

conduction defect, ventricular hypertrophy,

atrial & ventricular arrhythmias

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Blood

Low doses- HDL & CHD risk

Do not advice non drinkers to drink

Body temperature

Combats cold??feeling of warmth

Heat loss is increased-vasodilation

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Gastric mucosa

disrupt the gastric mucosal barrier and cause acute and

chronic gastritis

Promotes the release of gastrin and histamine

gastric acid secretion

act synergistically with H. pylorito delay healing

Inflammation and bleeding by ulceration of the stomach

lining

Acute pancreatitis19


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Kidney

Diuresis - Antidiuretic hormone

Uterus Relaxant

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Pharmacokinetics

Orally - rapidly absorbed from stomach and small intestine

Depends on the presence of food

Vol.of distribution wide

Metabolism-zero order [12ml/hr]

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Ethanol-metabolism

Genetic factors

In 50% of Asian people, an inactive genetic

variant of one of the aldehyde

dehydrogenase isoforms (ALDH-2) is

expressed;

These individuals experience a disulfiram-

like reaction after alcohol, and the incidence

of alcoholism in this group is extremely low

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Adverse health effects

>3 drinks/day is associated with adverse health effects

1 drink =18 ml of alcohol

350ml of beer or 150 ml of wine or 45 ml of spirit

1. GITpeptic ulcer, hyperacidity, nutritional deficiency,

pancreatitis

2. Lowers seizure threshold

3. Liver disease

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Adverse health effects

Abuse

Fetal alcohol syndrome

HTN, cardiomyopathy

CNSimpaired mental and physicalperformance

Wernickes encephalopathy, Korsakoffspsychosis

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Teratogenic effects

Fetal alcohol syndromeCharacteristics of fetal alcohol syndrome include:

(1) intrauterine growth retardation,

(2) microcephaly,

(3) poor coordination,

(4) underdevelopment of mid-facial region

(appearing as a flattened face),

(5) minor joint anomalies

Severe cases - congenital heart defects and mental retardation

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Therapeutic UsesTOPICAL

Antiseptic Counterirritant Prevent bedsores To reduce body temp???

SYSTEMIC

Trigeminal neuralgia (to destroy painful nerves)

Carminative and appetizer

Treat Methanol poisoning

Fainting hysteria 10


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Contraindication

Peptic ulcer Epileptics

Liver disease

Pregnancy-a. Moderate drinking-fetal syndromes

b. Heavy-miscarriage, stillbirths

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Acute Ethanol Intoxication..

Acute Effects: Vasodilation, Tachycardia

G.I. Irritation, respiratory depression

Management: Prevention of respiratory depression;

aspiration of vomitus

Treatment of: Hypoglycemia & ketosis with glucose

Treatment of dehydration with electrolytes

Thiamine - to protect against Wernicke-Korsakoff

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Alcoholism & Treatment

Chronic alcohol use (alcoholism) results in CNS adaptations called

Tolerance and Physical dependence

Withdrawal symptoms during abstinence from alcohol include

delirium tremens, convulsion, seizure, tremors and nausea

TREATMENT / DETOXIFICATION

Substitution of a long acting sedative/hypnotic drug for ethanol, i.e.

Benzodiazepine or Oxazepam

I.V. infusion of Phenytoin to stop Seizures

Disulfiram (250 mg daily)

Supplementary dietary thiamine to replace body vitamin loss 6


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Treatment of alcoholism1.

Motivated alcoholic and complete abstinence

2. Disulfiramused as a aversion technique in chronic

alcoholics

3. Naltrexonelong acting opioid antagonist - craving for

alcohol and prevent relapse

4.Acamprosate; Complex receptor action[GABA & NMDA]

decreases drinking frequency and reduces relapse in abstinent

alcoholics

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Disulfiram

Inhibits ALDH activity - blood acetaldehyde concentration rise to 5

to 10 times

Ingestion of alcohol by individuals pretreated with disulfiram - rise

to marked signs and symptoms of acetaldehyde poisoning. Face feels hot , flushing

Throbbing ache in the head and neck, Respiratory difficulties,

nausea, copious vomiting, sweating, thirst, chest pain,

hypotension, marked uneasiness, weakness, vertigo, blurred

vision, and confusion

A/EPsychosis, hepatitis, rashes, metallic taste

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Methyl alcohol

(Methanol/Wood alcohol)

Metabolized to formaldehyde and formic acid

CNS depressant

Formic acid is responsible for toxic effect

Manifestationvomiting, headache,

epigastric pain, dyspnoea, hypotension,

acidosis, retinal damage, death

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Leucovorin


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Summary

Actions-CNS,CVS,LOCAL,

KIDNEY,STOMACH

PK-Zero order and metabolism

ADEs-peptic ulcer,

cirrhosis,CNS,cardiomyopathy, psychosis

DIs---Disulfiram like reactions

Uses

Methyl alcohol poisoning

last

alcohol mbbs 2014

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