Download Alcohol (ethanol): Pharmacological effects

Alcohol (ethanol):
Pharmacological effects
Chih-Chia Lai
Department of Pharmacology
Tzu Chi University
2011-3-28
Drugs of Abuse(濫用藥物)
– 類鴉片藥物:
• Heroine, Morphine
– 中樞神經興奮劑:
• Amphetamine, Methamphetamine, MDMA, Cocaine
– 中樞神經抑制劑：
• FM2
– 中樞神經幻覺劑：
• Ketamine, LSD, Marijuana, Phencyclidine (angel dust)
– 酒精(alcohol)和尼古丁(nicotine)
Lifetime Prevalence, mental
health and addictive disorders
•
•
•
•
•
•
•
•
•
Alcoholism (dependency & abuse)
Phobias (恐懼症)
Drug Abuse/Dependence
Major Depression (憂鬱症)
Antisocial Personality
Obsessive Compulsive Disorder
Panic Disorder
Schizophrenia
Mania
- 13.7%
- 12.6%
- 6.1%
- 5.1%
- 2.5%
- 2.5%
- 1.5%
- 1.0%
- 0.4%
Alcohol as a drug
 Drug
 a substance, other than food, used in the prevention, diagnosis,
alleviation, treatment, or cure of disease
 A substance other than food intended to affect the structure or
function of the body
 Alcohol is a psychoactive drug that is a CNS (central
nervous system) depressant
 Alcohol is the second most widely used and abused of all
psychoactive drugs
 Alcohol is an addictive drug
 Alcohol is considered as a social lubricant
Why people view alcohol as a non-drug
Alcohol is legal
Advertising and media promote drinking as
normal
Large distribution and sales of alcohol
Long history of alcohol use
Negative Impact of Alcohol
 Excessive alcohol (alcohol abuse) use can result in
serious physical and mental problems.
 Chronic excessive use that involves a compulsion to
drink, increased tolerance, and withdrawal
symptoms is called alcohol dependence or,
alternatively, alcoholism.
 Tolerance: the capacity of the body to endure or become less
responsive to a substance (as a drug) or a physiological insult with
repeated use or exposure
 Withdrawal syndrome: the development of a substance-specific
syndrome that follows the cessation of, or reduction in, intake of a
psychoactive substance that the person previously used regularly
Ethanol Tolerance
 Chronic tolerance: produced by repeated
administration of ethanol over a period of
days or weeks.
 Acute tolerance (tachyphylaxis): that
appears within minutes after a single dose.
 Cross-tolerance: the resistance to one or
several effects of a compound as a result of
tolerance developed to a pharmacologically
similar compound. It is common practice to
take alcohol concurrently with other
drugs
Ethanol dependence
 Physical dependence manifested by withdrawal
reactions: hyperexcitability in mild cases,
convulsion, toxic psychosis, and delirium tremens
(酒狂) in severe ones. The severity of withdrawal
reactions depends on dose and frequency of use,
and may be life threatening.
 Psychological dependence is characterized by a
compulsive desire (or craving) to experience the
rewarding effects of alcohol or to avoid the
negative consequences of withdrawal.
Positive Impact of Alcohol
Moderate consumption of alcohol may prolong life span
•
In recent years dozens of cohort studies from
all over the world have associated moderate
alcohol consumption with reduced risk for
cardiovascular disease, decreased overall
mortality rates and other potentially
improved health conditions.
自由電子報，2011/3/23
• 每天一杯酒精飲料有助預防心臟疾病，根據一份針對過去30
年的研究所做的評估指出。此一刊登於《英國醫學期刊》的
研究顯示，適量飲酒者比從未喝酒的人，心臟疾病降低14％
到25％。
• 另一份由同一個加拿大研究團隊撰寫的文章顯示，酒精增加
「好」膽固醇值，但專家說，這不是開始飲酒的理由。
• 卡加立大學科學家評估1980到2009年間的84份研究，評估顯
示，喝少量酒精（2.5公克到14.9公克）的人，整體而言死亡
風險比不喝酒的人低。研究人員也說，規律適量的飲酒，各
類型心血管疾病罹患率最高可降低25％。
• 少量喝酒雖然對降低中風與中風死亡數有好處，但較重度的
喝酒顯著增加風險。卡加立大學人口與公共衛生研究院的蓋
里教授告訴英國廣播公司：「我們的廣泛研究顯示，喝一杯
，或一到兩杯酒會有益處。」
喝酒盛行率
 根據統計台灣地區十五歲以上人口之喝酒盛行率為
18.83% (男：29.18%、女：7.80%)。
 而在國中生的盛行率：男生為21.8%、女生為10.5%；
在高中生的盛行率：男生佔百分之二十七‧ 九、女生
佔百分之十七‧一，顯示青少年飲酒問題也趨於嚴重。
 而台灣原住民，嚴重的嗜酒問題，一直是影響健康狀
況的主要因素之 一。台灣原住民酒精濫用和酒精依賴
終身盛行率高達百分之二十以上，造成嚴重的健康與
社會問題。
Blood Alcohol Concentration (BAC)
 The effects of alcohol on the human body depend on the
amount of alcohol in the blood (blood alcohol concentration)
 BAC produced depends on




Presence of food in the stomach
Rate of alcohol consumption
Concentration of alcohol
Drinker’s body composition
 Almost 95% of consumed alcohol is inactivated by liver
metabolism.
 The liver metabolizes alcohol at a slow and constant rate and is
unaffected by the amount ingested.
 Thus, if one can of beer is consumed each hour, the BAC will
remain constant.
酒精之排泄(drug excretion)
大部分濫用藥物
酒精
Blood alcohol concentration (BAC) and clinical effects
in non-tolerant individuals
50-100 mg/dl (0.05-0.10%)
Sedation, increased reaction time, subjective “high”
100-200 mg/dl (0.1-0.2%)
impaired motor function, slurred speech , ataxia
200-300 mg/dl (0.2-0.3%)
Emesis, stupor
300-400 mg/dl (0.3-0.4%)
Coma
≥400 mg/dl (0.4%)
Respiratory depression, death
 CNS stimulation (disinhibition) → CNS depression
 Sudden death from either respiratory depression or
arrhythmias may occur when large quantities are drunk
rapidly.
Drug A : ethanol
Drug B : benzodiazepines
酒精濃度檢測
• 駕駛人飲酒後其吐氣所含酒精濃度超過每公
升○‧二五毫克或血液中酒精濃度超過百分
之○‧○五以上，不得駕車。 (道路交通安全
規則第114條)
• 血液酒精濃度：吐氣每公升酒精含量0.25mg
（毫克）＝血液中酒精濃度0.05％
(50mg/100ml)
Alcohol & Calories
 Alcoholic beverages have no vitamins,
minerals, protein, or fat – just a large amount
of carbohydrates and usually calories
 Alcohol provides more calories per gram
than does carbohydrate or protein and
only slightly less than does pure fat.
Because it can provide many calories, the
drinker’s appetite may be satisfied; as a
result, he or she may not eat properly,
casuing alnutrition.
The Hangover
 The symptoms: fatigue combined with
nausea, upset stomach, headache, sensitivity
to sound, and ill temper
 These symptoms are usually most severe
many hours after drinking, when little or
no alcohol remains in the body.
 No simple explanation exists for what
causes the hangover.
Effects of Alcohol on Organ
Systems and Bodily Functions
•
•
•
•
•
•
•
•
Brain and nervous system
Liver
Digestive system
Blood
Cardiovascular system
Sexual organs
Endocrine system
Kidneys
The effects of Alcohol on Liver
• Alcohol causes a spectrum of liver injury that can
progress from fatty liver to alcoholic hepatitis
(often considered an intermediate stage) to
cirrhosis.
• As little as 20 g of alcohol in women or 60 g in
men can cause serious liver damage when
consumed daily for several years. Consuming
more than 60 g/day for 2 to 4 wk produces fatty
liver even in otherwise healthy men; 80 g/day may
lead to alcoholic hepatitis; and 160 g/day over a
decade can lead to cirrhosis.
The cardiovascular effects of Alcohol: the Good
 The National Institute on Alcohol Abuse and Alcoholism
defines moderate alcohol consumption as “no more than two
standard drinks per day for most men and no more than one
standard drink per day for most women.” A standard drink
contains 12 g of alcohol.
 It have suggested that one to two standard drinks per day is
associated with reduced risk of coronary artery disease.
 24 g alcohol per day (two drinks) reduced the risk of
ischemic stroke and total stroke.
 American Heart Association/American College of Cardiology
science advisories conclude that in the absence of proof of
causality, the use of alcohol as a cardioprotective strategy is
not recommended.
The cardiovascular effects of Alcohol: the Bad
 The adverse effects of immoderate alcohol consumption on
the cardiovascular system include cardiomyopathy,
hypertension, cardiac arrhythmias, and stroke.
 Alcoholic cardiomyopathy generally occurs after long-term,
heavy drinking (more than six standard drinks per day for
longer than five years).
 Studies show an association between long-term alcohol
consumption of 30 to 60 g (three to five drinks) or more per
day and higher systolic and diastolic blood pressures
 60 g or more alcohol per day per day increased the risk of
ischemic stroke and total stroke.
 Heavy, long-term drinking and binge drinking also are
associated with atrial and ventricular arrhythmias, some
nonspecific electrocardiographic changes, and sudden
cardiac death
Effects of Alcohol on Sexual Organs
The following dialogues from Shakespeare describe
some of the effects of alcohol.
Macbeth (Act 2, scene 3):
Macduff: What three things does drink provoke?
Porter: Marry, sir, nose-painting, sleep, and urine.
Leachery, sir, it provokes, and unprovokes;
It provokes the desire, but it takes away the
performance.
Alcohol and Pregnancy
 Moderate to excessive drinking during pregnancy
can result in
– Spontaneous abortion
– Damage to fetus (fetal alcohol syndrome, FAS)
• Damage dose-related
• A safe lower level of alcohol consumption has
not been established for pregnant women
 Fetal alcohol syndrome (FAS)
 Facial abnormalities, where there is
an increased distance between the
inner corners of the eyes, and a
thin upper lip.
 Mild to severe mental retardation
resulting in learning difficulties.
 Low birth weight and height that
persists through early childhood.
 Abnormalities of the heart and
other organs.
濫用藥物之毒性作用
藥物類別
濫用藥物
濫用潛力
中樞神經幻
覺劑
LSD
+
Ethanol
Distortion of
perception,mood,
and thought
戒斷徵候
不良後果
-
+++
Neurotoxicity,
Flashbacks,
Toxic psychosis,
PCP can be
lethal
Severe CNS
depression
PCP
酒精
急性作用
++
Stimulant at low
doses including
euphoria and
increased
talkativeness
Depressant
at high doses
producing
ataxia, slurred
speech,
decreased
motor
Skills
+++
+++
Tremor
Nausea
Sweating
Hypertension
Seizure
Delirium
Liver disease,
Fetal alcohol
syndrome,
Life-expectancy
decreased
by 10 yrs,
Lifethreatening
Contributes to
highway
Fatalities