ANTH106 Lecture Notes - Lecture 5: Hydromorphone, Hyoscyamus Niger, Fentanyl
2 Jun 2018
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Department
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Professor
Pharmacology and Psychology of Drug Use:
What is pharmacology?
• The science and study of drugs and their actions
o Phamakon (Greek) for Drug
o Logos (Greek) for Reasoned Discourse (i.e. science)
• Considers
o Chemical and physical properties of drugs
o Biochemical, physiological and psychological
(psychopharmacology) effects of drugs
o Mechanism of action
o Uses and adverse effects
• Knowledge of drugs and their uses in disease goes back further than
Hippocrates and this formed the basis for modern pharmacology –
‘Father’ of modern pharmacology = Oswald Schmiedenberg
• Scientific understanding of drugs allows us to predict the
pharmacological effect
Why learn about pharmacology
• Zinberg – Drug, Set, Setting
• Health economics
• Epidemiology
• You may go on a diet/get old
• May need an antidote to a poison
• Drink or smoke/drugs
What is a drug – term of varied usage
• In medicine, it refers to any substance with the potential to prevent/cure
disease or enhance physical or mental welfare
• In pharmacology to any chemical agent that alters the biochemical
physiological processes of tissues or organisms – hence, a drug is a substance
that is, or could be, listed in a pharmacopoeia
• In common usage, the term often refers specifically to psychoactive drugs and
often even more specifically, to illicit drugs, of which there is non-medical use
in addition to any medical use. Professional formulations often seek to make
the point that caffeine, tobacco, alcohol and other substances in common non-
medical use are also drugs in the sense of being taken at least in part for their
psychoactive effects
• A substance that is recognized or defined as a drug by the Food and Drug
Admin
Issues:
• Herbal remedies? E.g. St John’s Wort
• Foods that alter neurotransmitter levels e.g. Tryptophan in turkey
Sources of drugs:
• Plants
o Morphine
o Cannabis
find more resources at oneclass.com
find more resources at oneclass.com
o Cocaine
o Peyote
• Animals
o Insulin
o Heparin
• Minerals
o Magnesium sulfate
o Lithium
• Micro-organisms (bacteria and fungi)
o Penicillin
o Psilocybin
• Synthetics
o Methamphetamine
o Analgesics
Drug Info:
• Nomenclature
o Chemical name
o Non-proprietary name
o Proprietary name
• Use
• Dose
• Contraindications
• Precautions
• Side effects
• Interactions (valium then drink alcohol – interaction)
• Half-life (time it takes to become effective or be removed)
Therapeutic Index (therapeutic vs. lethal dosing)
• ED50 → dose which 50% of population found drug to be effective
o Therapeutic (intended) dosing
• LD50 → dose at which 50% of population found to be lethal (dies)
o Keep below this dose
• Calculated by drug potency → ability for drug to take effect (how much is
needed)
• And drug toxicity → potential to do irreversible harm to body functions
o Poisons or excessive amount of any substance
• Each drug has a ‘THERAPEUTIC INDEX’ (margin of safety)
o Difference between LD50 and ED50
How Drugs Work:
• Take dosage → then look at concentration in plasma → look at concentration
at site of action → effect takes place
• During this process, we lose some effectiveness
o Pharmacokinetics = what the body does to the drug → absorption,
distribution, metabolism, excretion
o Pharmacodynamics = what drug does to the body → drug/receptor
interaction
find more resources at oneclass.com
find more resources at oneclass.com
Pharmacokinetics:
• Absorption
o Drug properties → chemical properties (lipophilic), form of drug
(tablet, liquid)
o Person/situational factors → size, diet, consciousness
o Bioavailability → fractional extent of drug which reaches its site of
action (or biological fluid)
o Routes of drug administration → topical applications (transdermal and
eye), oral (first pass metabolism – must pass through liver), pulmonary
absorption (inhalants), injections (subcutaneous, intraperitoneal,
intramuscular, intravenous)
Routes of Administration
• ORAL
o Advantages
▪ Absorption pattern: variable
▪ Most convenient
▪ Economical
▪ Safe
o Disadvantages
▪ Need patient co-operation
▪ Not used for drugs that are poorly soluble, slowly absorbed,
unstable or extensively metabolized by liver
▪ Emesis due to irritation of gastric mucosa
▪ Drug metabolized by gut enzymes or high acidity in gut
▪ First Pass Metabolism
• SUBLINGUAL AND RECTAL
o Sublingual
▪ Can give to unconscious patients
▪ Good for high lipophilic drugs
▪ Dissolve quickly through mucosa to vena cava
▪ No first pass metabolism
o Suppository/enema (rectal)
▪ 50% will bypass liver
▪ Very good when patient cannot take drugs orally
▪ Irregular absorption
▪ Many drugs irritate rectal mucosa
• PULMONARY, MUCOUS AND TOPICAL
o Inhalation
▪ Utilizes gas exchange in lungs
▪ Very rapid absorption due to vast surface area of lungs
▪ Good for pulmonary illnesses e.g. asthma
o Mucous membrane
▪ Nasal, vaginal, colon
▪ Absorbed by mucous membrane
▪ Bypasses first pass metabolism
▪ Bypasses gastric juices
▪ Good for local effects (e.g. decongestants)
o Topical
▪ Transdermal
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Hippocrates and this formed the basis for modern pharmacology . Father" of modern pharmacology = oswald schmiedenberg: scientific understanding of drugs allows us to predict the pharmacological effect. Why learn about pharmacology: zinberg drug, set, setting, health economics, epidemiology, you may go on a diet/get old, may need an antidote to a poison, drink or smoke/drugs. What is a drug term of varied usage. In medicine, it refers to any substance with the potential to prevent/cure disease or enhance physical or mental welfare. In pharmacology to any chemical agent that alters the biochemical physiological processes of tissues or organisms hence, a drug is a substance that is, or could be, listed in a pharmacopoeia. In common usage, the term often refers specifically to psychoactive drugs and often even more specifically, to illicit drugs, of which there is non-medical use in addition to any medical use. St john"s wort: foods that alter neurotransmitter levels e. g. tryptophan in turkey.
