1 59-291 section 1 introduction to pharmacology humans have been treating diseases with substances...
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59-291 Section 1
Introduction to Pharmacology
Humans have been treating diseases with substances around them for over 4000 yrs.
These “drugs’ were chosen empirically (based on experience).
The science of pharmacology is ~150 yrs old.
This is because the knowledge of the biochemical and physiological mechanisms by which drugs produce their physiological effects has been gained in the recent past.
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• Phase I: Superstition and Experience (Empiricism)• Phase II: Using plants/animals/ minerals to treat
diseases– Greeks; e.g. Dioscorides: described 600 plants– Islamic physicians; e.g. Avicenna, Razi: Herbal
medicine – Herbal medicine is still being practiced in many areas
• Phase III: Scientific – Understanding physiopathology of diseases– Rational for using drugs– Isolation of pure drug compounds from natural sources;
e.g. Morphine from Opium
Pharmacology- The science concerned with the interaction of chemical substances with living cells, tissues and organisms and the mechanisms by which drugs counteract the manifestations of disease or affect fertility.
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Pharmacology
Pharmacokinetics
Dose of Drug [Drug] in Target organ Over time
Absorption
Distribution
Biotransformation
Excretion
Pharmacodynamics
Mechanism & Magnitude of drug effect
Receptor Binding
Signal Transduction
Physiologic Effect
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Toxicology- Science of poisons and toxicity i.e. the harmful effects of drugs
- dose X drug therapeutic
- dose >X drug becomes toxic
-this might also be caused by drug interactions
Pharmacotherapeutics- The science concerned with the use of drugs in the treatment of disease.
-explaining the molecular mechanism for the effect of drug on the body as well as the relationship between dose and drug response (Dose-response curves)
-Clinical trials: used to determines the efficacy and safety of drug therapy in human subjects
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More Definitions
Pharmacy- Profession concerned with the preparation, storage dispensing and proper utilization of drug products.
Pharmacognosy- Isolation and characterization of drugs from natural sources including: Plants, animal tissues, microbes, and minerals
Medicinal Chemistry- Design and chemical synthesis of drugs
Pharmaceutical chemistry (Pharmaceutics) - concerned with the formulation and chemical properties of pharmaceutical products,
dosage form of drugs; tablets, capsules, liquid solutions, and aerosols
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Drug sources and preparation• Drug- (fr. Drogue- dried herbs), medication,
medicament: Substance administered to humans and animals for diagnosis or treatment of disease
• Natural sources of drugs: – Plants: Alkaloids >>Morphine– Microbes: Antibiotics >> Penicillin,
streptomycin– Animal tissues: Hormones>> growth hormone – Minerals: Lithium (Psychotherapy)
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Synthetic drugs- Although a drug is derived from natural sources, today it is more practical to synthesized in a laboratory.
-alterations are made on the naturally found structure of the drug to improve its effect and to improve the finances of pharmaceutical companies
Structure function relationships- (a relationship between the chemical structure and the pharmacologic activity)
guide the discovery of new drugs
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Recently chemists have developed
computer programs to facilitate the design of
new drugs. These programs help design
chemicals that fit to the 3-D conformation of
the receptor.
-led to the discovery of HIV protease inhibitors, ACE inhibitors etc.
Drug Preparations- What are the differences?
Crude-
Pure-
Phamaceutical-
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Figure 1-2 Types of drug preparations. A crude drug preparation retains most or all of the active and inactive compounds contained in the natural source from which it was derived. After a pure drug compound (e.g., morphine) is extracted from a crude drug preparation (in this case, opium), it is possible to manufacture pharmaceutical preparations that are suitable
for administration of a particular dose to the patient.
Drug Preparations•Crude drug preparations
•Drying, pulverizing•Extraction; Alcohol, hot water>Coffee, Tea, Opium
•Pure drug compounds•Morphine, Insulin
•Pharmaceutical preparations
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Pharmaceutical preparations(dosage forms)
• Suitable for administration of specific dose of a drug to a patient
• Tablets and capsules– Ingredients; fillers, lubricants, adhesives,
disintegrants– Enteric coating: disintegrates in alkaline
intestine– Sustained-release products
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Sustained release or extended release products
What are the 2 methods that extend the release of a drug?
•Controlled diffusion>> rate controlling membrane
•Controlled dissolution>> inert polymers
Transdermal patches-
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• Solutions and suspensions– Formulated for oral, parenteral administration – Convenient method for pediatrics– Syrups: Sweetened aqueous solutions– Elixirs: Sweetened alcoholic solutions
• Skin patches• Aerosols: respiratory disorders
– Nasal spray
• Ointments, creams – Topical application on skin/mucous membranes
• Lotions: – oil in water emulsion; to treat dermatologic conditions
• Suppositories: – Drugs inside a solid base that melts at body temperature
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Routes of drug administration• Enteral
– Sublingual/buccal
– Oral PO (per os)
– rectal
• Parenteral– Intravenous
– Intramuscular, subcutaneous
– Intrathecal
• Transdermal• Inhalation• Topical
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Drug names
• Chemical
• Nonproprietary (generic)
• Proprietary, trade name, brand name