Pharmacology lecture outline
V. Definition and properties.
A. A drug is a nonfood chemical that enters body and alters a
biological process
(need not be psychoactive). This isn't a perfect definition.
B. classification of drugs, there are lots of ways to do
this, we will classify drugs by action on nerve cells.
C. Main effects and side effects. (All drugs are dirty
drugs).
VI. Classification
A. sedatives
1. alcohol
2. barbiturates
3. benzodiazepines
B. misc: marijuana and nicotine
C. opiates (problem with definition of narcotics)
D. stimulants
E. Antidepressants
F. antipsychotics
VII. Pharmacokinetics: how drugs are distributed in body as function
of time. Drugs must get from administration site to blood and from
blood to brain.
A. lipid solubility is most important factor in absorption.
Don’t worry about the discussion of drug ionization from the bottom of
p 14 through the first column of pg. 16. You don’t need to understandd
Fig. 1-6.
1. Most drugs have some water solubility and some fat solubility,
but one is usually greater than the other.
B. IV: effects are rapid.
1. may be necessary if patient cannot take drug in another form
2. permits accurate control of dose.
3. problem: needles must be sterile
4. rapid action makes it difficult to counteract overdose.
C. Inhalation: also very fast, especially for fat soluble drugs.
1. anesthesia
2. Nicotine and THC are in particles; dissolve when hit wet
membranes of lungs and are absorbed into blood. particles
cannot be excreted by lungs; so these drugs may injure
epithelium.
D. Mucous membranes: cocaine, chewing tobacco
E. Skin patches: constant levels
F. Oral: most complex
1. absorb from stomach or intestine. Must be absorbed across
wall of stomach or intestine into the blood. Crossing of cell
membranes depends on fat solubility.
2. Basic drugs are not fat soluble in stomach, so are poorly
absorbed orally.
3. Some drugs, e.g., insulin will be destroyed by enzymes in
digestive system so can't be used orally.
VIII. Drug has to get into the blood, then has to get out of the blood
and into the brain.
A. Only the amount in the blood is available to the brain.
B. brain has to compete with fats.
C. When first take a drug, some is stored in fat as blood goes
through fat tissue.
D. Drug stored in fat is not immediately available to brain
E. As drug is metabolized by liver, blood is depleted and more
moves from fat to blood. So drugs that are extremely fat soluble have very
slow time course of action-marijuana.
F. Blood brain barrier
1. capillaries
2. astrocytes
IX. Excretion
A. Drugs are metabolized by liver until they are water soluble
1. liver enzymes can be induced
2. metabolites can be long lasting: accounts for the ability
to detect mj for 30 days after use.
3. half-life
4. Don’t memorize fig 1-9. You need to know the names of the
enzymes involved in metabolism of common drugs, but you do not need to
know the structures of molecules.
B. Then are eliminated by kidneys. You need to understand
the function of the kidneys in drug excretion, but you don’t ned to memorize
the names of all the parts.
C. understanding of excretion is important in treating overdose.
Can manipulate the chemistry of urine to excrete drugs faster. This
concept is used to treat barbiturate overdose.
X. Descriptions of drug action:
A. dose-response curve, potency, effectiveness, safety (therapeutic
index) LD50/ED50
B. You should understand the point of Figs. 1-10, 1-11, and 1-12
but you don’t need to memorize each curve.