pharmacology

1. PHARMACODYNAMICS

2. PHARMACODYAMICS
• Pharmacodynamics is the study of how drugs produce effects on living
individuals. Drug is said to have an effect if perceptible changes in a
biologic system can be obtained.

3. DRUG ACTIVITY
• A measure of the physiological response that a drug produces. A less active
drug produces less response, and a more active drug produces more
response.
• It is the Ability of the drug to combine with components of the cell
membrane or with internal components of the cell to cause alteration in cell
function.
http://www.medterms.com/script/main/art.asp?articlekey=3115

4. BASED ON THE DRUG BROUGHT IN THE
LAB, WHAT IS THE EFFECT OF THE
DRUG?
• Mefenamic acid is a non-steroidal antiinflammatory drug used to treat pain
including menstrual pain.

5. EXPLAIN THE MECHANISM OF ACTION
OF THE ABOVE DRUG.
• Mefenamic acid is a competitive inhibitor
of COX-1 and COX-2, which are
responsible for the first committed step in
prostaglandin biosynthesis. Decreasing the
activity of these enzymes thus reduces the
production of prostaglandins, which are
implicated in inflammation and pain
processes.

6. HOW CAN THE DRUG ACTION BE
IDENTIFIED.
• It is important to distinguish between actions of drugs and their effects.
Actions of drugs are the biochemical physiological mechanisms by which
the chemical produces a response in living organisms. The effect is the
observable consequence of a drug action.

7. HOW CAN THE DRUG ACTION BE
IDENTIFIED.
Types of drug action:
Stimulation
• Stimulating drugs increase the activity of specific cells. (Ex. Caffeine
stimulates cortical activity; epinephrine stimulates the effectors cells
innervated by adrenergic fiber.). No anatomic lesions are produced and
ordinarily the tissue recovers function after sufficient rest.
Depression
• Drug depression decreases the activity of specialized cells. (Ex. Barbiturate
depress the central nervous system, Codeine depresses the cough center in
the medulla). The diminished function, characteristic of the action of
depressive drugs, is ordinarily a reversible process as the effective dose is
metabolized

8. HOW CAN THE DRUG ACTION BE
IDENTIFIED.
Irritation
• Drug Irritation refers to the action of drug on the nourishment, growth, and
morphology of the cell. Varying degrees of irritation may be induced in all kinds of
tissue. Mild irritation may be used to stimulate activity of tissue. Excessive doses
sometimes result in intestinal bleeding, which is evidence of the irritating action of
the drug.
Chemotherapy
• Chemotherapeutic drugs are administered to attenuate or kill pathogenic
organisms without toxicity to the host. These drugs possess specific toxicity for the
invading pathogen.
Jones Meyer J. Veterinary Pharmacology and Therapeutics, 1957

9. GIVE EXAMPLE OF HOW DRUGS HAVE
BEEN DISCOVERED
ASPIRIN
• Hippocrates was left historical records of pain relief
treatments, including the use of powder made from
the bark and leaves of the willow tree to help heal
headaches, pains and fevers.
• 1829, scientists discovered that it was the compound
called salicin in willow plants which gave you the pain
relief.

10. GIVE EXAMPLE OF HOW DRUGS HAVE
BEEN DISCOVERED
ASPIRIN
• Henri Leroux had extracted salicin, in crystalline form
for the first time, and Raffaele Piria succeeded in
obtaining the salicylic acid in its pure state.
• The problem was that salicylic acid was tough on
stomachs and a means of 'buffering' the compound
was searched for.

11. GIVE EXAMPLE OF HOW DRUGS HAVE
BEEN DISCOVERED
ASPIRIN
• 1853, Gerhardt neutralized salicylic acid by buffering it
with sodium (sodium salicylate) and acetyl chloride,
creating acetylsalicylic acid. Gerhardt's product
worked but he had no desire to market it and
abandoned his discovery.
• 1899, a German chemist named Felix Hoffmann, who
worked for a German company called Bayer,
rediscovered Gerhardt's formula. Felix Hoffmann made
some of the formula and gave it to his father who was
suffering from the pain of arthritis.

12. GIVE EXAMPLE OF HOW DRUGS HAVE
BEEN DISCOVERED
ASPIRIN
• The folks at Bayer came up with the name Aspirin, it
comes from the 'A" in acetyl chloride, the "spir" in
Spiraea ulmaria (the plant they derived the salicylic
acid from) and the 'in' was a then familiar name
ending for medicines.

13. DISCOVERIES OF NEW VETERINARY
DRUGS
PALLADIUM
• Palladia (toceranib phosphate) was the first
FDA-approved antiangiogenic and
antiproliferative cancer treatment
specifically for dogs.
• Manufactured by Pfizer and was released for
use by veterinary oncologists in 2009 for the
treatment of Patnaik grade II or III, recurrent
cutaneous mast cell tumors with or without
regional lymph node involvement in dogs.
• It has been a remarkable adjunct for the
treatment of canine mast cell tumors (MCT)

14. DISCOVERIES OF NEW VETERINARY
DRUGS
PALLADIUM
• Palladia is a receptor tyrosine kinase (RTK)
inhibitor. Inhibition of RTKs on endothelial
cells, pericytes, and tumor cells disrupts
multiple processes necessary for tumor
growth.

15. MECHANISM OF ACTION OF ANY
DRUGS UNDER VPHAR200
PHENOBARBITAL
• Phenobarbital acts on GABAA receptors, increasing
synaptic inhibition. This has the effect of elevating
seizure threshold and reducing the spread of seizure
activity from a seizure focus. Phenobarbital may also
inhibit calcium channels, resulting in a decrease in
excitatory transmitter release. The sedative-hypnotic
effects of phenobarbital are likely the result of its
effect on the polysynaptic midbrain reticular
formation, which controls CNS arousal.
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