2. Basic definitions
Pharmacology is a biomedical science concerned with the
study of drug action.
Drug means any substance which exerts a physiological
effect on the cell, tissue, organ, or organism. Drug effect on
the body may be either positive or negative.
Medicine, means any chemical substance used to prevent,
treat, cure, or diagnose a disease in proper dose. Morphine is a
medication if used for analgesic purpose. On the other hand, if
it is used for recreational purposes, then it acts as a drug. All
medicines are drugs, not all drugs are medicines.
Dose means the amount of medicine taken
Dosage form means the physical form of the medicines
(solids, liquids, gas etc.)
3. Basic definitions
• Over the counter (OTC)medicine means those medicines for which the physician
prescription is not required. For examples, analgesics
• Analgesic means those medicines which are used for pain
• Antipyretics means those drugs which are used for fever
• Pharmacodynamics means the mechanism by which the drug exerts its effect. For
example, how aspirin work as analgesic.
• Pharmacokinetics means the movement of drugs in the body, including the
processes of absorption, distribution, biotransformation, and excretion.
• Drug source means the origin of drug (natural, semisynthetic, synthetic etc. natural
sources of drug are plants, minerals, animals, and microbes.
• Iontophoresis means a technique which uses an electric current to deliver a
medicine. Common uses for iontophoresis are to decrease inflammation, decrease
pain, decrease muscle spasm, decrease swelling and edema.
• Phonophoresis means the use of ultrasound to enhance the delivery of topically
applied drugs.
• Idiosyncratic means unexpected drug reaction
• Teratogenic means harmful effects of drugs on the fetus
• Synergism means when the combination of drugs increases the effects
• Antagonism means when the combination of drugs decreases the effects
4. Basic definitions
• Pharmacopoeia is an official publication, containing a list of medicinal drugs with their
effects and directions for their use. BP: British Pharmacopoeia. USP: United States
Pharmacopeia
5. • Active ingredient means biologically active substance which produce effect
• Efficacy means maximum effect that a drug can produce regardless of dose.
• Potency means amount of a drug that is needed to produce a given effect
6. • Bioavailability is the degree to which or the proportion of the drug that is available
to the site of action or target tissue to produce the desired effect.
• Half-life (t1/2) is the time taken by the plasma concentration of the drug to decrease
by 50%, or reach half of the original concentration
• Prophylactic agent is any drug that prevents a disease or illness from occurring
• Therapeutic effect : A drug is given to produce a desired effect on the body, either
to treat a disease or to relieve symptoms. This is referred to as a drug’s therapeutic
effect.
• Side effect is an unintended response to a drug
• Tolerance is a decrease in the pharmacological response to a drug that occurs with
continued administration
7.
8. Pharmacology of gastrointestinal drugs
Peptic ulcer disease: Peptic ulcer disease refers to sores in the lining of
the stomach or the duodenum.
Gastric ulcer means when the ulcer is in stomach
Common Causes
• Regular use of NSAIDs (aspirin, diclofenac
etc.)
•Bacteria (Helicobacter pylori)
Symptoms
•Burning pain in the middle or upper stomach
•Nausea or vomiting
•Weight loss
•Anemia
•Malena ( the condition in which the stool color
becomes black )
•Loss of apetite
9.
10. NSAIDs induce ulcers by suppressing gastric prostaglandin synthesis,
reduction of gastric mucosal blood flow.
Certain prostaglandins such as PGE2 and PGI2 inhibit gastric secretion and help
protect the stomach mucosa by stimulating gastric mucus secretion. Currently,
only misoprostol (Cytotec) is available for clinical use.
13. Drugs used peptic ulcer
Classification
• 1. Drugs which neutralize acid(Antacids): Antacids attempt to chemically neutralize
stomach acids. These drugs typically contain a base such as carbonate or hydroxide combined with
aluminum, magnesium, or calcium. The base combines with excess hydrogen ions (H) in the
stomach and thus increases the pH
14.
15. 2. Drug which provide a physical barrier
• Sucralfate (Carafate, Sulcrate). Sucralfate is a disaccharide that
exerts a cytoprotective effect on the stomach mucosa.
Sucralfate may form a protective gel within the stomach that
adheres to ulcers and shields them from the contents of the
stomach.
16. 2. Drugs which decrease acid secretion
a. Proton Pump Inhibitors b. H2 receptor blockers
17. Mechanism of action of PPIs
Gastric juice contains hydrochloric acid secreted by the parietal cells. Hydrogen ions
are generated within the parietal cell from dissociation of water. Hydrogen ion is
pumped out of the cell, into the lumen, in exchange for potassium through the
action of the proton pump.
PPI drugs inhibit the H, K -ATPase enzyme responsible for secreting acid from gastric
parietal cells of the stomach.
Common adverse
effects
headache
nausea
diarrhea
abdominal pain
fatigue
dizziness
constipation
18.
19. Mechanism of action of H2 blockers
Histamine stimulates specific receptors on stomach parietal cells to
increase gastric acid secretion. These histamine receptors are
classified as H2 receptors. H2 antagonists, or blockers, prevent the
histamine activated release of gastric acid.
Side effects:
• headache
• nausea
• diarrhea
• abdominal pain
• dizziness,
• Constipation
• Cimetidine has been associated with gynaecomastia (breast
enlargement in men)and anti androgenic properties.
20. Treatment of H. Pylori
bid: bis in die or two times a day
tid:ter in die (three times a day)
qid:quater in die( four times a day)
Stat: urgent
sos: si opus sit, if needed
21. How to prevent ulcer
• Take NSAIDs with meals or medications that protect your
stomach lining, if you need NSAIDs.
• Avoid or limit caffeinated drinks and alcohol.
• Refrain from smoking.
• Take steps to reduce the stress in your life.
