Lecture 7 Flashcards
State clinical usefulness of drug that stimulate GI motility
- In Gastroesophageal reflux disease, if it can increase lower esophageal sphincter pressure.
- In gastroparesis & postsurgical gastric emptying delay, if it can improve gastric emptying.
- For postoperative ileus or chronic intestinal pseudo-obstruction.
- For treatment of constipation, if it enhance colonic transit.
What are the common causes of GI disorder (constipation) ?
- dietary factor
- lack of exercise
- elderly person
- pathologic condition
What is the prokinetic agent
Drug that increases GI tract motility without evacuation
what are the example of prokinetic agent
- metoclopramide
- domperidone
- cisapride
- parasympathomimetics
- motility like agents
WHICH PROKINETIC AGENT IS DOPAMINE RECEPTOR ANTAGONIST?
- metoclopramide
- domperidone
what are the actions of metoclopramide and domperidone?
*blocking central dopamine receptors in the chemoreceptor trigger zone, they produce an antiemetic action *increase contractions in the stomach and enhance the tone of the lower esophageal sphincter, actions that combine to speed the transit of contents from the stomach
What is the difference between metoclopramide and domperidone in term of crossing BBB
Metoclopramide ca ross BBB meanwhile domperidone had limited passages to pass through BBB
What are the therapeutic uses of metoclopramide
● All vomiting EXCEPT motion sickness.
● Gastric hypomotility e.g. Diabetic gastroparesis.
● Emergency evacuation of stomach before surgery or
X-ray.
● Gastroesophageal-Reflux-Disease (GERD. Reflux
Esophagitis),
● Hiccup.
what is the doses for metoclopramide
10 mg 3-4 times/day Orally, Rectally. IM & IV.
what are the side effects of metoclopramide
●Gastrointestinal upset
● Dizziness & nervousness.
● Extrapyramidal manifestations e.g. Parkinsonism &
ataxia.
● Hyperprolactinemia ~> Galactorrhea in females
what are the therapeutic uses of domperidone
- To increase motility
- hyperprolactinemia
what are the side effects of domperidone?
- Rarely extrapyramidal
- hyperprolactinaemia
- cardiac arrhythmias
what are the pharmacodynamics of cisapride?
1) Increase 5-HT4 receptors in enteric ganglia
2) Causes release of Ach
3) Gastric and colonic motility increases
State the four intestinal evacuants
- purgatives
- cleansing enema
- glycerin suppository
- smooth muscle stimulants
what is purgatives?
Drugs taken Orally to evacuate the bowel.
purgative can be divided to what?
- MILD(LAXATIVE) PURGATIVE
- POTENT(CATHORTIC) PURGATIVE
WHATS THE DIFFERENCES BETWEEN MILD AND POTENT PURGATIVES?
MILD-production of a soft formed stool over a period of 1 or more days
POTENT-prompt, fluid evacuation of the bowel, more intense
WHAT ARE THE THERAPEUTIC USES OF PURGATIVES
- Constipation
- Constipation
- Before operation & X-ray abdomen
- To avoid straining in some patients
WHAT ARE THE CLASSIFICATIONS OF PURGATIVES
- PHYSICAL PURGATIVES
- CHEMICAL(IRRITANT) PURGATIVES
PHYSICAL PURGATIVES CAN BE DIVIDED TO?
- BULK FORMING (LUMINALLY ACTIVE AGENTS)
- LUBRICANT (EMOLLIENT)
- SURFACTANT ( SURFACE ACTIVE AGENTS)
CHEMICAL PURGATIVES CAN BE DIVIDED INTO?
- MILD IRRITANT
- MODERATE IRRITANT
- SEVERE IRRITANT
WHAT ARE THE ACTIONS OF BULK FORMING PURGATIVES?
-They ↑ bulk of gastric & intestinal contents → Stretch
of wall → Reflex peristalsis.
-They act on BOTH small & large intestine.
WHAT ARE THE ONSET OF ACTIONS OD BULK FORMING PURGATIVE?
-1-3 hours
● Taken in the
morning
WHAT ARE THE EXAMPLE OF BULK FORMING PURGATIVES?
- FOOD
- METHYL CELLULOSE
- SALINE PURGATIVES
- PLANTAGO SEEDS AND AGAR
- LACTULOSE (DUPHALAC SYRUP)
WHAT ARE THE ACTIONS OF LUBRICANT PURGATIVE?
1. Synthetic mineral Not absorbed orally. ”emollient” 2. Softens & lubricates hard fecal masses & mucosa of large intestine. 3. Useful in Chronic Constipation.
WHAT IS THE ONSET OF ACTION OF LUBRICANT PURGATIVE?
● 8-10 hours
WHAT ARE THE DISADVANTAGES OF LUBRICANT PURGATIVES?
1. ↓↓Absorption of fat-soluble vitamins (A, D, E & K) 2. ↓↓Absorption of other drugs e.g. Oral Contraceptives. 3. Uncontrolled leakage from anal sphincter. 4. If absorbed orally → Foreign body reaction in liver. 5. If it reaches the lung → Lipid pneumonia.
WHAT ARE THE ACTIONS OF SURFACTANT PURGATIVES?
1. Lowers surface tension of hard fecal masses 2. →facilitate penetration of water to stool 3. → Wetting & softening.
WHAT ARE THE DISADVANTAGES AND CONTRANDICATIONS OF CHEMICAL PURGATIVES?
- Colic, diarrhea & dehydration → Add small doses of Atropine or Hyoscine.
- ↓↓ Absorption of nutrients & drugs.
- Pelvic congestion:
a- Menstruation → Dysmenorrhea.
b- Pregnancy → Abortion. - May be excreted in milk → Affect suckling baby.
WHAT ARE THE TYPES OF ENEMATA?
- RETENTION ENEMATA
- EVACUANT ENEMATA
WHAT ARE THE DIFFERENCES BETWEEN RETENTION AND EVACUANT ENEMATA
Retention Enemata ● Small volume ● Low head pressure ● non-irritant Evacuant Enemata ● Large volume ● High head pressure ● Mild irritant
WHAT ARE THE PHARMACODYNAMICS OF LAXATIVE
● Stimulate peristalsis by irritate the smooth muscle of large intestine
● Alter water and electrolyte secretion
WHAT ARE THE CAUTIONS OF LAXATIVE?
● Children
● Pregnancy
● lactation
