GIT Pharmacology

Question 1

How many thick muscles does the stomach have and name them

Answer 1

Oblique muscle layer
Circular muscle layer
Longitudinal muscle layer

From inside to outside

They’re involved in the peristaltic action

Question 2

Name the parts of the stomach

Answer 2

The sphincters

Pyloric sphincter
Oesophageal sphincter
Rugae (where the secretory cells of the stomach are)

Question 3

When you cut a section through the stomach name the layers of the stomach coming from the outside and name the layers of cells that line the stomach in the rugae

Answer 3

Submucosa

mucosa

Muscularis

Cells that line the stomach internally:
The  mucous surface cell
Mucous neck cell
Parietal cell
Chief cell
Enteroendocrine cells

Question 4

What are the functions of the cells that line the stomach

Answer 4

Mucous surface cell:
Secrete mucus

Mucous neck cell:
Secrete mucus

Parietal cell:
Secretes HCL
And intrinsic factor

Chief cell:
Secretes pepsinogen and gastric lipase

Enteroendocrine cell:
Secretes gastrin

Question 5

Another name for chief cell and enteroendocrine cells are called respectively?

Answer 5

Zymogenic cells

G cells

Question 6

What is the pH of HCL

Answer 6

1-2

Question 7

Importance of the stomach secretions

Answer 7

The mucus forms a protective barrier against corrosive secretions

Hydrochloric acid converts pepsinogen from chief cell to pepsin(pepsin is involved in digestion)
–
Intrinsic factor-absorption of vitamin B12 for RBC production (even if you eat lots of vit b12 foods without the intrinsic factor it won’t be absorbed)
–
The acid and enzyme converts food into a thick semi-solid paste called chyme
–
Gastrin hormone (G cell)
»release more gastric juice
»increase gastric motility
-relax pyloric sphincter
»constrict oesophageal sphincter preventing re-entry
(When food enters the oesophageal sphincter is constricted to prevent reflux and pyloric is relaxed for food to move into the small intestine)

Question 8

What is the mucosal defense against acid and enzyme attack:

Answer 8

1. The mucus barrier (500 m thick),
2. a mucus matrix into which bicarbonate ions are secreted to produce a buffering gradient.(acts as a buffer as in base acid reaction to neutralize HCL)

3.The surface epithelium, which requires prostaglandins E2 and I2 synthesized by the gastric mucosa,
a.stimulate mucus and bicarbonate secretion,
b.decrease acid secretion and cause vasodilatation,
• all of which serve to protect the stomach against damage.(the prostaglandins do that)

Question 9

NSAIDS which inhibit prostaglandin (PG) synthesis will
decrease the protective barrier
True or false and why

Answer 9

True

They inhibit cyclooxygenase (Cox)

In case of tissue injury membrane phospholipids are acted on by phospholipase
This converts membrane phospholipids toarachnid onset acid and these are converted to prostaglandins by Cox 2
This causes pain ,inflammation. This only comes when you’re injured

In the system there’s constitutive prostaglandins secreted in the absence of injury by Cox 1

NSAIDS usually inhibit Cox cuz the NSAIDS used are non selective and inhibit both Cox 1 and Cox 2 and causes ulcer when used for a long time so the selective Cox inhibitors are to be used(celecoxib)(check spelling)

Question 10

What is peptic ulcer and what can it lead to if care is not taken

Answer 10

Peptic ulceration results from a breach in the mucosa lining of the alimentary tract caused by acid and enzyme attack.

•Unprotected mucosa rapidly undergoes auto-digestion(pepsin will digest the proteins in the surface lining of the stomach (enzyme attack))leading to a range of damage:
–Inflammation or gastritis
–Necrosis
–Haemorrhage
–Perforation as the erosion deepens(can cause leaking from stomach into peritoneum and that section of the stomach affected could be taken off causing a short transit time for food)

Note: Gastric and duodenal ulcers differ in their location but
present with similar symptoms and are treated on similar
principles.

Question 11

What happens in GERD or GORD

Answer 11

When food is eaten and gets into the stomach there’s so much intrabdominal pressure so the food tries to come out. The lower oesophageal sphincter (los)closed to prevent food from coming out.
In some people the los is not strong enough to prevent the food from coming out.the stomach is lined w mucus to oreotect it from the corrosive substances but the oesophagus is not lined w that mucus so when the food mixed with HCL and enzymes is refluxed or comes up there is inflammation of the oesophageal lining and is felt as heartburn
It is not to be mistaken with a cardiovascular problem or cardio chest pain

Question 12

What are the main causes of GORD

Answer 12

Loss of tone

Intraabdominal pressure caused by weight gain

Question 13

Drug management of GORD is similar to that of acid-related disorders
True or false
•

Answer 13

True

Question 14

Name three conservative treatment options of GORD

Answer 14

Conservative treatment options:
–Weight loss
–Raising the head of the patients bed
–Excessive smoking should be avoided

Question 15

In three short sentences name the pathogenesis of PUD

Answer 15

-Increased hydrochloric acid secretion

●Inadequate mucosal defence against gastric acid

●Infection with gram-negative Helicobacter pylori

NB- know the cause of the PUD before you treat it

Question 16

What are the four aims of treating PUD ,how is gastric acid secretion neutralized, how is mucosal resistance increased ?

Answer 16

To reduce gastric acid secretion with

Neutralizing secreted gastric acid secretion with Antacids such as
•
Increase mucosal resistance to acid-pepsin attacks with
Misoprostol or chelates(Bismuth chelate reduces mucosal damage or strengthens or repairs the mucosal layer)

•Eradicating H.pylori

Question 17

How does gastric acid secretion occur and how is it reduced

Answer 17

Gastrin is released by G cells and this activates gastrin receptors on the mast cells to activate histamine and histamine activated histamine receptors on the parietal cells to cause Hplus release and the gastrin also activated gastrin receptors on the parietal cells to cause the HPlus release

Proton pump inhibitors to stop the release of Hplus
»H2 antagonists
»Muscarinic receptor antagonists

Question 18

How does H pylori cause PUD and how is it eradicated

Answer 18

H pylori causes increased gastrin release by the G cells

Gastrin can directly activate the gastrin receptors on parietal cells and can also activate gastrin receptors on mast cells causing release of histamine causing the activation of histamine receptors on parietal cells causing release of Protons and chlorides

When the test is done is Hpylori is involved
Triple therapy is used :
One proton pump inhibitor and two antibiotics namely metronidazole and amoxicillin or metronidazole and clarithromycin or amoxicillin and clarithromycin. Takes a week or two to work

Or Quadruple therapy:
One proton pump inhibitor ,two antibiotics and bismuth chelate
More effective than triple therapy and takes shorter time to work like three days or one week

Question 19

What system does the parietal cell use to cause the release of H plus and what drugs inhibits it,what’s the mechanism of action , route of administration,indications ,adverse effects ,contraindications and the function of clopidogrel

Answer 19

Proton pump or Hydrogen potassium ATPase

It pumps protons

Omeprazole,Iansoprazole ,Esomeprazole,Rabeprazole,Lansoprazole
They are proton pump inhibitors
Mechanism of action: They inactivate the ATPase
And cause irreversible inhibition of the hydrogen /potassium ATPAse
Route of administration- oral and Occasionally Iv

Indications-Indications: short term treatment of peptic ulcers, eradication of H. pylori

• Adverse effects: GI upsets, nausea, headaches, PPIs may increase the risk of fractures, particularly if the duration of use is 1 year or greater
• Contraindications: PPIs(proton pump inhibitors may decrease the effectiveness of clopidogrel (used in place of aspirin at a low dose of 75 milligram for its anti platelet activity and is given to people at risk of stroke or thrombosis also in case some people can’t take aspirin due to some disease they take clopidogrel)because they inhibit CYP2C19 and prevent the conversion of clopidogrel to its active metabolite.

Question 20

When a certain mechanism is used and brings in Chloride what does it take out and later chloride is taken out with what

Answer 20

Bicarbonate

It’s taken out with potassium

Question 21

Name the receptors on the parietal cell

Answer 21

Gastrin receptors(G receptors)
Histamine H2 receptors
Muscarinic receptors
Prostaglandin receptors(PGE2)(the prostaglandins inhibit the release of H plus from the parietal cell or decrease the release of Hplus and Chloride

Question 22

Where is histamine released from and which drugs inhibit histamine receptors ,mechanism of action,route of administration,indications,adverse effects,contraindications

Answer 22

Mast cells

Cimetidine (Tagamet)(it is a hepatic enzyme inhibitor meaning it stops the metabolism or inactivation of warfarin ,phenytoin)
Ranitidine (Zantac)
Famotidine
Nizatidine

They are histamine H2 receptor antagonists

Mechanism of Action: Competitively block the action of histamine on the parietal cells by antagonizing H2 receptors.

• Route of administration: oral and IV
• Indications: Treatment of peptic ulcer and GORD
• Adverse effect: Diarrhoea, dizziness, muscle pains, alopecia, transient rashes, confusion in the elderly and hypergastrinaemia,
• Cimetidine causes low sperm count due to its anti-androgen effects, gynaecomastia & impotence due to its modest affinity for androgen receptors.

•Contraindications: Cimetidine (hepatic enzyme inhibitor) not given to patients stabilized on warfarin, phenytoin and theophylline(given to asthmatic patients).(these three drugs have narrow therapeutic index)

Question 23

How does vagus nerve cause the release of protons and chloride ,what drugs inhibits the muscarinic receptors,mechanism of action,route of administration,indications and adverse effects

Answer 23

Vagus nerve connects stomach to brain so when you sense food the vagus nerve activates themuscarinic receptors on the mast cells and activates the muscarinic receptors on the parietal cells using acetylcholine

Muscarinic receptor antagonists

•Examples: Atropine, pirenzepine, propantheline, dicyclomine (dicycloverine)

• Mechanism of Action: (The main effects of parasympathetic activity on the GIT are increased motility and increased secretory activity).
• Inhibition of parasympathetic activity, causing relaxation of GI smooth muscle may be of value in peptic ulcer since the condition may be accompanied by increased muscle spasm and reduces secretions of HCL
• Route of administration: oral or I.M.
• Indications: As adjuncts in the management of peptic ulcer(usually aren’t used but in some severe conditions they are used)

Adverse effects: Constipation due to reduced GI motility

Question 24

How does misoprostol work ,mechanism of action,route of administration,contraindications,adverse effects

Answer 24

It’s an analogue (similar)of the PGE2

It activates prostaglandins receptors to cause the inhibition of the release of Hplus

Mucosal strengthener
Examples: Misoprostol (cytotec)

• Mechanism of action: Synthetic analogue of PG E1, imitating the action of endogenous PGE2 and PGI2, thereby maintaining the integrity of the gastroduodenal barrier.
• It therefore promotes healing by exerting a direct action on the ECL cell (and possibly parietal cell), inhibiting the basal secretion of gastric acid. 
• It also increases mucosal blood flow and augments the secretion of mucus and bicarbonate
• Route of administration: oral
• Indications: Ulcer healing and prophylaxis with NSAID use(if you don’t have a choice to give non selective NSAID for use for a long time then you give misoprostol to prevent the person from getting ulcer)
• Contraindications: Hypotension, pregnant and breast-feeding women,causes abortion
• Adverse effects: Diarrhoea, nausea and abdominal pain

Ameritech is a combination of diclofenac and misoprostol to help the person
Can cause abortion

Question 25

Name three antacids and they’re mechanism of action in PUD ,indications,adverse effects and how the adverse effects occur and contraindications

Answer 25

Antacids Examples: Aluminium hydroxide, magnesium hydroxide ,sodium bicarbonate,tricilicate ,milk of magnesia They consists of alkaline either aluminum,magnesium or sodium salts and are used to 1. raise the luminal pH of the stomach to stop pepsin from working and 2.when it’s raised they neutralize the acid and 1.(part of 1)reduce the damaging effect of pepsin which is pH dependent Pepsin acts as a certain pH so it is not able to work for auto digestion to occur 3.These salts are heavy metals and can bind to pepsin to inactivate it Indications- symptomatic relief of GORD and ulcers Adverse effect-constipation and diarrhea ,belching,farting Antacids with aluminum cause constipation and those with magnesium cause diarrhea Nugel is a mixture of aluminum hydroxide and magnesium hydroxide to stop the diarrhea and prevent constipation Sodium bicarbonate with HCL forms salt,water and carbon dioxide causing people to fart and belch Not to be given to those with hypertension cuz of the salt It shouldn’t be within two hours of giving antibiotics and anti Fungals cuz antacids have heavy metals which form complexes w the drugs and inactivates the drugs

Question 26

What is the mechanism of action of sucralfate or carafate which is used to treat PUD,Indications,side effects,contraindications,

Answer 26

Can be used to prevent & treat PUD •It is a complex of aluminium hydroxide and sulfated sucrose, which releases aluminium in the presence of acid.  •The residual complex carries a strong negative charge which binds to cationic groups in proteins to forms sticky polymer in acidic environment (pH <4) and adheres to the ulcer site, forming a barrier to cover the ulcers in the stomach lining •This action restricts further caustic damage and stimulates mucosal prostaglandin and bicarbonate secretion from gastric mucosa. Contraindications-May bind with other drugs and interfere with absorption of fluoroquinolone antibiotics, theophylline, tetracycline, digoxin and amitriptyline. •Give approximately 2 hours before or after other drugs •Take on an empty stomach before meals so that the food won’t cover the ulcer sites Adverse effects: It may cause constipation, dry mouth, nausea, vomiting, headache

Question 27

Mechanism of action of bismuth compounds,adverse effects,Indications,contraindications

Answer 27

Two bismuth compounds are available: bismuth subsalicylate and bismuth subcitrate potassium •Bismuth coats ulcers and erosions, creating a protective layer against acid and pepsin. •It may also stimulate prostaglandin, mucus, and bicarbonate secretion. •Some activity against H. pylori •Should not be used repeatedly or for more than 2 months at a time •Can cause black stools and tongues, constipation •Prolonged usage of some bismuth compounds may rarely lead to bismuth toxicity, resulting in ataxia,headache,confusion,seizures

Question 28

Mechanism of action of alginates ,route of administration,indications,contraindications

Answer 28

Examples: Gaviscone ( is an alginate containing antacid) * Mechanism of action: Forms an impenetrable raft that floats on the surface of the gastric contents. The layer prevents gastric acid from refluxing into the oesophagus. * Route of administration: oral * Indications: useful in GORD * Contraindications: Well tolerated but no effect upon acid secretion or healing No serious side effects

Question 29

What is nausea and vomiting

Answer 29

Nausea –an unpleasant feeling in the upper abdomen and throat which usually precedes vomiting. –May be experienced without vomiting. Vomiting – Vomiting is the forceful evacuation of gastric contents through the mouth.

Question 30

The higher centers (cerebral cortex)are involved in critical thinking true or false

Answer 30

True

Question 31

CTZ and vomiting Centre are in the medulla oblongata true or false

Answer 31

True

Question 32

Labyrinth is divided into two name em

Answer 32

Cochlear that controls sound that gets to the brain Vestibular apparatus that is made up of fluid like mechanisms and control balancing Has a strong communication with the vomiting Centre

Question 33

Name the four mechanisms that cause vomiting

Answer 33

1.Disorienting motion (such as spinning around plenty)disturbs the labyrinth specifically the vestibular nuclei and this communicates to the vomiting Centre in the medulla 2. Unpleasant emotions or experiences or emotional experiences will communicate to the higher centers in the cerebral cortex and will communicate w the vomiting Centre in the medulla to cause vomiting 3. CTZ in the area postrema is triggered by toxins and drugs and when it is triggered it communicates w the vomiting Centre to cause vomiting by triggering the GIt muscles involved in vomiting to cause the forceful evacuation of gastric contents 4. (the periphery)Stimuli to the pharynx or stomach via the vagus nerve and nucleus of the solitary tract and this communicates w the vomiting Centre to cause vomiting

Question 34

Name the drugs that inhibit each of the four mechanisms that cause vomiting

Answer 34

1. Hyoscine,Atropine,Scopolamine that block M1 receptors Antihistamines such as promethazine,cyclizine ,meclizine ,cinnarizine to block H1 receptors(not to be mixed w H2 receptors in ulcer) 3. Domperidone ,metoclopramide,chlorpromazine,prochlorperazine, And they inhibit dopamine receptors (D2) 4.Ondansetron,dolasetron,granisetron,tropisetron, these are serotonergic receptor blockers in both CTZ and GIT

Question 35

What receptors are in both the vestibular nuclei and vomiting Centre,receptors in the GIT and GIT muscles ,receptors in the CTZ

Answer 35

``` H1recptors (histamine receptors) M1 receptors(muscarinic receptors) ``` 5-HT3(subscript 3)(serotonergic receptors) These are also found in the CTZ (D2)Dopaminergic receptors are also in the CTZ and found in the vomiting Centre as well I think

Question 36

You have to know what is causing the vomiting to give medication for it true or false

Answer 36

True

Question 37

Scopolamine can be used as prophylaxis in those who travel plenty and have vomiting issues true or false

Answer 37

True

Question 38

What is emesis and name one drug that is used for emesis

Answer 38

Inducing vomiting to rid the GIT of ingested exogenous toxins Emetic drugs •Ipechacuanha (from some kind of herbal formulation) – given as a liquid causes gastric irritation resulting in emesis.

Question 39

Name some antihistamine drugs,state the mechanism of action,route of administration,indications,adverse effects,caution

Answer 39

H1 receptor antagonists Examples: - cinnarizine, cyclizine, meclizine and promethazine –These are antiemetic antihistamines –Have little effect on nausea and vomiting induced by substances acting directly on the CTZ –Are however effective in motion sickness and vestibular disorders. Route of administration: cyclizine-oral, i.m, i.v; Cinnarizine-oral Indications: motion sickness, vestibular disorders Adverse effects: drowsiness, dry mouth, blurred vision Caution: use with caution in urinary retention

Question 40

Antipsychotics specifically the phenothiazines act on dopaminergic receptors ,muscarinic receptors,histaminic receptors and can be used to stop vomiting. Name some antipsychotic drugs,mechanism of action,route of administration,indications,adverse effects,contraindications and how the contraindications occur

Answer 40

Examples: Phenothiazines – chlorpromazine, perphenazine, , prochlorperazine and trifluoperazine * Mechanism of action: Numerous effects; They block dopaminergic, histaminic and muscarinic receptors. * Route of administration: Oral, rectal and intramuscular * Indications: Nausea, vomiting, vertigo, psychosis * Contraindications: May exacerbate Parkinsonian symptoms. Cuz in Parkinsons there’s motion or movement problems and motion is controlled mainly by dopamine and Ach is also involved . Dopaminergic neurons are destroyed so there a re few levels of dopamine. If you give antipsychotics they’ll block dopamine receptors reducing dopamine effects making things worse in the patient •Adverse effects: sedation, extrapyramidal symptoms including dystonias and tardive dyskinesia . These are symptoms of Parkinson’s •Other antipsychotics, such as haloperidol also act as D2 antagonists in the CTZ and can be used for acute chemotherapy-induced emesi Antipsychotics cross the blood brain barrier The CTZ is located outside the blood brain barrier

Question 41

Name dopamine antagonists,mechanism of action,route,indications,adverse effects,contraindications

Answer 41

Dopamine antagonists •Examples: Domperidone (Motilium); metoclopramide (Maxolon) * Mechanism of action: They block dopamine receptors in the CTZ. Their antiemetic effect is enhanced by promoting gastric emptying and small intestine peristalsis. * Route of administration: Metoclopramide-oral, i.m, i.v, Domperidone-oral, rectal * Indications: Nausea and vomiting * Cautions: * Metoclopramide produces a number of unwanted effects including disorders of movement (more common in children and young adults), fatigue, motor restlessness, spasmodic torticollis (involuntary twisting of the neck) and occulogyric crises (involuntary upward eye movements). * It stimulates prolactin release causing galactorrhoea and disorders of menstruation.(these drugs can be given to people who don’t produce milk I mean nursing mothers to stimulate the prolactin release ) * Domperidone does not readily penetrate the blood-brain barrier and is consequently less prone to produce central side effects

Question 42

Name some serotonergic receptor antagonists,mechanism of action,route,indications,adverse,contraindications

Answer 42

Selective 5-HT3 receptor antagonists * Examples: ondansetron, granisetron, tropisetron, palonosetron and dolasetron * Mechanism of action: Antagonism of 5-HT3 (serotonin) receptor in the CTZ is believed to be responsible for the antiemetic effects * Route of administration: oral, rectal, intramuscular, iv * Indications: Nausea & vomiting especially associated with cytotoxic therapy * Adverse effects: Constipation & headache

Question 43

Name three other classes of drugs that inhibit vomiting and examples of drugs under them

Answer 43

``` Cannabinoids –Nabilone (Synthetic cannabinol derivative) •Steroids –Eg. Dexamethasone •Neurokinin-1 antagonists –Aprepitant –fosaprepitant ```

Question 44

Name the four classes of drugs used for their effects on the GI motility

Answer 44

Motility stimulants –Antispamodics –Laxatives –Antidiarrhoeals

Question 45

What is the importance of motility stimulants and examples

Answer 45

These are agents that increase GI motility without a laxative effect and are used clinically for motility disorders such as: –Gastric stasis (slow stomach emptying) –Diagnostics e.g. Duodenal intubation •Examples: Domperidone and metoclopramide increase intestinal motility

Question 46

Name the classes of drugs used in antispasmodics ,examples in each class and the uses of antispasmodics

Answer 46

Antimuscarinics e.g. propantheline, dicycloverine (dicyclomine)(will worsen diarrhea) They reduce GIT motility To help stop spasms during period that causes pain (buscopan (drug) (hyoscine butyl bromide ) –Drugs acting directly on smooth muscle eg. Mebeverine, alverine, peppermint oil •Antispasmodics have smooth muscle relaxant properties, therefore useful as adjuncts for: –Non-ulcer dyspepsia(relax the muscles in ulcer to reduce pain kakra) –Irritable bowel syndrome –Diverticular disease

Question 47

Name examples of anitmuscarinics ,mechanism of actions,adverse effects,indications,contraindications ,route of administration

Answer 47

Antimuscarinics Example: propantheline, dicycloverine (dicyclomine) Mechanism of action: Inhibition of parasympathetic activity Causing relaxation of GI smooth muscle Route of administration: oral Indications: Non- ulcer dyspepsia, irritable bowel syndrome and diverticular disease. Contraindications: Antimuscarinic drugs relax the LOS therefore should be avoided in GORD, also myasthenia gravis(check this) Adverse effects: dry mouth, blurred vision, dry skin, tachycardia, urinary retention

Question 48

Name examples of drugs that act directly on the smooth muscle ,mechanism of action,indications,route,

Answer 48

Drugs acting directly on smooth muscle * Example: Mebeverine, alverine, Peppermint oil * Mechanism of action: Direct relaxants of smooth muscle * Route of administration: oral * Indications: irritable bowel syndrome, diverticular disease

Question 49

Name four causes of diarrhea and three causes of constipation

Answer 49

Constipation-reduced fluids,increased solids volume,decreased peristalsis(this can be due to drugs side effects example of such drugs are opioids,anticholinergics or antimuscarinics Diarrhea-malabsorption,osmoticimbalance or osmotic load(absorption relies on osmosis so if gastric contents do not allow for osmosis to occur so it’ll stay in the GiT and will have to come out in diarrhea) so the malabsorption and increased osmotic load or the osmotic imbalance will cause an increase in fluid volume causing diarrhea 2. Some antibacterials can induce diarrhea and some drugs can cause increased peristalsis causing diarrhea 3. Virus/bacteria(acute) can cause diarrhea due to the toxins they produce example cholera causing increased fluid secretion this increases fluid volume causing diarrhea 4. an underlying disease and when there’s anxiety can have an effect on the parasympathetic or enteric nervous system and this causes increased peristalsis causing diarrhea

Question 50

Drugs used in cases of diarrhea are called ?

Answer 50

Costives

Question 51

What are laxatives ,when are they given and what classes of laxatives are there

Answer 51

are drugs used to hasten transit time in the gut and encourage defecation. –They are useful to prevent undue straining at stool. Laxatives/purgatives may be given to: –To remove poisons from the alimentary canal –Prepare patients for radiological examination of the colon –Remove parasites from the body after anthelminitic therapy sometimes when you give dewormers they paralyze the bacteria o you take in laxative to make em get out –Empty the bowel before surgery Classification of laxatives –Bulk-forming laxatives eg. Bran, methylcellulose, Ispaghula husk –Osmotic laxatives eg. Lactulose and saline purgatives –Stimulant laxatives eg. Senna, danthron, bisacodyl, sodium picosulphate, castor oil –Faecal softners (lubricants) eg. Liqiud paraffin, docusate sodium

Question 52

Name examples of bulk forming laxatives ,mechanism of actions.,route of administration,indications,contraindications ,adverse effects

Answer 52

Bulk forming laxatives Examples; Bran, methylcellulose, Ispaghula husk Mechanism of action: They are fibres that absorb water and add up to the bowel contents thereby increasing the volume of non-absorbable solid residue in the gut, causing distending of the colon and stimulating peristalsis Route of administration: oral Indications: constipation Contraindications: intestinal obstruction, colonic atony, dysphagia Adverse effects: flatulence, abdominal distension, GI obstruction Note: adequate fluid intake is encouraged, onset may be several days

Question 53

Name examples of osmotic laxatives ,mechanism of actions.,route of administration,indications,contraindications ,adverse effects

Answer 53

Osmotic laxatives Example: Lactulose and saline purgatives(can be salt in water) Mechanism of action: –Poorly absorbed substances that increase the water content of the bowel by osmosis(there is drawing of water from the system into the GIT where the feces are –Lactulose, a semi-synthetic disaccharide not absorbed from the GIT. –Magnesium and sodium salts are poorly absorbed and can be osmotically active. Route of administration: oral Indications: constipation, Contraindications: intestinal obstruction,

Question 54

Name examples of stimulant laxatives,mechanism of action ,indications, adverse effects,contraindications

Answer 54

Stimulant laxatives Examples: – Senna, danthron, bisacodyl, sodium picosulphate, castor oil Mechanism of action: –Increase GI peristalsis and water and electrolyte secretion by the mucosa possibly by stimulating enteric nerves Route of administration: Oral and rectal Indications: –constipation and bowel evacuation prior to medical/surgical procedures Contraindications: –Intestinal obstruction Adverse effects: – intestinal cramps, possible damage to nerve plexi leading to deterioration of intestinal function and atonic colon. Danthron, potentially carcinogenic. •Note: Give stimulant laxatives for short periods only 7/22/2021 47

Question 55

Name examples of lubricants or (fecal softeners)laxatives,mechanism of action ,indications, adverse effects,contraindications

Answer 55

Lubricants (faecal softeners) Examples Faecal softners (lubricants) eg. Liqiud paraffin, docusate sodium Mechanism of action Promote defaecation by softening (Docusate sodium) and/or by lubricating (liqiud paraffin) faeces to aid their passage through the GI tract. Route of administration: oral, docusate sodium can be given rectally. Indications: constipation, haemorrhoids Contraindications: not in children less than 3 years Adverse effects: Prolonged use of liquid paraffin impairs the absorption of fat-soluble vitamin A and D Note: Prolonged use not recommended.

Question 56

Define diarrhea and it’s causes

Answer 56

Diarrhoea is defined as passage of frequent, loose, watery stools 3 or more times a day. Causes of diarrhoea: –Toxins –Food –Anxiety –Drugs (e.g. Penicillins, laxatives, NSAIDS) –Infections (amoebic dysentery, Typhoid, Cholera)

Question 57

Name the ways diarrhea is treated

Answer 57

Treatment of Diarrhoea There are four approaches to the treatment of severe acute diarrhoea: 1. Maintenance of fluid and electrolyte balance through Oral Rehydration Therapy (ORT). 2. Use of anti-microbial drugs 3. Use of opiate-like anti-motility drugs 4. Use of stool modifiers and adsorbents NB-make sure you know the cause of the diarrhea before you treat w 2,3 or 4 but1 is standard

Question 58

Which treatment of diarrhea is the first priority treatment ,what should it contain

Answer 58

ORT Should be the first priority in the treatment of acute diarrhoea •Standard ORT should contain: –NaCl –KCl –Sodium citrate –Glucose (in appropriate concentrations) IV rehydration therapy recommended if dehydration is severe. 7/22/2021

Question 59

What therapy for diarrhea is used when pathogens are confirmed to be the cause,what risks does it carry,acute diarrhea is usually self limiting true or false

Answer 59

Antimicrobial therapy is recommended only when a pathogen is identified or suspected. •Acute infectious diarrhoea is self-limiting •Note: Antibiotic therapy carries certain risks –Resistance –Destroying normal commensal flora –Overgrowth of Clostridium difficile - pseudomembranous colitis Antibiotic treatment is indicated in: •Severe Cholera or Salmonella typhimurium infection- Tetracycline * Shigella species infections - Ampicillin * Campylobacter jejuni - Erythromycin or Ciprofloxacin

Question 60

What does tetracycline,ampicillin and erythromycin or ciproflaxin

Answer 60

Severe Cholera or Salmonella typhimurium infection- Tetracycline * Shigella species infections - Ampicillin * Campylobacter jejuni - Erythromycin or Ciprofloxacin

Question 61

What treatment is given for diarrhea when you are sure no poison,pathogen is causing It,state the class of drugs it is in,mechanism of action ,indications,contraindications

Answer 61

Costives Class-Opiate-like anti-motility drugs Examples: Loperamide & Codeine,morphine causes constipation and is an opioid as well as heroine Mechanism of action: These act on opiate receptors in the myenteric plexus, which increases the tone and rhythmic contraction of the intestine, but lessens propulsive activity. (Decrease in propulsive activity leads to an increase in transit time and hence absorption of electrolyte. Overall effect is constipation. Loperamide and codeine also have an anti-secretory action) Route of administration: Oral Indications: As adjunctive therapy in some chronic diarrhoeal conditions. Have a limited role as an adjunct to fluid and electrolyte replacement in acute diarrhoea. Increase transit time of food Contraindications: Acute ulcerative colitis or antibiotic associated colitis. Not recommended for children. Adverse effects: nausea, vomiting, abdominal cramps, constipation, drowsiness 7/22/2021 53

Question 62

Name examples of stool modifiers ,mechanism of action, indications, contraindications

Answer 62

Stool modifiers/adsorbents Examples: Kaolin, chalk, charcoal, methylcellulose & pectin Mechanism of Action: Adsorption of toxins or coating and protecting the intestinal mucosa. They also add solid matter to the colonic contents and improve the consistency of the faeces. Route of administration: Oral Contraindications: Not recommended for acute diarrhoea Adverse effects: inhibit the absorption of other drugs

Question 63

Name five other classes of costives with examples

Answer 63

CONSTIPATION (COSTIVES) –Morphine and its congeners –Aluminium salts –Atropine and other antagonists of muscarinic receptors –Sympathomimetic drugs - Adrenaline, Ephedrine, Phenylephrine –Phenothiazines - Chlropromazine –Tricyclic anti-depressants – Amitriptyline & imipramine (central impairment of parasympathetic reflexes)

Question 64

What is IBd,the classification of IBD and four broad treatment of IBD

Answer 64

INFLAMMATORY BOWEL DISEASE (IBD) Fall into two categories, but share a number of features. Symptoms often relapse and remit and their aetiology remains unclear. Crohn’s disease: Affects the entire gut and inflammation occurs through out the full thickness of the bowel wall Ulcerative colitis: Affects only the large bowel and inflammation is limited to the bowel mucosa or a small part of the bowel Treatment involves: •Pharmacological * Psychological support * Correction of nutritional deficiencies * Surgical resection 7/22/2021 56

Question 65

What is the drug management of IBD and what is the aim

Answer 65

Controlling the inflammation and bringing about remission Drugs used include: •Glucocorticoids-have anti inflammatory properties * Aminosalicylates-have anti inflammatory properties * Immunosuppressives-suppress the immune system cuz inflammation is part of the immune response * Cytotoxics and antibiotics-

Question 66

Name examples of glucocorticoids,general mechanism of action(not in details), indications, contraindications, adverse effects

Answer 66

Glucocorticoids Examples: Prednisolone, budesonide, hydrocortisone,Dexacortine(check?) Mechanism of Action: They have anti-inflammatory effects Route of administration: rectal, enemas, suppository or foams in localized disease. Oral or i.v. in extensive or severe disease Indications: for acute relapses of IBD Contraindications: bowel obstruction or perforation or for long periods Adverse effects: Cushing's syndrome-obesity and ‘moon’ face, hyperglycaemia, hypertension,osteoporosis, muscle weakness and wasting, suppression of growth in children

Question 67

Name examples of aminosalicylates,general mechanism of action(not in details), indications, contraindications, adverse effects

Answer 67

Aminosalicylates Examples: Sulfasalazine, Mesalazine, Olsalazine sulfasalazine, broken down in the gut5-aminosalicylate (5-ASA) -and sulphapyridine which acts as a vehicle to transport the drug to the colon Mechanism of action: One proposed mechanism is the inhibition of prostaglandins, resulting in local anti-inflammatory effects in the colon. Mesalazine = 5-ASA Olsalazine = 2(5-ASA) Route of administration: oral, rectal Indications: maintenance therapy of IBD

Question 68

Name examples ofimmunosuppressive,cytotoxic,antibiotics ,general mechanism of action(not in details), indications, contraindications, adverse effects

Answer 68

Immunosuppressives, cytotoxics, and antibiotics Immunosuppressant azathioprine is used as an adjunct to other therapies when side effects of steroids are overwhelming. In addition, cytotoxic drugs e.g. methotrexate, the antibiotic metronidazole have all been used to modulate the disease process

Question 69

In treating diarrhea what isused to treat the travelers diarrhea

Answer 69

Agents that modify fluid and electrolyte transport Bismuth subsalicylate, used for traveler’s diarrhea, decreases fluid secretion in the bowel. Its action may be due to its salicylate compo- nent as well as its coating action