GI-DOC SOLEDAD

circular muscularis

longitudinal muscularis mucosa

Two types of muscle layers:

GASTROENTERIC REFLEX

GASTROCOLIC REFLEX

DUODENAL-COLIC REFLEX

CENTRAL REFLEXS

LOCAL REFLEXES:

GASTROENTERIC REFLEX

Stimulation of the stomach by stretching, the

presence of food, or cephalic stimulation (the

body's response to smelling, seeing, tasting, or

thinking about food) causes an increase in

activity in the small intestine. It is thought that

this prepares the small intestine for the coming

chyme.

GASTROCOLIC REFLEX

Stimulation of the stomach also causes

increased activity in the colon, again preparing

it to empty any contents to provide space for the

new chyme.

DUODENAL-COLIC REFLEX

The presence of food or stretching in the

duodenum stimulates colon activity and mass

movement, again to empty the colon for the new

chyme.

Swallowing

stimulated whenever a food bolus stimulates

pressure receptors in the back of the throat and

pharynx.

Vomiting

stimulated by the emetic zone that when

stimulated, initiates projectile vomiting.

Drugs used to Treat Gastroesophageal Reflux

Disease and Ulcer Disease

Antacids

Proton Pump Inhibitors

Gastrointestinal Protectants

Prostaglandins

Digestive Enzymes

DRUGS AFFECTING GI SECRETIONS:

Histamine-2 (H2) antagonists

Antacids

Proton Pump Inhibitors

Gastrointestinal Protectants

Prostaglandins

DRUGS USED TO TREAT GERD AND ULCER

DISEASE:

HISTAMINE-2 (H2) ANTAGONISTS

blocks the release of hydrochloric acid in

response to gastrin

ANTACIDS

interacts with acids at the chemical level to

neutralize them

PROTON PUMP INHIBITORS

suppress the secretion of hydrochloric acid into the lumen of the stomach

GASTROINTESTINAL PROTECTANTS

coats any injured area in the stomach to prevent further injury from acid

PROSTAGLANDINS

inhibits the secretion of gastrin and increases the secretion of the mucous lining of the stomach, providing a buffer.

cimetidine

famotidine

Nizatidine

Ranitidine

HISTAMINE-2 (H2) ANTAGONISTS DRUG LIST:

HISTAMINE-2 (H2) ANTAGONISTS

• H2 antagonists selectively block H2 receptors located on the parietal cells.

• Blocking these receptors prevents about 70% of

the hydrochloric acid release from the parietal

cells.

• Also decreases pepsin production by the chief

cells.

• These drugs are used in the following conditions:

• Short-term treatment of an active duodenal

ulcer or a benign gastric ulcer

Cimetidine

Absorption:

Peak levels in 1-1.5 hours

Distribution:

Crosses the placenta and enters breastmilk

Metabolism:

• Liver;

• Slows metabolism of many other drugs - same

metabolizing enzyme

• Half-life - 2 hours

Excretion:

Urine

HISTAMINE-2 (H2) ANTAGONISTS

• Treatment of pathological hypersecretory

conditions such as Zollinger-Ellison syndrome

• Prophylaxis of stress-induced ulcers and acute

upper GI bleeding in critical patients

• Treatment of erosive gastroesophageal reflux

• Relief of symptoms of heartburn, acid

indigestion, and sour stomach

Cimetidine

Contraindication:

Allergy to ANY of this class

Use with caution:

• Pregnancy and Lactation

• Hepatic or renal dysfunction

• Prolonged or continual use of these drugs may

mask serious underlying conditions

Cimetidine

ADVERSE EFFECTS:

• GI effects of Diarrhea - diarrhea or

constipation

• CNS - dizziness, headache, somnolence,

confusion, o even hallucinations (H2 receptors in

the CNS)

• cVs - cardiac arrhythmias and hypotension (H2

receptors in the heart)

• Gynecomastia (cimetidine)

• Impotence

Warfarin anticoagulants

Phenytoin, Beta-adrenergic blockers

Alcohol

Quinidine, lidocaine, theophylline, chloroquine

BZD, TCA, procainamide, Carbamazepine

Cimetidine, Famotidine, and Ranitidine - can slow the metabolism of the following drugs → increased serum levels:

Cimetidine

Short-term treatment of active duodenal or benign gastric ulcers; treatment of pathological gypersecretory conditions; prophylaxis of stress-ineuced ulcers; treatment of erosive gastroesophageal reflux; relief of symptoms of heartburn and acid indigestion.

Aluminum salts

Calcium salts

Magnesium salts

Sodium bicarbonate

Drug List of Antacids:( inorganic salts)

Magnesium salts

• Effective in buffering acid in the stomach but

have been known to cause diarrhea

• Sometimes used as laxatives

• Can lead to nerve damage and even coma if

absorbed (since these agents are not generally

absorbed systemically)

Calcium salts

• Calcium bicarbonate

• The main drawbacks are constipation and acid

rebound, in which the stomach increases acid

release in response to low acid (high pH).

• Onset of 3-5 minutes

Aluminum salts

• Available as tablets, capsules, suspensions, and liquid, do not cause acid rebound but are not effective in neutralizing stomach acid.

• Bound in feces for excretion

• Related to severe constipation and calcium imbalance

ANTACIDS

• Group of inorganic chemicals that neutralize

stomach acid by direct chemical reaction

• Choice of an antacid depends on adverse

effects and absorption factors.

• Recommended for the symptomatic relief of

upset stomach associated with hyperacidity, as

well as the hyperacidity associated with peptic

ulcer, gastritis, peptic esophagitis, gastric

hyperacidity, and hiatal hernia.

ANTACIDS

Absorption:

Peak levels in 1 to 3 hours

Distribution:

• Widely distributed

• Cross placenta and breast milk

Metabolism:

• Half-life - 2 hours

Excretion:

Urine - can cause electrolyte imbalance in people with renal impairment

ANTACIDS

Contraindication:

• Allergy to ANY of this class

• We need to use with caution for those patients who have electrolyte and acid case imbalance so for those who have renal disease iba ang ibigay na gamot.

ANTACIDS

Use with Caution:

• Any condition that can be Exacerbated by

electrolyte or acid-base imbalance

• Any electrolyte imbalance

• Gl obstruction

• Renal dysfunction

• + Pregnancy and lactation

ANTACIDS

ADVERSE EFFECTS:

• Frequently causes acid rebound, in which the

stomach produces more acid in response to the

alkaline environment

• stimulates gastrin production to cause an

increase in acid production and return the

stomach to its normal acidic state

• increase in symptoms, which results in an

increased intake of the antacid.

• Alkalosis with resultant metabolic changes

(nausea, vomiting, neuromuscular changes,

headache, irritability, muscle twitching, and

even coma) may occur.

SODIUM BICARBONATE

Symptomatic relief of upset stomach from hyperactivity; prophylaxis for GI bleeding and stress ulcers; adjunctive treatment of severe diarrhea; also used for treatment of severe diarrhea; may also be used to treat certain drug intoxication to minimize uric acid crystallization.

ANTACIDS

ADVERSE EFFECTS:

• hypercalcemia and milk-alkali syndrome

• Constipation or diarrhea

• Hypophosphatemia

• Fluid retention and heart failure can occur with

sodium bicarbonate because of its high sodium

content.

dexlansoprazole

esomeprazole

lansoprazole

omeprazole

pantoprazole

rabeprazole

PROTON PUMP INHIBITORS: ( prazole)

PROTON PUMP INHIBITORS

THERAPEUTIC ACTIONS AND INDICATIONS

-Suppress gastric acid secretion

-Inhibiting the hydrogen-potassium

adenosine triphosphatase (H+,

K+-ATPase) enzyme system on the

secretory surface of gastric parietal cells.

PROTON PUMP INHIBITORS

• Blocks the final step of acid production, lowering the acid levels in the stomach

• Short-term treatment of active duodenal ulcers, GERD, erosive esophagitis, and benign active gastric ulcer

• Long-term treatment of pathological hypersecretory conditions.

PROTON PUMP INHIBITORS

• Maintenance therapy for healing of erosive esophagitis and ulcers

Combination with amoxicillin and clarithromycin for the treatment of Helicobacter pylori infection.

PROTON PUMP INHIBITORS

PHARMACOKINETICS (A-D-M-E):

Absorption

• Acid-labile and are rapidly absorbed from the Gl

tract

• Peak levels in 3 to 5 hours

Metabolism

-Liver

Excretion

-Urine

Omeprazole

is faster acting and more quickly excreted than other PPIs

PROTON PUMP INHIBITORS

CONTRAINDICATIONS AND CAUTION:

Contraindication:

-Allergy to ANY of this class

Use with Caution:

• Pregnant or lactating women

• Safety and efficacy not established in patients

<18 y.o. (except lansoprazole) The safety profile

for <18 years old is not yet established.

Therefore, if you are not <18 years old, it is not

recommende

PROTON PUMP INHIBITORS

ADVERSE EFFECTS:

Related to their effects on the H,K - ATPase pump on the parietal and other cells

CNS:

• Dizziness and headache are commonly seen

• Asthenia (loss of strength), vertigo, insomnia,

apathy, and dream abnormalities

GI:

• Diarrhea, abdominal pain, nausea, vomiting, dry mouth, and tongue atrophy

Upper Respiratory Tract:

• Cough, stuffy nose, hoarseness, and epistaxis (nosebleed)

Other:

Rash, alopecia, pruritus (itchiness), dry skin,back pain, and fever

PROTON PUMP INHIBITORS

CLINICALLY IMPORTANT DRUG-DRUG INTERACTION:

• Risk of increased serum levels and increased

toxicity of benzodiazepines (anti-anxiety),

phenytoin, and warfarin if these are combined

with these drugs If the patient is taking

benzodiazepines and he/she needs a PPI, it is a

must to lower the dose of benzodiazepines,

because there is an increase in serum levels.

Baka matulog nalang yang patient mo.

• Decreased levels of ketoconazole and

t h eo ph yl l i ne → l oss o f eff ect i v eness

• Sucralfate - not absorbed well with PPis; spaced

30 minutes apart

• With Clopidogrel - increases risk for CV events

Omeprazole

Short-term treatment of active duodenal ulcer or active benign gastric ulcer; treatment of heartburn or symptoms of gastroesophageal reflux; treatment of pathological hypersecretory syndromes; eradication of H.pulori infection as part of combination therapy.

GASTROINTESTINAL PROTECTANTS

Protects the GI tract, basically it coats the GI Tract

GASTROINTESTINAL PROTECTANTS

ONE DRUG ONLY! Sucralfate

GASTROINTESTINAL PROTECTANTS

THERAPEUTIC ACTIONS AND INDICATIONS

• Forms an ulcer-adherent complex at duodenal

ulcer sites, protecting the sites against acid,

pepsin, and bile salts.

• You drink the medicine, then it will go to the

ulcer part (may depression part), then it will

form a complex, tatakpan yan parang vulcaseal,

para diri na hiya mabuho pa.

• Prevents further breakdown of the area and

promotes ulcer healing.

GASTROINTESTINAL PROTECTANTS

• Kasi paano magheheal it ulcer if it is constantly

exposed to hydrochloric acid.

• Inhibits pepsin activity in gastric juices

• Prevents further breakdown of proteins in the

stomach, including the protein wall of the

stomach

GASTROINTESTINAL PROTECTANTS

CLINICALLY IMPORTANT DRUG-DRUG INTERACTION

• Aluminum Salts - risk of high aluminum levels

and al umi num t oxi ci t y

• With phenytoin, fluoroquinolone antibiotics or

penicillamine - Decreased serum level and drug

effectiveness (Need 2-hour window of the said

medication)

GASTROINTESTINAL PROTECTANTS

PHARMACOKINETICS (A-D-M-E)

Absorption:

Rapidly absorbed after oral administration; because it is a fast-acting medicine

Metabolism:

• Liver

Excretion:

• Feces

• Crosses placenta and may enter breast milk

GASTROINTESTINAL PROTECTANTS

Contraindication:

• Allergy to ANY of its components

• Patients with renal failure or undergoing dialysis

→ build up of aluminum may occur

• Because of sucralfate, nagkakaroon tayo ng

build up of aluminum that would result to further

renal failure

GASTROINTESTINAL PROTECTANTS

Use with Caution:

• Pregnant or lactating women

GASTROINTESTINAL PROTECTANTS

GI:

• Constipation - most frequently/commonly seen AE in the use of GI protectant: Sucralfate

• Diarrhea, nausea, indigestion, gastric discomfort, and dry mouth may also occur.

GASTROINTESTINAL PROTECTANTS

Others:

Dizziness, sleepiness, vertigo, skin rash, and back pain

Sucralfate

Short-term and maintenance treatment of active duodenal ulcer; treatment of oral and esophageal ulcers due to radiation, chemotherapy, or sclerotheraphy.

PROSTAGLANDIN

DRUG LIST

●misoprostol

PROSTAGLANDIN

THERAPEUTIC ACTIONS AND INDICATIONS:

• Misoprostol is pri mari l y used to prevent nonsteroidal anti-inflammatory drug (NSAID)-induced gastric ulcers in patients who are at high risk for complications from a gastric ulcer

PROSTAGLANDIN

PHARMACOKINTEICS (A-D-M-E)

Absorption

-rapidly absorbed from the GI tract

Metabolism

• Liver

• Crosses placenta and may enter breast milk

Excretion

• Urine

PROSTAGLANDIN

Contraindication:

• Allergy

• PREGNANCY - abortifacient

• Patients should be advised to have negative PT

within 2 weeks of beginning treatment

• Begin treatment on the 2nd or 3rd day of their

next menstrual cycle

• Barrier contraceptives

PROSTAGLANDIN

Use with Caution:

• Lactating

• Patients with hepatic and renal impairment

PROSTAGLANDIN

ADVERSE EFFECTS:

GI

• Nausea, diarrhea, abdominal pain, flatulence,

vomiting, dyspepsia and constipation

• GU (Genitourinary)

• Miscarriages, excessive bleeding, spotting,

cramping, hypermenorrhea, dysmenorrhea and

other menstrual disorders

Because prostaglandin not only is for pain but it

plays also a role in coagulation. So too much

may lead to bleeding

Misoprostol

Prevention of NSAID- or aspirin- induced gastric ulcers in patients at risk for complications of gastric ulcers; as an abortifacient with mifepristone.

pancrelipase

saliva substitute

DRUGS USED TO TREAT DIGESTIVE ENZYME DYSFUNCTION:

Salivary Amylase, that digests starches.

What is the enzyme in our saliva?

• Glucose

• Galactose

• Fructose

Give me the 3 monosachharides?

Lactose

Maltose

Disaccharide:

Lactose

(Glucose+ Galactose)

Maltose

(Glucose+Glucose)

Sucrose

(Glucose+Fructose)

DIGESTIVE ENZYMES

THERAPEUTIC ACTION AND INDICATIONS:

• Digestive enzymes are substances produced in

the GI tract to break down food into usable

nutrients

• Some patients— those who have suffered

strokes, salivary gland disorders, or extreme

surgery of the head and neck and those with

cystic fibrosis or pancreatic dysfunction-may

require a supplement to the production of

digestive enzymes.

Saliva

it contains electrolytes and carboxymethylcellulose to act as a thickening agent for dry mouth condition; makes the food

bolus easier to swallow our saliva not only function as the start of the digestive process and the digesting carbohydrates but also in the movement of food bolus down the esophageal

tract)

Pancreatic Enzymes

• we replace this enzymes to help with the digestion and absorption of fats proteins and carbohydrates

DIGESTIVE ENZYMES

PHARMACOKINETICS (A-D-M-E)

• Little is known

• For saliva substitutes - not absorbed

systemically

DIGESTIVE ENZYMES

Contraindication

-Allergy specific to parabens or any component

DIGESTIVE ENZYMES

Use with Caution:

• Patients with heart failure, hypertension or renal

failure kasi dumadami ang sodium.

• Pregnancy and lactation

DIGESTIVE ENZYMES

Contraindications

● Allergy to the product and pork

Use with Caution

● Pregnancy and lactation

DIGESTIVE ENZYMES

ADVERSE EFFECTS:

• Mostly seen with saliva substitute - abnormal electrolyte absorption

• Increased levels of Mg, Na or K; So if we have increased sodium we expect increase water

• For pancreatic enzymes - nausea, abdominal cramps and diarrhea

• Saliva Substitute - allergy to parabens

• Pancreatic Enzymes - allergy to pork

Pancrelipase

Replacement pancreatic enzymes to aid in the digestion and absorption of fats, proteins, and carbohydrates.

• Laxatives

●GI stimulants

●Antidiarrheal agent

DRUGS AFFECTING DRUG MOTILITY:

LAXATIVES

or cathartic, drugs are indicated for the short-term relief of constipation, to prevent straining when it is clinically undesirable (such as after surgery, myocardial infarction [MI], or obstetrical delivery), to evacuate the bowel for diagnostic procedures, to remove ingested poisons from the lower GI tract, and as an

adjunct in anthelmintic therapy when it is desirable to flush helminths from the GI tract.

LAXATIVES

Also named cathartic drugs; Most are available in OTC preparations

Release

Catharcis

LAXATIVES

• Short-term relief of const i pat i on

● To prevent straining when it is clinically

undesirable (such as after surgery, myocardial

infarction [MI], or obstetrical delivery)

● To evacuate the bowel for diagnostic procedures

(e.g. Ultrasound, colonoscopy)

LAXATIVES

• To remove ingested poisons from the lower Gl

tract; can be used in treatment for toxicology

but not all

● Adjunct in anthelmintic therapy when it is

desirable to flush helminths from the GI tract;

e.g. of helminths: ascaris

○ If the helminths dies they will not go out

once this happens it will occlude the GI tract, pwede na sila gamitan ng laxatives.

LAXATIVES -CHEMICAL STIMULANTS

• directly stimulate the nerve plexus in the intestinal wall, causing increased movement and the stimulation of local reflexes.

bisacodyl

cascara

castor oil

senna

LAXATIVES (DRUG LIST):

LAXATIVES

THERAPEUTIC ACTIONS AND INDICATIONS

• Directly stimulate the nerve plexus in the

intestinal wall → increased movement and the

stimulation of local reflexes. ; Take note local

reflexes kanina, gastrocoli, gastroenteri, kasi

pagumiinom ka may kinakain ka rin diba, hindi

lang directly nastistimulate ang nerve plexus,

pati rin nastimulate mo ang gastrocoli

• All of these agents begin working at the

beginning of the small intestine and increase

motility throughout the rest of the Gl tract by

irritating the nerve plexus.; minimally absorbed;

Onset of Action: Castor Oil - 2-6 hours

LAXATIVES

Contraindications:

• Allergy to ANY of this class

• Acute abdominal disorders (appendicitis,

diverticulitis, and ulcerative colitis); Because

they function by irritating the nerve plexus,

because these disorders are inflamed and

irritated

• Pregnancy (Castor Oil) - associated with

premature labor)

LAXATIVES

Use with Caution

●Heart block and patients with CAD or

debilitation

• Pregnancy and lactation

LAXATIVES

ADVERSE EFFECTS

● Cathartic dependence (in frequent laxative

use); causes constipation when the patient uses

it frequently, without the laxative

• Gl effects of diarrhea, abdominal cramping,

and nausea, sweating, palpitation =

Parasympathetic Stress Reaction

CNS (related to fluid and electrolyte imbalances)

○ including dizziness, headache, and

○ Weakness

• Sweating, palpitations, flushing, and even

fainting - sympathetic stress reaction

• Castor oil blocks absorption of fats (including

fat-soluble vitamins) and may lead to

constipation from GI tract exhaustion

• Specifically related to chemical stimulants,

cascara, though a reliable agent, may have a

slow, steady effect or may cause severe

cramping and rapid evacuation of the contents

of the large intestine. Castor oil blocks

absorption of fats (including fat-soluble

vitamins) and may lead to constipation from GI

tract exhaustion when there is no stimulus to

movement.

LAXATIVES

CLINICALLY IMPORTANT DRUG-DRUG INTERACTION:

• Because laxatives increase the motility of the GI

tract and some interfere with the timing or

process of absorption, it is advisable to not take

laxatives with other prescribed medications.

• Administration of laxatives and other

medications should be separated by at least 30

minutes

Castor oil

To evacuate the bowel for diagnostic procedures; to remove ingested poisons from the lower GI tract; an adjunct in athelmintic therapy when it is desirable to fluch helminths from the GI tract.

LAXATIVES - BULK STIMULANTS METHYLCELLULOSE

• (also called mechanical stimulants)

• are laxatives that cause the fecal matter to

increase in bulk. They increase the motility of the

GI tract by increasing the size of fecal matter,

which helps to pull more fluid in the intestinal

contents. This will stimulate local stretch

receptors and activate local activity.

LAXATIVES - BULK STIMULANTS METHYLCELLULOSE

THERAPEUTIC ACTIONS AN INDICATIONS:

• Also called mechanical stimulants

• Cause the fecal matter to increase in bulk

• Increases the size of fecal matter, which helps to

pull more fluid in the intestinal contents →

stimulate local stretch receptors like duodenum colic reflex kaya nagkakaroon ng motion, and activate local activity

methylcellulose

polycarbophil

psyllium

LAXATIVES - BULK STIMULANTS METHYLCELLULOSE (DRUG LIST):

Methylcellulose

is a wheat starch bulk-forming fiber that can increase the size of fecal material in the GI tract.

Polycarbophil

is a natural substance that forms a gelatin-likebulk out of the intestinal contents. This agent stimulates local activity. It is considered milder and less irritating than many other bulk

stimulants.

Psyllium

another gelatin-like bulk stimulant, is similar to polycarbophil in action and effect.

LAXATIVES - BULK STIMULANTS METHYLCELLULOSE

Absorption:

• These drugs are all taken orally.

• Generally not absorbed systemically - only

exerts therapeutic effects directly in the GI tract

• They can be rapidly acting, causing effects as

they pass through the GI tract. However, some

people may not have relief of constipation for a

few days with these agents.

• Bakit if kumain ng maraming utan damo it bulk?

Because in biochemistry basing on the direction

of carbon atoms the alpha and beta, fortunately

and unfortunately, humans only have alpha

enzymes so beta structures including cellulose

hindi kaya nating idigest, so they functiona s

fiber material.

LAXATIVES - BULK STIMULANTS METHYLCELLULOSE

Contraindications:

• Allergy to ANY of this class

• Acute abdominal disorders (appendicitis,

diverticulitis, and ulcerative colitis); Because

again we stimulate motion on the Gi tract, if

there is anything wrong, we don't want it, this

one comparing to stimulants; we should not give

to those patients who have intestinal

obstructions

• Intestinal obstruction, perforation or healing

from acute abdominal surgery

LAXATIVES - BULK STIMULANTS METHYLCELLULOSE

Use with Caution

• Heart block and patients with CAD or

debilitation

• Pregnancy and lactation