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Treatment of Helicobacter Pylori

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Bismuth subsalicylate (Pepto Bismol) + Metronidazole+Tetracycline/Amoxicilin/Clarithromycin (Biaxin)

Indication: Helicobacter pylori causes ulcers and gastritis by burying itself between mucus and epithelial layers of gastric mucosa and then shielding itself with a urease barrier (converts urea to ammonia). Ammonia destroys protective mucous barrier.

MOA: killing H. Pylori promotes healing & prevents relapse.

Contra/Side Effects: Bismuth Subsalicylate: smelly black stool.
Metronidazole: blocks aldehyde dehydrogenase (bad if drinking alcohol)
Tetracycline/Amoxicillin/Clarithromycin: nausea & vomiting.
▪ Take triple combo for 14 days to eradicate bacteria. Otherwise, you are likely to get ulcers again.

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Proton Pump Inhibitors

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Omeprazole (Prilosec)
Esomeprazole (Nexium)
Lansoprazole (Prevacid)

PROTON PUMP INHIBITORS

Indication: Peptic Ulcer Disease.


▪The most potent drugs as they directly target the pump that moves H+ into the stomach

▪MOA:
PPIs enter the parietal cell and breaks down H+ into sulfa-related intermediates that bind to the proton pump & block acid release.
By decreasing the acidity of the stomach, H. pylori’s ammonia barrier becomes toxic to itself & it dies. This accounts for the slight antibacterial effect of PPIs.
▪Effective enough to shut down 90% of acid release for 24 hrs.

Note:
▪Omeprazole inhibits P450s, but to a lesser extent than Cimetidine. C
Comes in S & R (racemic) form. S is the active form.
▪Esomeprazole is the S form of Omeprazole.

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Prokinetic Drugs

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Metoclopramide
Bethanechol (muscarinic cholinergic agonist)

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Drugs that can be used for mucosal protection in ulcers:

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Sucralfate
Bismuth subsalicylate
Prostaglandins

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Antacids

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▪Sodium Bicarbonate
▪Calcium Carbonate
▪Magnesium Hydroxide
▪Aluminum Hydroxide
▪50/50 COmbinations of Mg & Aluminum salt (to balance side effects)

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Sodium Bicarbonate

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Antacid

Indication: Peptic Ulcer Disease

MOA: NaHCO3 + HCL -> NaCL + H2O + CO2 (the problem).

CO2 causes stomach distention that will add pressure to teh stomach.
A lot of bicarbonate absorption can cause metabolic alkalosis.

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Calcium Carbonate

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Antacid (TUMS)

CaCO3 + 2HCl -> CaCL2 + H2O + CO2.
Produces CO2, but not as much as sodium bicarbonate.
Was also marketed for osteoporosis in women.

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Magnesium Hydroxide

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Antacid (Milk of Magnesia)
Indication: Peptic Ulcer Disease
MOA: combines with HCL to give Magnesium Chloride and water.
▪No CO2 is made here.

Side Effects: lots of diarrhea

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Aluminum Hydroxide

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Antacid (Rolaids)

Indication: Peptic Ulcer disease

MOA: Combines with HCl to produce Aluminum Chloride and water.

Side effect: Lots of constipation.

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50/50 Combos of Antacid Drugs

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Maylox, Mylanta
50/50 combinations of Aluminum hydroxide & manesium hydroxide = ANTACIDS

Indication: Peptic Ulcer Disease

MOA: Mg causes diarrhea and Aluminum causes constipation. At the end of the lower GI tract, tehse drugs cancel each other out for a minimal effect on your bowels.

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Sucralfate

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Cytoprotectant

Indication: Peptic Ulcer Disease

MOA: At the site of an ulcer, these is no mucous in the stomach. Psotiively charged proteins are exposed. The negatively charged sulfates in sucralfate chemically bind the positively charged nitrogens of exposed proteins. This forms a cytoprotectant & allows the epithelium to start regenerating from teh bottom up. It also acts as a barrier from further attack by acid & pepsin.

Side effect: Constipation

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Misoprostol

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Cytoprotective
Prostaglandin Derivative

Indication: Peptic ulcer disease. Particularly for patients on NSAIDs or other drugs that inhibit Cox-1 [an enzyme that is responsible for production of gastric mucosa.] Can act as a replacement therapy for patients on Cox inhibitors, to promote mucous production.

MOA: Activates inhibitory G regulatory proteins on the parietal cell to (1) decrease HCl secretion and also act on a cascade to (2) produce mucous.

Side Effects: Lots of Diarrhea, Abortifacient (produces spontaneous abortions).
Contraindicated in women of child bearing age.

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Combination Therapies to Treat Peptic Ulcer Disease

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▪ Clarithromycin + omeprazole + metronidazole

▪Bismuth Subsalicylate + Metronidazole + Tetracycline + Ranitidine

▪Ranitidine Bismuth Citrate (tritec) + Clarithromycin

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Drugs used to treat GERD

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▪Antacids
▪H2 blockers
▪Antacids + H2 blockers
▪Proton Pump Inhibitors
▪Metoclopramide (Reglan)
Dopamine blocker, 5HT3 blocker, Muscarinic Agonist

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Four Goals for Treatment of GERD

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1) DECREASE THE REFLUX. Done by decreasing gastic volume. Eat small meals & don't eat at bedtime. (Also, avoid smoking, chocolate, alcohol, caffeine; eat bland diet)

2) NEUTRALIZE TEH REFLUX. Use antacids for instantaneous relief. For long term, use PPI/H2 blockers.
Drug: Pepcid complete contains both antacid + Famotidine.

3)ENHANCE CLEARANCE. Chew um, tilt head up with pillows at hight so that gravity helps.
Drug: Metoclopramide (prokinetic) is a cholinergic & dopaminergic agonist that can directly increase gastric emptying.

4) PROTECT ESOPHAGEAL MUCOSA.

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Beano

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Antiflatulence

Indication: to decrease farting

MOA: contains alpha-galactosidase which breaks down carbs. It starts digesting food before it hits your mouth.

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Simethicone

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Antiflatulence

Indication: To decrease farting

MOA: Defoaming agent that combines gas bubbles into one large explosive bubble.

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Emetic Agents

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SYRUP OF IPECAC
MOA: works on CTZ (chemo-receptor trigger zone at the postrema)
Warning: Toxic ingestion, not recommended anymore.
Abused by bulimics.


APOMORPHINE (Dopamine Agonist.)
Indication: To induce emesis (especially in the ER to treat drug overdoses)
▪Only available by Injection
▪A conjugate of morphine that lacks the analgesic (pain-killing) effects.

MOA: Acts on CTZ to stimulate D2 (dopamine 2) receptors & cause emesis.

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Anti-Emetics

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▪Phenothiazines (e.g. chlorpromazine)

▪Ondansetron

▪Metoclopramide

▪Cannabinoids (e.g. THC/nabilone)

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Phenothiazines (e.g. Chlorpromazine)

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DA ANTAGONIST

Indication: Anti-emetic. Administered IV at hospital. For suppository use at home.
to treat Psychiatric disorders.

MOA: Block dopamine receptors (D2)

Side Effects: Extra-pyramidal effects (Parkinson's Symptoms).

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Ondansetron

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5HT3 antagonists

Indication: Anti-Emetic
Especially useful as a remedy against SEVERE cancer treatment induced nausea


MOA: Blocks Serotonin receptors at CTZ

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Metoclopramide

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DA blocker, 5HT3 blocker, Muscarinic agonist.

Indication: GERD

MOA: Increases Muscarinic activity (to increase motility of GI tract (prokinetic) which is useful in treatment of GERD.
DA and 5HT3 block reduces nausea at the CTZ of the area postrema.

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Tetrahydrocannabinol (THC)

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Trade name: Nabilone

Indication: Anti-emetic (especially for severe cancer treatment induced nausea)

MOA: Unknown, but involves cannabinoid receptors in brain.

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Drugs that Treat Motion Sickness

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ANTICHOLINERGICS:
Scopolamine (Muscarinic antagonist: cousin of atropine)
▪Worn as transdermal patch behind ear.
▪Takes 4-5 hrs to reach bloodstream. Lasts for 3 days if worn continuously.
Side Effect: anticholinergic side effects (mydriasis & dry mouth).


ANTIHISTAMINE (H1 blockers)
Dimenhydrinate (Dramamine)
Diphenhydramine
Meclizine
Cyclizine
▪Not useful n treating nausea associated with anti cancer agents (use THC & Ondansetron).
▪useful in conjunction with allergic reactions.
Side effects of H1 blockers: Sedation.

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Antidiarrheals

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▪Be careful of electrolyte balances. Note potassium in children. If left untreated, children will become dehydrated & may develop CV problems (potentially leading to death).

▪ORAL REHYDRATION & ELECTROLYTE REPLACEMENT: liquid solutions containing glucose, salts, etc. designed to replace fluids & electrolytes.
E.g. Gatorade & Pedialyte

▪NARCOTICS:
LOMOTIL - diphenoxylate & atropine
IMODIUM - Loperamide.
MOA: decrease peristalsis by decreasing contraction of the longitudinal muscles of the GI tract & increasing contraction of the circular muscles. This action slows transit time, allowing more time for water & electrolyte absorption.

▪PEPTO-BISMOL (bismuth subsalicylate)
Ued on a prophylactiv basis for people about to travel. Has a slight anti-bacterial & anti-inflammatory activity.
MOA: for diarrhea, MOA is unknown.

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LAXATIVES

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BULKS (1-3 days onset)
▪Psyllium seeds - metamucil.
▪MOA: bulks for a gelatinous mass that increases in size, causing pressure in the intestines that stimulates normal peristalsis.

IRRITANTS/SEMI-FLUIDS/EVACUANTS (6-8 hr onset)
▪Anthraquinones - senna, cascara sarada
▪Castor oil - ricinoleic acid
▪Diphenylmethanes - bisacodyl (Ducolax, Ex-Lax)
MOA: promotes secreteion of electrolytes and water back into the lumen of the GI tract.

WATERY EVACUATIONS (1-3 hours onset)
▪Salienes (Mg Citrate)
▪Milk of Magnesia
▪GoLYTELY (used before colonoscopy)
MOA: Hyperosmotic solutions brin water into teh GI tract

OTHER AGENTS
▪Mineral Oil
▪Sufactants - dioctyl Na sulfosuccinate (Colace)
▪Suppositories (Glycerin, Pharmala)