Tutorial 7,8,9,10 Questions (Module 4) Flashcards
(19 cards)
You look up Benjamin’s dispensing history and see that he was prescribed Motilium® (domperidone) 10 mg three times a day when required about two years ago. You are aware that domperidone is available on prescription only. Sally points to the Anagraine® (metoclopramide 5 mg and paracetamol 500 mg) and Nausetil® (prochlorperazine 5 mg) on the shelf, and asks you how are these antiemetics (medication for nausea and vomiting) different to the Motilium® that Benjamin had taken in the past.
Compare and contrast pharmacological actions of domperidone, metoclopramide and prochlorperazine:
They are all D2 receptor antagonists in the chemoreceptor trigger zone in the central nervous system. Act as 5-HT4 receptor agonist in the enteric nervous system to increase gastric motility and therefore gastric emptying. Metoclopramide and prochlorperazine cross the BBB which causes central nervous system adverse effects. Domperidone doesn’t cross the BBB and therefore be used in Parkinson’s.
Domperidone and metoclopramide are prokinetic. Has peripheral actions on the GIT, increase motility of oesophagus, stomach, intestine. Accelerate gastric emptying without stimulating H+ release, increase lower oesophageal sphincter tone and improve efficacy as an antiemetic.
Before they leave the pharmacy, Sally mentions their upcoming short stay at Rottnest next week. She is hoping Benjamin is well by then so they can enjoy a weekend away. They are taking their 16-year-old grandson who often vomits on ferries. He has no medical conditions and takes no medications. You have Avil® (pheniramine) and Travacalm Original® (dimenhydrinate, hyoscine hydrobromide, caffeine), both of which are indicated for travel sickness in your pharmacy. Compare and contrast the mechanisms of actions of these drugs
Pheniramine is an anti-histamine, binds to H1 receptors and inactivates them. Results in reduced smooth muscle contraction and vasodilation. Crosses the blood-brain barrier binding to CNS H1 receptors.
Travacalm original
Dimenhydrinate: antihistamine works the same way as an antihistamine. But, it also has anti-emetic effects.
Hyoscine hydrobromide: anticholinergic agent, acting centrally and in the periphery to block actions of acetylcholine. The effects on the gastrointestinal system include reducing motility and secretions.
Caffeine: Added to counter the drowsiness in the other active ingredients.
Both medications cause drowsiness, both in an oral dosage form. Recommend travacalm.
Andrea returns three days later. She has found the Buscopan® (hyoscine butylbromide) very effective for the cramps and has not needed it today and is generally feeling much better. The only thing that is bothering her now is the slight abdominal discomfort when she has gas, which is often. She feels so relieved when she gets rid of the gas however is finding it is not always easy to expel the gas. She is hoping you can recommend something for her gas and the bloating she is experiencing with it. Her friend at work recommended Mintec® (peppermint oil 0.2 mL) and DeGas® (simethicone). The friend also mentioned piercing the Mintec® capsules to make them work quicker. What about be your advice? Compare and contrast pharmacological actions of peppermint oil and simethicone and any precautions/contraindications and adverse effects.
Peppermint oil: Is an antispasmodic, reduces muscle spams. It also reduces bloating. Must be swallowed whole, if capsules were pierced, it would cause irritation in the lining of the gastrointestinal tract. Adverse effects: rash, heartburn, perianal itching/burning
Simethicone: Anti-foaming agent that lowers the surface tension of gas bubbles allowing for easier expulsion. Adverse effects: may cause nausea/diarrhea
Use simethicone (safe in pregnancy)
Andrea’s dietician has recommended her to take a fiber supplement. She points to the Metamucil® supplement on the shelf and asks for your advice. Provide information to Andrea on this fiber supplement and directions for use.
Bulk-forming laxative – drawing water into the colon to increase the bulk of stool to promote peristalsis whilst improving the consistency of stool.
Dosage and directions: 2 spoons in water 1-3 times daily. Takes 2-3 days to have an effect. Increase fluid intake during this time.
Camille returns to the pharmacy about a week later as the Mylanta® has been helping with discomfort immediately following meals, however, she tells you that overnight and at other points in the day it really isn’t enough. Her husband has purchased Somac Heartburn Relief® (pantoprazole) tablets and Zantac Relief® (ranitidine) tablets over the counter in the past for his heartburn and she wants to know can she use these products. Compare and contrast the mechanisms of actions of each of these products and provide a recommendation as to whether either option would be appropriate for your patient, considering she is 30 weeks pregnant.
Pantoprazole is a proton pump inhibitor, works by irreversibly blocking the hydrogen and potassium ATPase enzyme or the gastric proton pump which is found within the parietal cells of the stomach and is the final step of acid production. Results in less acid in the stomach. Not suitable for use in pregnancy.
Ranitidine is an H2 antagonist, competes with histamine for H2 receptors on the stomachs parietal cells and stops the production of hydrochloric acid, pepsin secretion is also reduced. It is a reversible process.
Recommend using ranitidine as pantoprazole is not safe to use in pregnancy.
Camille asks you if she can try an alternative option to Mylanta® liquid as she has grown to dislike the taste so much it is making her queasy to think about drinking it; she thinks due to being pregnant she tends to quickly grow aversions to certain flavours. She has a few names on her mobile phone from doing a bit of research, of which you have three in your pharmacy: Gaviscon Double Strength® liquid (sodium alginate, potassium bicarbonate, calcium carbonate), Andrews Tums® chewable tablets (calcium carbonate) and Rennie® chewable tablets (calcium carbonate, magnesium carbonate), which are all indicated for the treatment of dyspepsia and are safe in pregnancy. Compare and contrast their mechanisms of actions and adverse effects. Describe the interactions with her current/prescribed medications.
They are all antacids with the exception of Gaviscon double strength liquid which is an antacid combined with alginate.
Mechanism of action of antacid: Combination of aluminum, calcium and magnesium salts to neutralize hydrochloric acid secreted by parietal cells in the stomach. It makes stomach contents less acidic. Inhibits pepsin also.
Mechanism of action of antacid with alginate: Alginate is derived from seaweed, form protective layer on top of gastric content to create a protective barrier to prevent reflux
Adverse effects of antacids: may cause constipation, diarrhea, and nausea.
> Al and Ca: constipation
>Mg: diarrhea
Interaction with other medications: Space other medications 2 hours apart when taking antacids as it decreases absorption of other medications.
As advised, Kenneth sees his GP immediately who arranges an endoscopy. Upon assessment, Kenneth’s GP confirms the diagnosis of NSAID-induced peptic ulcer disease. How do you think Kenneth’s case could be managed?
- Minimize NSAID use
- If NSAID required –> use least toxic, lowest possible dose, shortest acting, use for as short a time as possible. Use PPI alongside NSAID (does not prevent ulcer recurrence but reduces risk)
- use standard dose PPI for 8-12 weeks and double dose H2 antagonists.
- Test and treat for H pylori after the ulcer has healed
- Do an endoscopy
Describe the pharmacological actions of the NSAIDs Kenneth is using and explain how NSAIDs can induce ulcers.
NSAIDs work by inhibiting COX-1 and COX-2. It is more selective for COX-1 (weakly). Reduces prostaglandin synthesis by inhibiting COX-2 which results in vasodilation and reduced inflammation. Has analgesic effects due to less sensitization of nociceptive nerve endings.
Protective prostaglandins that protect the stomach lining from stomach acid are produced by an enzyme called COX-1. By blocking the COX-1 enzyme and disrupting the production of prostaglandins in the stomach, NSAIDs cause direct irritation of the gastric mucosa which leads to ulcers and bleeding.
Two months later, Kenneth’s ulcers have healed and the GP would like to screen him for H. pylori infection. What tests are available to confirm the diagnosis of H. pylori infection?
Serology blood test
- Presence of H. pylori specific IgG antibodies
Urea breath test
- Urease is not present in human cells, detection means that urease producing organism (h.pylori) is present
- The patient swallows a 13carbon-urea capsule
- The capsule comes in contact with gastric mucosa
- If urease is present, it splits the urea into CO2 and NH3 (ammonia). C02 is absorbed into the stomach lining & exhaled in the breath as labeled carbon 14 dioxide
- Breath samples are analyzed using a liquid scintillation counter for radioactivity
Stool antigen test
- Presence of H. pylori antigen in the stool
Stop PPI 2 weeks before test and antibacterial 4 weeks before the test.
If the tests indicate positive results for a H. pylori infection, what would be the aim of treatment and the first line treatment option? If Kenneth is allergic to penicillin, what regimen would be recommended?
Aim: speed up healing and reduce the chance of recurrent ulcer
First-line treatment (one PPI and two antibiotics):
Esomeprazole/omeprazole 20mg bd, metronidazole 400mg bd (amoxicillin if wasn’t allergic to penicillin), clarithromycin 500mg bd.
Take for 7 days
Ali tells you that he remembers seeing his elderly father using Movicol® (macrogol 3350 with electrolytes) powder for oral solution and Metamucil® (psyllium). Compare and contrast the pharmacological actions of these products containing macrogol 3350 (with electrolytes), docusate sodium with sennosides and psyllium:
Macrogol 3350 with electrolytes: osmotic laxative that draws water into the colon, softens the stool and stimulates peristalsis.
Docusate sodium with sennosides: Docusate is a stool softener that draws water into the stool making it softer, senna is a stimulant that increases gastrointestinal motility by stimulating colonic nerve ending.
Psyllium: Bulk-forming laxative that draws water into the colon to increase the bulk of the stool, causes distension of colon and stimulates peristaltic activity. Improves the consistency of the stool.
Ali has not passed a stool in 3 days and is very uncomfortable. He is purchasing a new Movicol® powder for oral solution, however, he doesn’t think he can wait until tomorrow for it to have an effect. Is there anything he can use for immediate relief? He is now willing to consider a suppository as long as he achieves a quick result. You have the following products in the pharmacy: Glycerol® (glycerol) Suppositories (adult) and Dulcolax® (bisacodyl) suppositories, which are all indicated for the treatment of constipation. Compare and contrast their mechanisms of actions and adverse effects.
Glycerol suppositories are osmotic laxatives, draws water into the colon, softens the stool which lubricates and facilitates the expulsion of the stool. Useful for quick relief of symptoms (30mins)
Bisacodyl suppositories are stimulant laxatives, increases gastrointestinal motility by stimulating the colonic nerve ending.
Adverse effects: rectal discomfort and hypersensitivity reactions
While in the pharmacy, Maria receives a call from work advising her to travel to Sydney tomorrow for an urgent meeting. Would this information change your advice? Is there anything else in the pharmacy that you could recommend? You have Imodium® (loperamide) and Lomotil® (atropine sulfate and diphenoxylate hydrochloride) in your pharmacy. Compare and contrast pharmacological actions of loperamide and diphenoxylate hydrochloride with atropine sulphate, and provide your recommendation.
They both activate mu-opioid receptors in the myenteric plexus gut wall. Decrease bowel motility and increased fluid absorption. Both oral tablets for diarrhea.
Loperamide: doesn’t cross BBB and exhibits anti-secretory properties
Diphenoxylate and atropine: crosses BBB, therefore has adverse CNS effects including drowsiness, dizziness, dry mouth. Atropine is added to avoid misuse of the drug (anticholinergic properties at high doses)
Recommendation: Use loperamide as it doesn’t have CNS adverse effects such as drowsiness and dizziness when she travels.
Some medications can cause diarrhoea, whilst some can cause constipation, hence patient assessment is essential to identify any potential causes of these common GI conditions. Provide two examples of medications that can cause diarrhoea and two that can cause constipation.
Medications that cause constipation: Anticholinergics (antihistamines) and opioids (codeine, pholcodine), antacids (aluminum and calcium)
Medications that cause diarrhea: NSAIDs, PPIs, antacids (magnesium)
About a month later, Cadence is back in the pharmacy with symptoms of anal fissure. Cadence has seen the GP who has confirmed the diagnosis. Cadence wants to know the difference between Rectinol® ointment (zinc oxide, cinchocaine hydrochloride) and Rectogesic® ointment (glyceryl trinitrate). Compare and contrast the pharmacological actions of each of these preparations and provide a recommendation as to which preparation, if any, if appropriate for Cadence given her diagnosis of anal fissure.
Rectinol® ointment (zinc oxide, cinchocaine hydrochloride): Zinc oxide is an astringent which forms a physical barrier by a layer of surface proteins, relieves pain and inflammation. Cinchocaine hydrochloride is a local anesthetic, block voltage-gated sodium channels result in no entry of sodium ions in the cell which means no depolarisation. Therefore no action potential is generated
Rectogesic ointment (glyceryl trinitrate): It is a vasodilator that relaxes the sphincter, reduces anal pressure and promotes improved blood flow.
Use rectogesic ointment, it is more appropriate for anal fissures. Will reduce her symptoms faster and bring faster pain relief. Will relax the anal sphincter and reduce anal pressure.
Cadence asks you for your advice about non-pharmacological management for constipation for her 9-year-old son, Jason. Cadence read about the importance of maintaining good toileting posture and the benefit of using a toilet stool, but she is unsure what it involves. What would you advise?
35 degree angle created by a toilet stool can help open the rectum and pass stool easier. 4 steps to use it:
- make sure your knees are higher than your hips
- lean forward and put your elbows on your knees
- bulge out your abdomen and straighten your spine
- don’t tighten the stomach, take a deep breath and relax anal sphincter to let stool out
Mona is very thankful for your advice, but she is also interested to find out more about how threadworms are transmitted. Describe the lifecycle of threadworm to Mona in a patient-friendly language.
- Infection begins when pinworm eggs are ingested usually directly through contaminated hands or indirectly through contaminated food, bedding, clothing or other articles
- Eggs travel to the gut where they hatch and mature
- Four weeks after ingestion, adult female threadworm moves down the gut and exits the body via the anus to lay a batch of eggs, usually in the night. The worm then dies.
- Eggs may cause intense itching, especially at night, children can reinfect themselves by scratching anus and scraping eggs under their fingernails. Eggs transferred to the mouth and the whole lifecycle starts again
- Eggs can survive for several days in the right conditions.
You notice two different products in your pharmacy: Combantrin 1® (contains: mebendazole) and Combantrin® (contains: pyrantel). Compare and contrast the mechanisms of actions of pyrantel and mebendazole.
They are both anthelmintic treatment options.
Mebendazole: Broad-spectrum anthelmintic, inhibits polymerization of helminth B-tubulin, interfering with glucose uptake. Causes immobilization and death of adult worms.
Pyrantel: Broad-spectrum depolarizing neuromuscular blocker. Induces persistent activation of nicotinic acetylcholine receptors. It causes spastic paralysis of the worm and expulsion from the gastrointestinal system. Poorly absorbed from the gastrointestinal system.
Are these medicines (e.g. mebendazole, pyrantel) safe to be taken by pregnant or breastfeeding women?
Mebendazole: Cat B3 (avoid during 1st trisemester). Safe in breastfeeding
Pyrantel: Cat B2 (safe in 1st-trimester pregnancy, need to confirm the diagnosis to be used). Safe in breastfeeding
