Antidiarrheals: Nursing pharmacology

Antidiarrheals are a group of medications that are used to treat diarrhea, which is characterized by loose, watery stool, or an increased frequency of bowel movement.

Now, based on their mechanism of action, antidiarrheals can be broadly divided into four main groups: opiates and opiate-related agents, somatostatin analogues, adsorbents, and bulk-forming agents.Let’s start with opioids like loperamide, diphenoxylate, difenoxin, and paregoric.

These are taken orally and work by stimulating the opioid receptors found in the intestinal wall, which decreases peristalsis or bowel movement.

The slowed transient time allows for increased absorption of fluid and electrolytes into the fecal mass.Next, there are somatostatin analogues, such as octreotide.

This can be administered orally, subcutaneously, intramuscularly, or intravenously, and it’s mostly used to treat diarrhea associated with certain tumors or chemotherapy.

The way octreotide works is by binding to somatostatin receptors and mimicking somatostatin’s effects. These include inhibiting hormone release by the pancreas and gastrointestinal tract, as well as slowing down peristalsis and decreasing the secretion of fluid and electrolytes into the bowel lumen.Moving on to adsorbents, these include bismuth subsalicylate, and are taken orally.

Once in the intestinal lumen, bismuth subsalicylate has protective properties, since it can coat the walls of the intestines, as well as antimicrobial properties, since it can kill causative bacteria.

In addition, bismuth subsalicylate has antisecretory actions, so it helps reduce how much fluid is secreted into the bowel lumen.Finally, bulk-forming agents include methylcellulose, polycarbophil, and psyllium.

Now, these medications can’t be digested, so they remain in the intestinal lumen and end up getting incorporated into the stool.

As a result, bulk-forming agents work by absorbing water, making the stool swell up into a bulky mass. In addition, bulk-forming agents can be used as laxatives.

Now, the most common side effect of antidiarrheals is constipation. In addition, opioid agents can also cause central nervous system and respiratory depression if combined with other CNS depressants, like benzodiazepines, barbiturates, and alcohol.Now, loperamide has a boxed warning regarding torsades de pointes and sudden death with high doses.

On the other hand, octreotide can impair gallbladder function, which may lead to cholelithiasis. Finally, bismuth subsalicylate may temporarily stain the tongue and stools black.

As far as contraindications go, these are mostly for the opioids. So, they should not be given to clients with severe hepatic or renal impairment, since they can induce hepatic coma.

Now, loperamide should not be used in clients younger than 2 years old or those with risk factors for QT prolongation. On the other hand, diphenoxylate and difenoxin should be used with caution in children younger than 4 and in older adults, since these clients are at an increased risk for CNS and respiratory depression.

In addition, diphenoxylate and difenoxin are typically given in the form of preparations that contain atropine, so these should be avoided by clients with narrow angle glaucoma, since atropine can worsen the obstruction of aqueous humor drainage.Antidiarrheals that slow peristalsis, like opioids and octreotide, should not be used when diarrhea is caused by bacteria like Clostriodiodes, and toxigenic Salmonella, Shigella, or E.

coli. Finally, bismuth subsalicylate is contraindicated for children who are recovering from a viral infection, and should be used with caution in adult clients taking aspirin.Alright, before administering an antidiarrheal medication, ask your client about any recent travel, antibiotic use, or hospitalization, or if they have recently consumed foods like undercooked meat or unpasteurized dairy products.

Be sure to obtain a baseline of your client’s symptoms, such stool characteristics and frequency. Check your client’s vital signs and assess for signs of dehydration, such as decreased urine output, dark yellow urine, or decreased skin turgor.

Then, perform an abdominal assessment to check for any localized tenderness, distention, altered bowel sounds, rebounding, or guarding.

Lastly, note laboratory test results, specifically CBC, electrolytes, stool culture. Now, if your client is prescribed an antidiarrheal medication, explain why the medication is prescribed, and instruct them to take their medication with plenty of water and other fluids, such as broth or soup, to help prevent dehydration.

Also let them know about some of the common side effects they may experience, such as constipation and gastrointestinal discomfort.

If your client is prescribed an opioid like loperamide, instruct them to avoid taking tranquilizers, sedatives, or alcohol, and advise them to avoid hazardous activities like driving if they experience dizziness or drowsiness.

Also teach your client to take only the prescribed amount of the medication, because higher doses can cause abnormal heart rhythms.

When bismuth subsalicylate is prescribed, let them know that it may cause their stools to turn black, and their tongue may become dark; and reassure them these should resolve after treatment.

Also caution against using other salicylates, like aspirin, when taking bismuth subsalicylate. If your client is prescribed octreotide, teach them to take their medication on an empty stomach, or at least one hour before or two hours after meals.

Advise them to inform their healthcare provider if experiencing right upper quadrant pain, if they develop fever, chills, or if they notice clay-colored stools.

And finally, stress the importance of contacting their healthcare provider if their diarrhea continues for more than 48 hours, or if they develop signs of dehydration, such as sluggishness, lightheadedness, or if their urine becomes very dark.Alright, as a quick recap, antidiarrheals are medications used to treat diarrhea, and common side effects include constipation and gastrointestinal discomfort.

Opioid agents can also cause dizziness and drowsiness, so clients should avoid hazardous activities if they experience these symptoms; loperamide can cause torsades de pointes and sudden death with high doses; bismuth subsalicylate may darken the tongue and cause black stools; and finally, octreotide can impair gallbladder function.

Instruct your client to contact the healthcare provider if diarrhea lasts longer than 48 hours, or if they develop signs