H2 blockers may not receive as much attention as proton pump inhibitors, but they continue to play an important role in managing acid-related disorders. In this episode of the Real Life Pharmacology podcast, we’ll review how H2 blockers work, compare the available agents, discuss important adverse effects, renal dose adjustments, drug interactions, and identify the patients who are most likely to benefit from these medications. Whether you’re a pharmacist, nurse, pharmacy technician, physician, or student, this episode provides practical clinical pearls you can apply immediately to patient care.
In this episode, I also discuss a new podcast I discovered – go check out the Mechanism of Action Podcast! It is an entertaining and educational look at how many of the medications used today were discovered and derived.
Proton pump inhibitors (PPIs) are among the most commonly prescribed medications, but understanding how they work is essential for using them safely and effectively. In this episode of the Real Life Pharmacology podcast, we’ll break down the pharmacology of PPIs, including their mechanism of action, common brand and generic names, clinical uses, adverse effects, drug interactions, and important monitoring considerations. Whether you’re a pharmacist, nurse, pharmacy technician, or student, this episode will help reinforce the key concepts you need to confidently apply PPI pharmacology in clinical practice.
Bisacodyl, commonly known by the brand name Dulcolax, is a stimulant laxative widely used for short-term relief of constipation and bowel preparation before procedures. It works by directly stimulating the enteric nerves in the colon, increasing peristalsis, and promoting bowel evacuation.
Mechanism of Action: Bisacodyl acts primarily on the large intestine. It stimulates intestinal smooth muscle and alters water and electrolyte transport, increasing fluid accumulation in the bowel and triggering defecation. The result is a bowel movement typically within 6–12 hours orally or within 15–60 minutes when given rectally.
Dosage Forms and Dosing: Bisacodyl is available as oral tablets (5 mg) and rectal suppositories (10 mg). Typical adult dosing is 5–15 mg by mouth once daily or 10 mg rectally as needed. It’s often used for acute constipation, bowel prep, or to prevent straining in specific medical situations.
Adverse Effects: Common side effects include abdominal cramping, diarrhea, and nausea. Chronic or excessive use may lead to electrolyte imbalances, dehydration, and laxative dependence.
Drug Interactions and Monitoring: Concurrent use with antacids, proton pump inhibitors, or milk may cause premature dissolution of enteric-coated tablets, leading to gastric irritation. Monitoring for bowel regularity, hydration status, and signs of electrolyte imbalance is important—especially in elderly or debilitated patients.
Senna is a stimulant laxative. Its pharmacological activity comes from natural compounds called sennosides. Metabolites act locally in the colon to stimulate peristalsis, thereby accelerating bowel movements. While osmotic laxatives are generally considered first-line laxative agents, this makes senna a useful alternative for the short-term treatment of constipation.
The pharmacokinetics of senna are unique in that its onset of action typically takes 6 to 12 hours after oral administration, reflecting the time required for colonic bacteria to metabolize sennosides into active compounds. This delayed onset makes senna better suited for bedtime dosing when overnight relief is desired.
Although senna is effective, its use carries potential adverse effects. Common side effects include abdominal cramping, diarrhea, and, rarely, electrolyte disturbances such as hypokalemia. Chronic or excessive use can lead to dependency and possibly melanosis coli, a benign but visible pigmentation of the colon lining.
Drug interactions may occur, particularly with medications affected by potassium levels, such as digoxin or diuretics. For these reasons, senna is generally recommended for short-term use, with emphasis on evaluating underlying causes of constipation before long-term therapy is considered.
On this episode of the Real Life Pharmacology podcast, I discuss Miralax (polyethylene glycol) pharmacology, adverse effects, and much more.
MiraLAX is an osmotic laxative commonly used to treat occasional constipation by retaining water in the stool to increase stool frequency and soften consistency.
The standard adult dose of MiraLAX is 17 grams (approximately one heaping tablespoon) dissolved in 4 to 8 ounces of liquid once daily.
Electrolyte imbalances are rare but possible with prolonged or excessive use of Miralax, particularly in elderly or renal-impaired patients.
Advise patients to maintain adequate hydration while using MiraLAX to support its mechanism and reduce side effects.
On this podcast episode, I finish up my breakdown of the Beers Criteria.
I cover the use of sliding-scale insulin and sulfonylureas in geriatric patients. Hypoglycemia is a major concern with both of these diabetes management strategies.
PPIs show up on the Beers criteria list as they can increase the risk of C. diff, pneumonia, fractures, and GI malignancies.
Metoclopramide has dopamine antagonist activity and can increase the risk of EPS and tardive dyskinesia.
On this podcast episode, I discuss simethicone pharmacology, adverse effects, drug interactions, and much more!
Simethicone is primarily used for anti-gas purposes. It is most often used on an as needed basis for relief of flatulence and bloating associated with gas.
Systemic absorption is minimal with simethicone so the occurrence of any systemic-type side effects at therapeutic doses is low.
Simethicone may interfere with levothyroxine absorption. Timing levothyroxine at least a few hours prior to simethicone should help reduce the significance of this interaction.
In this episode, I discuss loperamide (Imodium) pharmacology, adverse effects, and drug interactions.
Loperamide has opioid-type activity in the gut but has extremely low oral bioavailability. This allows it to be used for diarrhea but at lower doses won’t cause systemic opioid-like effects.
Loperamide abuse has been reported. Excessive dosages can increase the risk of cardiac arrest and other cardiovascular concerns.
Medication causes of diarrhea should be ruled out prior to starting a medication like loperamide. I discuss numerous medications that can cause diarrhea in this podcast.
