Glycopyrrolate is an anticholinergic medication commonly used to reduce excessive secretions, particularly in palliative care, postoperative settings, and certain neurologic conditions. It works by blocking acetylcholine at muscarinic receptors, which decreases salivary and respiratory secretions. Clinically, glycopyrrolate is often used to manage terminal respiratory secretions (“death rattle”).
Adverse effects of glycopyrrolate are primarily related to its anticholinergic properties. These may include dry mouth, constipation, urinary retention, blurred vision, tachycardia, and decreased sweating. While it has fewer central effects than agents like scopolamine, caution is still warranted in patients with glaucoma, gastrointestinal obstruction, or significant urinary retention risk. Monitoring hydration and bowel function is important, especially in elderly or frail patients.
Dosing strategies depend on the clinical need. In palliative care, low doses may be given subcutaneously or intravenously every 4–6 hours as needed, while oral dosing is common for chronic sialorrhea.
Clinicians should consider the patient’s overall medication burden, as cumulative anticholinergic load can worsen cognitive impairment and contribute to falls or constipation. I discuss drug interactions and other commonly used medications that may contribute to anticholinergic burden.
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Bisacodyl (Dulcolax) Pharmacology
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.
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Fludrocortisone (Florinef) Pharmacology
On this podcast episode, I cover fludrocortisone. Fludrocortisone is a synthetic corticosteroid with potent mineralocorticoid activity and minimal glucocorticoid effects. It works primarily by promoting sodium reabsorption and potassium excretion in the distal renal tubules, leading to increased water retention and expansion of extracellular fluid volume. This pharmacologic action helps maintain blood pressure and electrolyte balance.
Fludrocortisone is most commonly indicated for the treatment of adrenocortical insufficiency, such as Addison’s disease, and for managing orthostatic hypotension by enhancing vascular tone and volume status.
Adverse effects are typically related to its mineralocorticoid potency and may include hypertension, edema, hypokalemia, and weight gain. Long-term use can also lead to complications such as heart failure exacerbation, osteoporosis, and mood changes. Because of its sodium-retaining effects, careful monitoring of blood pressure, electrolytes, and signs of fluid overload is recommended during therapy.
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10 Common Examples of The Prescribing Cascade
One of the most important yet often overlooked concepts in pharmacology is the prescribing cascade. It occurs when a new medication is prescribed to treat a side effect caused by another drug, without realizing that the first medication is the root cause. This leads to a chain reaction of additional prescriptions, unnecessary complexity, and often, new adverse effects.
Prescribing cascades can sneak up on even the most careful clinicians. A patient develops a new symptom after starting a medication—perhaps swelling, dizziness, or urinary changes—and instead of identifying the drug as the culprit, another medication is added to manage the symptom. Over time, this cycle contributes to polypharmacy, drug interactions, and reduced quality of life.
These cascades are particularly concerning in older adults, where multiple comorbidities and high medication counts make it easy for adverse effects to be misinterpreted as new conditions. But they can occur at any age and in any clinical setting.
The key to preventing prescribing cascades is maintaining a critical mindset:
Assume any new symptoms could be an adverse effect.
Review the timing of medication changes relative to the onset of symptoms.
Consider deprescribing or adjusting doses before adding new drugs.
Encourage thorough medication reconciliation and communication across providers.
Recognizing and interrupting the prescribing cascade is one of the simplest and most impactful ways we can improve medication safety. In this podcast, I share some of my favorite real-world examples that illustrate just how easily these cascades can happen.
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Airsupra (Albuterol/budesonide) Pharmacology
Airsupra is a combination inhaler that contains albuterol and budesonide, approved for as-needed use in adults with asthma. It represents the first rescue inhaler to combine a short-acting beta-2 agonist (SABA) with an inhaled corticosteroid (ICS) in a single device. The albuterol component provides rapid bronchodilation by relaxing airway smooth muscle, while budesonide works to reduce airway inflammation and mucus production. This dual mechanism allows Airsupra to not only relieve acute bronchoconstriction but also address the underlying inflammatory process that contributes to asthma exacerbations.
Clinically, Airsupra is indicated for as-needed treatment or prevention of bronchoconstriction in adults with asthma, but it is not approved for COPD. The typical dosing is two inhalations as needed, with a maximum of six doses (12 inhalations) in a 24-hour period.
The rationale for its use aligns with recent asthma guideline updates, which emphasize minimizing SABA-only use because it fails to address inflammation and may contribute to worse outcomes over time.
Common adverse effects include tremor, nervousness, tachycardia, and hypokalemia from albuterol, as well as oral thrush and hoarseness from budesonide. Patients should rinse and spit after each use to reduce the risk of oral candidiasis.
Drug interactions can occur with non-selective beta-blockers, which may blunt albuterol’s effects. CYP3A4 also plays a role in budesonide metabolism. Systemic absorption typically isn't too much of an issue with infrequent use.
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Ireland