Real Life Pharmacology - Pharmacology Education for Health Care Professionals

Dexmedetomidine is a selective alpha-2-adrenergic agonist with sedative characteristics. Dexmedetomidine is commonly used in ICU and procedural sedation, as well as postoperative pain. A few of the more serious adverse effects of dexmedetomidine to keep an eye on including bradyarrhythmias/bradycardia and hypotension. Dexmedetomidine undergoes hepatic metabolism, meaning a dose reduction may be required in patients with impaired hepatic function. Major drug interactions to monitoring for with dexmedetomidine include co-administration with anesthetics, sedatives, hypnotics, and opioids, as it may lead to an enhancement of effects. It is also important to note that dexmedetomidine may produce withdrawal symptoms if used for longer than 24 hours.

On this episode, I discuss the pharmacology of calcitonin. Calcitonin has an indication for osteoporosis as well as hypercalcemia. When considering drug interactions with calcitonin, recall that it can lower calcium levels which could have a cumulative effect when combined with loop diuretics. Calcitonin nasal spray should be stored upright and primed prior to use.

Rivastigmine is an acetylcholinesterase inhibitor used in the management of certain dementias. I discuss rivastigmine pharmacology on this episode. Weight loss is a potential adverse effect of rivastigmine. It is important to monitor weights. Anticholinergic medications such as diphenhydramine can blunt the effects of rivastigmine. Rarely, acetylcholinesterase inhibitors like rivastigmine can cause bradycardia.

Caffeine is a commonly used supplement and is found in many food and beverages. I discuss caffeine pharmacology, adverse effects, and drug interactions. Caffeine can inhibit CYP1A2 and also be affected by CYP1A2 inhibitors. I discuss some examples in the podcast. It is critical to inquire about caffeine intake when patients are reporting insomnia. Caffeine has been associated with increases in pulse and blood pressure. Be sure to ask about caffeine intake when assessing these vital signs.

Colestipol is a bile acid sequestrant that can be used in the management of hyperlipidemia. By binding bile acid in the gut, colestipol can lower LDL that is bound to bile acid by eliminating it through the feces. Numerous drug interactions existed as colestipol can bind many drugs. This is a downside to its use and why it isn't a preferred hyperlipidemia agent. In patients with elevated triglycerides, colestipol should be avoided.

Metolazone (Zaroxolyn) is a thiazide-like diuretic. It promotes the loss of water and sodium through the kidney. The most common indication I see metolazone used for is for additional fluid loss in heart failure. Potassium must be monitored as it can cause significant hypokalemia which is exacerbated when metolazone is used in combination with loop diuretics. Hyperuricemia is a potential adverse effect with metolazone; this is critical to monitor for in patients at risk for gout attacks.

Ibandronate is a bisphosphonate that can be used in the management of osteoporosis. Bisphosphonates like ibandronate require a full glass of water for oral administration. Patients should remain upright for at least 30-60 minutes following taking ibandronate to help reduce the risk of esophagitis. Osteonecrosis has rarely been associated with bisphosphonates like ibandronate - I've discussed a couple of risk factors that may place a patient at higher risk.

Fluticasone, Umeclidinium, and Vilanterol is a combination medication used in the setting of COPD. I discuss the pharmacology of this agent further in this episode. Fluticasone is the inhaled corticosteroid portion of the drug while umeclidinium is a LAMA and vilanterol is a LABA medication. Drug interactions aren't incredibly common or strongly clinically significant, but I discuss some of them with Trelegy Ellipta. Having a once-daily dose can be advantageous to help improve patient adherence. Fluticasone, umeclidinium, and vilanterol comes as a once-daily combination.

Hyoscyamine is an anticholinergic medication that is primarily used for GI problems like spasms and pain associated with IBS. Because of the highly anticholinergic nature of hyoscyamine, it can cause dry eyes, dry mouth, urinary retention, and constipation. Be aware of the risk for the prescribing cascade with hyoscyamine. Saliva substitutes for dry mouth, artificial tears for dry eyes, etc. Sedation is a concern with hyoscyamine and this can be exacerbated by drugs like benzodiazepines, opioids, and older antihistamines.

Calcium Acetate (PhosLo) is used in the management of hyperphosphatemia associated with CKD. Important monitoring parameters for calcium acetate include phosphorus, calcium, PTH, and renal function. There are numerous binding interactions with calcium acetate. It can reduce concentrations of some HIV drugs, antibiotics, and thyroid supplements. I discuss more examples in the podcast. Thiazide diuretic in combination with calcium acetate may increase the risk for hypercalcemia.

Nortriptyline is a TCA that can be used for depression and various pain syndromes. I discuss other less common diagnoses in this podcast episode as well. There are a lot of drug interactions with nortriptyline. It is metabolized by CYP2D6, can have additive anticholinergic effects and has been associated with QTc prolongation. Nortriptyline is very anticholinergic and can blunt the effects of dementia medications. Dry mouth, dry eyes, sedation, urinary retention, and constipation are a few of the more common adverse effects of nortriptyline.

Hydroxychloroquine is classified as a DMARD and when used chronically, can be helpful in managing rheumatoid arthritis and Lupus. There have been reports of QTc prolongation with hydroxychloroquine. While not incredibly common, it is important to remember this consideration in patients at risk for QTc prolongation. Hydroxychloroquine is associated with causing retinopathy. Routine eye exams for monitoring purposes are critical. Rarely, hydroxychloroquine can be associated with blood disorders like neutropenia and thrombocytopenia. In addition, alterations in liver function have been reported.

Latanoprost is a prostaglandin F2 analog that can help reduce intraocular pressure and manage glaucoma. Excessive eyelash growth is a potential adverse effect of latanoprost, although some patients may appreciate this. Patients with a lighter color iris may notice that their eyes are turning more brown with the chronic use of latanoprost. Corticosteroids are known to increase intraocular pressure and potentially oppose the beneficial effects of latanoprost.

Terbinafine can inhibit CYP2D6 which plays an important role in the metabolism of many drugs such as metoprolol, fluoxetine, and clozapine. With terbinafine's ability to inhibit CYP2D6, it can also increase the risk of treatment failure with drugs like tamoxifen. When using anti-fungal drugs like terbinafine, remember that fungal infections can often require more time to treat. Terbinafine has the potential to cause liver impairment. I discuss this further on the podcast.

Alendronate is a bisphosphonate that is used in the management of osteoporosis. In this episode, I discuss osteonecrosis risk and what are some of the risk factors that may increase the chances of this very rare adverse effect. Binding interactions are so critical with alendronate. They can essentially make the drug useless. Esophageal irritation and ulceration is one of the possible complications with the use of alendronate.