Azathioprine Pharmacology

On this episode, I discuss azathioprine pharmacology, adverse effects, monitoring parameters, and drug interactions.

Azathioprine is classified as an immunosuppressive agent so it is naturally going to be used for autoimmune type disorders and transplantation.

Azathioprine has a boxed warning for myelosuppression. I talk more about this in the episode.

Genetic testing is recommended by the AGA prior to the use of azathioprine. I discuss which tests might be helpful to reduce the risk of toxicity.

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Cetirizine Pharmacology

On this episode of the Real Life Pharmacology Podcast, I discuss cetirizine pharmacology.

Cetirizine, commonly known as Zyrtec, is a 2nd generation antihistamine. Compared to 1st generation antihistamines, like diphenhydramine and chlorpheniramine, 2nd generation antihistamines have fewer anticholinergic effects. Pharmacologically, cetirizine works by selectively blocking histamine from binding to the H1 receptor. The uses for cetirizine are allergic rhinitis, itching, and sometimes acute allergic reactions. Commonly, cetirizine is dosed at 10 mg daily, and can even be escalated to 10 mg twice daily in rare situations. In adults 77 years old and older, the manufacturer recommended dose tops out at 5 mg daily. There are also liquid and chewable formulations for children. 

The adverse drug reactions cetirizine are mostly dose-dependent and related to its pharmacology. Out of all of the 2nd generation antihistamines, like fexofenadine and loratadine, cetirizine is the most sedating. Other adverse drug reactions related to its anticholinergic effects are urinary retention, constipation, confusion, fatigue, and dizziness. Lab monitoring is not necessary when taking cetirizine. It is important to monitor the adverse drug reactions when taking cetirizine, as well as improvement in the signs and symptoms of what it’s used for. 

Cetirizine does not undergo metabolism through liver CYP enzymes, so drug-drug interactions involving those enzymes are uncommon. The interactions that are concerning are additive effects of cetirizine’s adverse drug reactions. Drowsiness can be compounded when cetirizine is taken with opioids, sleep medications, alcohol, or other older anticholinergics with sedative effects. There is also a risk of an increased anticholinergic burden when taking medications like Cogentin, oxybutynin, TCAs, and inhaled anticholinergics. 

The manifestation of overdoses will vary depending on age. In adults, the most common observation made was sedation and somnolence. In children, restlessness and irritability were observed initially, then drowsiness. Cetirizine is not removed by dialysis. When treating overdoses, the symptoms that manifest should be treated.  

Show notes provided by Chong Yol G Kim, PharmD Student.

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Vitamin B12 Pharmacology

On this episode, I cover clinical tips and practice pearls surrounding vitamin B12 pharmacology.

Vitamin B12 deficiency plays a critical role in the development of macrocytic anemia.

There are medications that you have to be aware that can deplete vitamin B12. Metformin, colchicine, and PPIs are some common examples.

A lack of intrinsic factor can lead to B12 deficiency. Intrinsic factor is necessary for adequate GI absorption of vitamin B12.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Study Materials For Pharmacists and Students

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Fexofenadine Pharmacology

Fexofenadine is a 2nd generation antihistamine that is primarily used for allergic rhinitis. I cover fexofenadine pharmacology on this podcast episode.

Fruit juices can actually impair the absorption of fexofenadine and increase the risk of treatment failure.

Fexofenadine is mildly anticholinergic but overall has low to no CNS penetration.

Because fexofenadine has low CNS penetration, the risk for sedation and dizziness is much lower than older antihistamines like diphenhydramine.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Cyclosporine Pharmacology

cyclosporine pharmacology

On this episode, I discuss cyclosporine pharmacology. This medication is an immunosuppressant used to reduce the risk of transplant rejection.

Cyclosporine has a long list of potential adverse effects such as hyperglycemia, renal impairment, GI toxicity, and hypertriglyceridemia.

Important monitoring parameters for cyclosporine include drug levels, electrolytes, renal function, and blood sugars.

CYP3A4 interactions are critical with cyclosporine. Inhibitors can raise concentrations and inducers can lower concentrations.

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Tacrolimus Pharmacology

On this episode, I discuss tacrolimus pharmacology. This medication is an immunosuppressant used to reduce the risk of transplant rejection.

Tacrolimus has a long list of potential adverse effects such as hyperglycemia, renal impairment, GI toxicity, and hypertriglyceridemia.

Important monitoring parameters for tacrolimus include drug levels, electrolytes, renal function, and blood sugars.

CYP3A4 interactions are critical with tacrolimus. Inhibitors can raise concentrations and inducers can lower concentrations.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Diphenhydramine (Benadryl) Pharmacology

Diphenhydramine is a first generation antihistamine that is highly anticholinergic.

When using medications like diphenhydramine, be sure to watch for side effects like dry eyes, dry mouth, constipation, urinary retention, and CNS changes.

Sedation is a primary effect of diphenhydramine. It can be advantageous in certain situations, and detrimental in others.

Drugs like donepezil, memantine, laxatives, tamsulosin, and artificial tears can be indicators of anticholinergic side effects from diphenhydramine.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Epoetin Alfa Pharmacology

Epoetin alfa is essential exogenous erythropoetin which can stimulate the production of red blood cells.

It is critical to ensure adequate iron stores when using EPO.

Risks for blood clots, strokes and heart attacks are critical to recognize with the use of epoetin.

Dosage adjustments with epoetin are typically made with respect to the amount of change in hemoglobin. I discuss this further in the podcast.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Mometasone Pharmacology (Nasal and Oral Inhalation)

Mometasone is an inhaled corticosteroid and a nasal corticosteroid. The inhaled steroid is called Asmanex by brand name and the nasal version is Nasonex.

Nasonex is primarily used in the management of allergic rhinitis and can help with nasal congestion type symptoms.

Remember that nasal mometasone takes a little while to have its full effect. It can take up to a week or two to provide its maximum benefit.

Systemic absorption of both nasal and oral inhalation mometasone is very low at less than 1%.

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Montelukast Pharmacology

Montelukast Pharmacology

On this episode, I discuss montelukast pharmacology

Montelukast is a leukotriene receptor antagonist. Leukotrienes play an important role in causing inflammation and smooth muscle contraction in asthma and allergic rhinitis.

Because montelukast blocks the effects of leukotrienes, it can be advantageous to use this medication for allergies and asthma.

It is important to remind patients that montelukast is NOT a substitute for an acute relief medication like albuterol in the management of asthma symptoms.

Montelukast has been reported to cause mood and behavioral changes and it is important to monitor our patients for these rare concerns.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!