Azithromycin Pharmacology

Azithromycin Pharmacology

On this episode, I cover azithromycin pharmacology. This drug primarily acts by inhibiting protein synthesis. It binds to the 50s ribosomal subunit.

GI adverse effects like nausea and diarrhea are going to be the most common with azithromycin.

Azithromycin has been associated with prolonging the QT interval. Drugs like amiodarone, ondansetron, citalopram, antipsychotics, and quinolone antibiotics can also prolong the QT interval.

One major advantage that azithromycin has over other antibiotics is that it has a long half life which allows for once daily dosing.

Azithromycin has numerous uses like pneumonia, MAC, alternative for ear infections in patients with a beta-lactam allergy, certain STD’s, and also is rarely used in long term COPD exacerbation prevention.

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Rivaroxaban Pharmacology

Rivaroxaban is a factor 10a inhibitor that inhibits clot formation and thins the blood.

Rivaroxaban needs to be monitored for bleed risk. Checking periodic CBC can help us assess if hemoglobin and hematocrit are remaining stable.

Enzyme inducers like rifampin, St. John’s Wort, and carbamazepine can reduce concentrations and increase the risk of treatment failure.

NSAIDs and antiplatelet medications can significantly increase the risk of bleed with rivaroxaban.

Rivaroxaban should not be used with dual P-glycoprotein and CYP3A4 inhibitors. Examples include ketoconazole, itraconazole, and ritonavir.

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Valproate Pharmacology

Valproate Pharmacology

Valproate (valproic acid, Depakote) has numerous uses which includes migraines, seizures, and bipolar disorder.

In a patient who is taking valproate, it is important to monitor for signs and symptoms of confusion as this drug can cause elevated ammonia levels.

When switching between dosage forms of valproate, you must recognize that the bioavailability is not the same between each different dosage form. This could lead to toxicity or treatment failure.

Valproic acid has a boxed warning for hepatotoxicity and liver function needs to be monitored.

Valproic acid can increase lamotrigine levels which ultimately could lead to an increased risk of lamotrigine induced SJS.

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Donepezil Pharmacology

On this episode I discuss the pharmacology of donepezil.

Donepezil is an acetylcholinesterase inhibitor. In dementia, that is a deficiency in acetylcholine and donepezil helps preserve this neurotransmitter.

Donepezil can cause weight loss, GI upset, and diarrhea. This is an important monitoring parameter in our dementia patients.

There is the possibility for donepezil to cause bradycardia and insomnia. Keep an eye out for these adverse effects as they can and do happen in real practice.

Anticholinergics are notorious for blunting the effects of donepezil. We must look out for drug interactions from older anticholinergics like diphenhydramine, amitriptyline, and hydroxyzine.

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Linezolid Pharmacology

linezolid pharmacology

Linezolid is an antibiotic used for bacterial infection. It primarily works by inhibiting bacterial protein synthesis.

Linezolid is primarily bacteriostatic against most bacteria which means that it inhibits the growth and doesn’t necessarily kill the bacteria itself.

Caution must be used with linezolid and serotonergic drugs as there is a risk for serotonin syndrome. Clinical risk/benefit analysis needs to be done.

Linezolid overall has good coverage for VRE and MRSA. It is an option for MRSA pneumonia where daptomycin is not.

Linezolid has both an oral and an IV option which allows for good continuity of inpatient and outpatient use.

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Pioglitazone Pharmacology

pioglitazone pharmacology

On this episode, I cover pioglitazone pharmacology. The primary mechanism of action with pioglitazone is that it is an agonist at Peroxisome Proliferator Activated Receptor Gamma receptor. This improves insulin sensitivty in the periphery.

Two common side effects exist with pioglitazone. This drug can cause weight gain and also contribute to edema.

Pioglitazone has a boxed warning and is contraindicated in patients who have symptomatic heart failure.

There are a few potential interactions with pioglitazone. Trimethoprim and gemfibrozil can inhibit the breakdown of pioglitazone.

A couple of advantages of pioglitazone include that it is generic (inexpensive) and that it is dosed once daily.

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Nitrofurantoin Pharmacology

On this episode I breakdown nitrofurantoin pharmacology. Nitrofurantoin is an antibiotic that is used in the treatment of UTI’s.

Nitrofurantoin has activity by creating reactive metabolites that can disrupt protein synthesis and ultimately kills the bacteria causing the infection.

It is important to remember with nitrofurantoin, that in the setting of systemic infection and/or kidney involvement, the drug may not be very effective.

Nitrofurantoin can potentially reduce the effectiveness of certain vaccines. Be sure to look this up prior to administration.

Nitrofurantoin can cause pulmonary symptoms as well as neuropathy. This is very important to monitor for.

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Hydralazine Pharmacology

Hydralazine Pharmacology

Hydralazine Pharmacology

Hydralazine works as a direct vasodilator. It primarily works on the arterioles versus the venous system.

Hydralazine can cause a unique adverse reaction. It can cause a Lupus type syndrome that can result in fever, myopathy and symptoms that mimic arthritis.

I discuss drug interactions with hydralazine and how you need to be aware of certain medications that can have additive effects and also those that can oppose the effects of the drug.

One of the downsides to using hydralazine is that patients don’t like to take it as often as it requires. It is typically dosed three to four times per day.

Orthostasis is a risk with any drug that reduces blood pressure and hydralazine is no different.

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Aspirin Pharmacology

Aspirin Pharmacology

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

The two most common adverse effects with aspirin are GI upset and increasing the risk for bleeding and bruising.

A commonly asked test question about aspirin is whether it can be used in pediatrics and what risk we encounter if we use it.

Another rare effect with aspirin is tinnitus which I discuss further on this episode.

It is critical to pay attention to other medications that can thin the blood in a patient taking aspirin. Examples include anticoagulants like warfarin, apixaban, rivaroxaban; antiplatelets like clopidogrel or prasugrel; or NSAIDs.

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Clonidine Pharmacology

Clonidine is classified as an antihypertensive. Clonidine pharmacology involves having agonist activity at central alpha 2 receptors. This leads to lower sympathetic outflow and a reduction in blood pressure.

Clonidine has numerous reported uses in addition to its antihypertensive effect. It can potentially be used for ADHD, menopausal type symptoms, and opioid withdrawal.

Clonidine has historically been on the Beers’ list of drugs as it can cause some CNS side effects like sedation, dizziness, and rarely delirium.

Clonidine is unique in the antihypertensive class as it does have a patch formulation.

Because of the blood pressure lowering effect of clonidine, we have to be aware of patients who report dizziness. Monitoring is critical.

Clonidine can also lower heart rate and contribute to dry mouth. Keep an eye out for drugs that can have a cumulative effect on these symptoms.

Drugs like beta-blockers, non-DHP CCB’s, and digoxin can all have a cumulative effect with clonidine and lower pulses. Monitoring is important.

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