Probenecid Pharmacology

Patients with G6PD deficiency who are taking probenecid are at increased risk for hemolytic anemia.

In a patient taking probenecid, they need to have adequate kidney function for the drug to work.

GI upset is likely the most common adverse effect of probenecid. It can be given with food.

Probenecid can raise the concentrations of many common antibiotics like penicillins and cephalosporins.

Remember that there are many medications that can oppose the beneficial effects of probenecid. Thiazides, niacin, and some immunosuppressants can raise uric acid.

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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.

Nicotine Patch Pharmacology

Nicotine replacement therapy is an important tool in helping our patients quit smoking. There are lots of clinical pearls involving the pharmacology of nicotine patches and I explore them in this episode.

Nicotine patches differ from the gum and other acute relief forms in that they are intended to provide a consistent level of nicotine in the body.

The initial dosing of nicotine patches is dependent upon the number of cigarettes smoked by the patient. I discuss it further in the podcast.

When applying nicotine patches, it is important to remember to utilize a clean, non-hairy area to ensure the patch adheres to the skin appropriately.

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!

Doxepin Pharmacology

Doxepin is under the class of tricyclic antidepressants. It can inhibit the reuptake of serotonin and norepinephrine.

In addition to the serotonin and norepinephrine reuptake inhibition mechanism, doxepin also has antihistamine type effects.

Because of the anticholinergic activity of doxepin, it is recommended to avoid this medication in the elderly, particularly at high doses.

Be aware that anticholinergics like doxepin can reduce the benefit of dementia medications.

CYP2D6 is an important enzyme in the metabolism of doxepin and drugs like bupropion that inhibit CYP2D6 can increase the concentrations of doxepin.

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!

Atomoxetine Pharmacology

Atomoxetine is a norepinephrine reuptake inhibitor that can be used in the management of ADHD.

Atomoxetine is a non-controlled substance option for patients seeking this alternative to traditional stimulants.

CYP2D6 is an important enzyme in the breakdown of atomoxetine.

CYP2D6 inhibition or poor metabolizers via CYP2D6 can lead to higher concentrations of atomoxetine and put our patients at greater risk for adverse effects.

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Fluoxetine Pharmacology

Fluoxetine is an SSRI used in the management of depression, anxiety, OCD, PTSD, and other psychiatric conditions.

Fluoxetine has a very long half-life which can impact clinical management. I discuss how this matters in this podcast episode.

Fluoxetine inhibits CYP2D6 which can alter the concentrations of many drugs.

Prodrugs like codeine and tamoxifen can have their effects reduced because of fluoxetine. I explain this further in the episode.

By inhibiting CYP2D6 concentrations of many drugs can be raised by the use of fluoxetine.

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Metoprolol Pharmacology

Metoprolol is a beta-blocker commonly used in the management of hypertension, heart failure, and atrial fibrillation.

There is an extended release dosage form and immediate release dosage form with metoprolol. The advantage of the extended release product is that it doesn’t require as frequent dosing.

Metoprolol is selective for beta-1 receptors. It is less likely to interact with asthma medications.

CYP2D6 plays an important role in breaking down metoprolol. Alterations in this enzyme’s activity can alter concentrations of the drug.

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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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Methylphenidate Pharmacology

Methylphenidate has an FDA approved indication for ADHD. In this podcast episode, I cover the pharmacology, adverse effects, kinetics, and drug interaction.

Because methylphenidate has stimulant type effects, it can raise blood pressure and heart rate.

Weight, blood pressure, and pulse are important monitoring parameters in patients taking a stimulant type medication like methylphenidate.

There are numerous dosage forms of methylphenidate which can help accommodate many different patients’ needs.

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Cilostazol Pharmacology

Cilostazol has antiplatelet and vasodilatory effects. Because of this, it can manage symptoms of intermittent claudication.

GI upset, headache, and edema are common adverse effects associated with the use of cilostazol.

Cilostazol is recommended to be given on an empty stomach.

In patients with heart failure, cilostazol use is contraindicated.

CYP3A4 interactions are prevalent with cilostazol. Inhibitors of CYP3A4 can increase the concentrations of cilostazol.

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Metronidazole Pharmacology

Metronidazole (Flagyl) is an antibiotic that is used for various infections.

Metronidazole can certainly cause GI upset like most antibiotics, but uniquely may also cause a metallic taste.

Metronidazole is also rarely associated with CNS changes and can induce the potential for peripheral neuropathy.

Patients should avoid alcohol with the use of metronidazole and this is on account for the possibility of a disulfiram reaction. I discuss some of the symptoms of this reaction in the podcast.

Metronidazole can substantially raise the concentrations of warfarin. INR monitor and a reduction in dose of warfarin may be necessary.

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