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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

Caution When Combining Fluoroquinolones and Corticosteroids

The US Food and Drug Administration (FDA) first required a black-box warning regarding the increased risk for tendonitis and tendon rupture with use of fluoroquinolones for product labels in 2008. Subsequent evidence indicates that the risk is heightened with concomitant use of corticosteroids.[1] A population-based, case-control study found that use of the two agents together was associated with a threefold increased risk for tendon rupture, and a 43-fold greater risk for Achilles tendon rupture.[2]

If possible, avoid the combination—particularly in elderly patients with renal insufficiency or other risk factors. There will certainly be clinical scenarios in which the clinician has no choice but to use the fluoroquinolone. When this combination must be used, it is important to discuss this potential complication with the patient. Monitor patients receiving this combination carefully for signs of tendon injury. If symptoms occur, discontinue the agents and minimize activity until they resolve.[3]

In July 2018, the FDA strengthened the black-box warning for fluoroquinolones because of concerns about the drug's potential mental health side effects and risk for coma with hypoglycemia. Full details are available here.

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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

Double the Drug, Not the Dose

Until recently, the clinical mantra in treating patients with hypertension was that the first antihypertensive medication should be prescribed at maximum dose before a second medication is added. A meta-analysis published almost 10 years ago examined the efficacy of adding a second medication compared with maximizing a single drug to reach target blood pressure.[4] The study concluded that the "extra blood pressure reduction from combining drugs from 2 different classes is approximately 5 times greater than doubling the dose of one drug." Just as important, risk for adverse effects may be reduced using lower-dose combination therapy.

The Eighth Joint National Committee (JNC 8)[5] guideline, published in 2014, gave clinicians the option of increasing dose of the first agent, adding a second agent, or starting treatment with two drugs for hypertension management. For patients with stage 2 hypertension, the 2017 guideline from the American College of Cardiology (ACC) and American Heart Association (AHA)[6] recommends initiation of two first-line antihypertensive drugs from different classes when the average systolic blood pressure is 20 mm Hg over target and/or the diastolic blood pressure is 10 mm Hg over target.

The bottom line is that if you need to lower blood pressure by quite a bit to reach goal, you are unlikely to reach it by increasing the dose of a single agent. You are more likely to reach your goal by adding another agent of a different class. One important caveat, however, is provided in the ACC/AHA guideline: "Simultaneous use of an ACE [angiotensin-converting enzyme] inhibitor, ARB [angiotensin receptor blocker], and/or renin inhibitor is potentially harmful and is not recommended to treat adults with hypertension."[6]

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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

There Are Easier Options Than Acyclovir for Herpes Zoster

Oral acyclovir, famciclovir, and valacyclovir have all been demonstrated in clinical trials to reduce viral shedding and accelerate resolution of symptoms (eg, pain) in uncomplicated herpes zoster. However, in order for acyclovir to achieve optimal plasma concentrations, the drug has to be given five times a day.[7] It is exceedingly difficult for patients to take a drug five times a day, particularly the elderly, who constitute the majority of infected patients.

Valacyclovir, administered three times daily for herpes zoster, is a prodrug of acyclovir and produces serum acyclovir levels that are three to five times higher than those achieved with oral acyclovir. Famciclovir, a prodrug of penciclovir, is also administered three times daily for herpes zoster.[8]

For more on treatment of herpes zoster, click here.

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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

Think Before You Thiazide

Although thiazide diuretics are an excellent option for the treatment of hypertension, there has been concern that they are less effective in patients with chronic kidney disease (CKD), especially those with a glomerular filtration rate less than 30 mL/min/1.73 m2. That concern has been challenged.[9-11] One small study found that chlorthalidone may be useful for blood pressure control in moderate to advanced CKD.[12] The 2017 ACC/AHA guideline for treatment of hypertension, however, continues to warn that loop diuretics are preferred in patients with moderate to severe CKD.[6]

An adverse effect associated with thiazide diuretics is hyponatremia. This risk is increased, and the hyponatremia can be more severe, when prescribed to elderly patients who are also taking drugs (eg, selective serotonin reuptake inhibitors) that affect water homeostasis; electrolyte monitoring is wise.[13,14]

For more information, watch this Medscape interview with Dr Rajiv Agarwal.

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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

ACEI/ARBs Plus Diuretics Interact With NSAIDs

Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) with diuretics and an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) may increase the risk for kidney injury. A retrospective cohort study found that this triple therapy was associated with an overall 31% higher risk for acute kidney injury; risk was highest at the start of treatment.[15]

Blood pressure and serum creatinine should be monitored in patients on this combination, particularly during the first few months of therapy.[16]

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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

Consider Dual Antithrombotic Therapy After PCI in AF

Patients receiving coronary artery stents are routinely treated with dual antiplatelet therapy (usually aspirin and clopidogrel) for 6-12 months.[17] Some of these patients are already on warfarin, an anti-Xa inhibitor (eg, rivaroxaban or apixaban), or a direct thrombin inhibitor (eg, dabigatran) because they have a separate indication for atrial fibrillation (AF). These patients often end up on triple therapy after the stent placement and are at risk for serious bleeding complications. But is triple therapy really required?

The randomized, controlled WOEST trial[18] compared the safety and efficacy of double versus triple antithrombotic therapy after percutaneous coronary intervention (PCI). The investigators concluded that clopidogrel without aspirin was associated with a significant reduction in bleeding complications and no increase in the rate of thrombotic events compared with triple therapy.

In 2018, a meta-analysis[19] that included four randomized controlled trials found a 47% reduction in major or minor bleeding with dual antithrombotic therapy compared with triple antithrombotic therapy with no statistically significant difference in major adverse cardiac events or stent thrombosis in patients with AF after PCI.

Although the recommendation for triple therapy in patients with AF after coronary stenting is based on expert opinion,[17] such trials as RE-DUAL PCI and PIONEER AF-PCI are bolstering support for dual antithrombotic therapy in patients with AF after PCI.

One more caution: A recent analysis of the RE-LY trial determined that concomitant use of NSAIDs and oral anticoagulants in patients with AF increases the risk for major bleeding and stroke.

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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

Drug-Drug Interactions Alter Absorption

Absorption of oral drugs can be altered by other drugs in more ways than one. Here are just a few examples:

  • Some drugs alter pH.
    • Ideally, itraconazole capsules should be taken with a full meal.[20] Concomitant administration of proton pump inhibitors (PPIs) or H2 receptor antagonists (eg, famotidine and ranitidine) leads to higher stomach pH and impaired absorption of itraconazole capsules.[21] Administer the PPI or H2 antagonist at least 1 hour before or 2 hours after itraconazole capsules.[20] (However, itraconazole solution should be taken on an empty stomach.[22])
  • Some drugs speed up gastric motility.
    • Metoclopramide may accelerate gastric emptying and subsequently decrease the absorption of digoxin.[23] This may necessitate an increase in digoxin dose.[24]
  • Some drugs bind others.
    • Iron and calcium can bind levothyroxine in the gastrointestinal tract if taken at the same time[25,26] and should be separated from levothyroxine by at least 4 hours.[27] Even milk may impair absorption of levothyroxine.[28] It is recommended that levothyroxine be taken 30-60 minutes before breakfast.[27]
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Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

No Nitrofurantoin for Pyelonephritis

Nitrofurantoin has long been first-line therapy for cystitis. However, because it does not achieve adequate tissue levels outside of the bladder, it should not be used to treat pyelonephritis.[29] The 2010 guideline from the Infectious Diseases Society of America and the European Society of Microbiology and Infectious Diseases includes several possible antibiotic regimens for pyelonephritis; ideally, selection should be guided by culture and local antibiotic resistance patterns.

For more on treatment of acute pyelonephritis, click here.

Image from Medscape. Adapted from Claxton AJ, Cramer J, Pierce C. Clin Ther. 2001;23:1296-1310.[30]

Common Prescribing Blunders: Are You Making Any of These?

Douglas S. Paauw, MD; Joanna M. Pangilinan, PharmD; Laurie Scudder, DNP, NP | August 13, 2018 | Contributor Information

Avoid Prescribing Complicated Regimens

Prescribing a drug is only half—maybe less than half—of the process of treating any condition. The other, more important part is the issue of patient adherence. Clinicians who do not try to simplify drug regimens for their patients are much less likely to have patients who are responding well to any therapy. Adherence with any medication regimen decreases with the number of doses prescribed. Although that advice is not new, it is worth repeating. A 2001 systematic review[30] that included 76 separate studies found that mean dose-taking adherence was 71% ± 17% and declined as the number of daily doses increased.

A subsequent systematic review,[31] this one including 20 clinical trials conducted in patients with chronic disease, confirmed these results. All studies reported higher adherence rates in patients using less frequently dosed medications, with once-daily dosing associated with the highest adherence rates.

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Common Drug Side Effects and Drug-Drug Interactions in Elderly Adults in Primary Care

This article offers a summary of the most commonly prescribed drugs encountered in primary care in the elderly population, their side effects, and important drug-drug interactions.Journal Articles, July 2017
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