LAS VEGAS—Tips on potential interactions to watch between antibiotics and over-the-counter (OTC) medications, ensuring competitive athletes avoid inadvertent doping, and properly treating yeast-like organisms were among the clinical pearls presented at the ASHP 2022 Midyear Clinical Meeting & Clinical Exhibition.

Antimicrobials and OTC Medications Can Be Bad Mix

There is an overwhelming sense that OTC medications, such as antacids or nasal corticosteroids, are benign, but some can have potentially dangerous interactions with antimicrobial therapies, said David Cluck, PharmD, BCPS, BCIDP, AAHIVP, an associate professor of pharmacy practice at East Tennessee State University’s Gatton College of Pharmacy, in Johnson City.

“Interactions with newer antimicrobial therapies can fall through the cracks, especially if you’re not using them [every] day,” Dr. Cluck said. He discussed some key drug–drug interactions and other cautions to heed when using antibacterials, antifungals and antivirals.

Omadacycline (Nuzyra, Paratek), for instance, has several administration requirements, he said. Patients should fast for at least four hours before taking the drug, and take it with water. Then, they should fast for the next two hours (water is allowed), and cannot consume dairy products, antacids or multivitamins for the next four hours, according to the prescribing information. A chelation complex can form with a tetracycline derivative and calcium-containing products, Dr. Cluck explained. “There’s just a lot of places for patients to go wrong there,” he said, and patient education is critical.

Taking cefidinir with antacids can reduce the rate and extent of absorption of the drug by 40%, and concomitant administration of cefpodoxime with antacids or H2 antagonists can reduce peak plasma levels by up to 42%, and the extent of absorption by approximately 30%, according to the drug's prescribing information.

Common drug interactions to watch for with antifungals include the combination of voriconazole with omeprazole, which can increase the mean voriconazole peak concentration in plasma, Dr. Cluck said (Antimicrob Agents Chemother 2012;56:6001-6002). In addition, antacids, H2 antagonists and proton pump inhibitors (PPIs) can reduce the absorption of itraconazole capsules (Eur J Clin Pharmacol 1998-;54[2]:159-161), so a different itraconazole formulation may be needed. Taking probiotics containing Saccharomyces boulardii at the same time as fluconazole can diminish the efficacy of the probiotic.

For antivirals, pay particular attention to the combination of nirmatrelvir/ritonavir (Paxlovid, Pfizer) and OTC nasal corticosteroids such as fluticasone. Coadministration of these products, or of ritonavir with a protease inhibitor, can induce Cushing’s syndrome (J Acquir Immune Defic Syndr 2013;63[3]:355-361). Also, oral rilpivirine is contraindicated with PPIs, and baloxavir (Xofluza, Genentech) should not be taken with laxatives, antacids or oral supplements such as calcium, iron, magnesium, selenium or zinc, which can reduce the drug’s efficacy, according to the prescribing information for these products.

“If an antiretroviral or antiviral is prescribed, you should probably check for every interaction you could possibly think of,” Dr. Cluck said, which is a message he often stressed with his students. In addition, make sure to ask patients about any OTC medications or herbal supplements they take so you can properly assess risk, he noted.

Help Competitive Athletes Avoid Inadvertent Doping

Athletes have unique medication needs and, depending on their sport and level of competition, they can be held liable for any doping agents detected, said Ashley Anderson, RPh, MBA, IOC-Drugs in Sport Certified, who practices in Fort Collins, Colo. “Even with a valid prescription for legitimate medical conditions, common prescriptions like insulin, beta blockers or beta-2 agonists are prohibited in sports,” she said. “Extra steps have to be taken for a competitive athlete to get approval for use in sport.”

The medications above are examples of substances that enhance performance, violate the spirit of sport, and/or risk the athlete’s health as classified by the World Anti-Doping Agency (WADA) Code and Prohibited List. Insulin regulates metabolism and is prohibited as a metabolic modulator, including promoting uptake of glucose and amino acids into muscle. Beta-blockers are prohibited in certain sports in which athletes want to reduce tremors or decrease heart rate (e.g. shooting), and beta-2 adrenergic agonists are dose-dependent anabolic agents and sympathomimetics.

Any pharmacist can learn to identify medication restrictions for athletes to help them minimize their risks, Ms. Anderson said. She outlined five steps to follow.

1. Educate yourself.

Before working with athletes, complete designated trainings for athlete support personnel such as those offered by WADA’s Anti-Doping Education and Learning Platform, SafeSport, Drug Free Sport and HealthProAdvantage. Keep current on anti-doping rules and prohibited substances, which are updated at least annually.

2. Identify which of your patients are athletes.

What is their sport and level of competition, and when is their next big event? Look closely at the list of banned substances and any exceptions regarding dose, route and timing. For example, she said, some events might have a no-needle policy. Ask patient-athletes what education they have completed about anti-doping and the risk of using dietary supplements.

3. Confirm the substances and methods that athletes must avoid based on their sport’s anti-doping authority.

Collect a comprehensive list of drugs and dietary supplements from patients, including any vitamins or samples from the gym, and compare these to classes of drugs on the prohibited lists. When in doubt, call the anti-doping authority for clarification and help the athlete apply for approval for medical use when appropriate.

4. Understand the sensitivity of doping tests.

Even trace amounts of contaminants found in some prescription-grade pharmaceuticals have been documented to lead to a positive test result. Well-documented cases of trace amounts of diuretics causing a positive doping test in athletes taking prescription metformin, cephalexin, baclofen and other prescription drugs in the United States (Front Sports Act Living 2021;18:3:69224) and nonsteroidal anti-inflammatory drugs in Germany (Forensic Sci Int 2016;267:166-172) are just two examples. Dietary supplement use and contamination are still the biggest sources of accidental doping by athletes, Ms. Anderson said.

5. Do a supplements check.

Because dietary supplements pose such a large risk, ask patient-athletes what steps they have taken to check the quality of their supplements, if they have notified their primary care providers and team doctors, and what they understand about the risks of using the products.

Consider All Possibilities When Diagnosing From Yeast Blood Cultures

If you get a call about a patient with a positive blood culture for yeast, it’s easy to think about Candida species and recommend your institution’s preferred echinocandin. You’d be right—most of the time. But there are important exceptions that pharmacists need to remember so as not to cause patient harm, said Brian Potoski, PharmD, BCPS-AQ ID, an associate professor of pharmacy and therapeutics at the University of Pittsburgh.

Cryptococcus neoformans, from the Greek meaning “hidden” or “buried,” also can be initially identified by clinical microbiology labs as a yeast. However, the organism is resistant to echinocandins, and delays in starting therapy can contribute to poor patient outcomes, Dr. Potoski said. Appropriate therapy would be an amphotericin B product or an azole such as fluconazole (Clin Infect Dis 2010;50:291-322), he noted.

Consider that C. neoformans may be present in patients who meet the clinical definitions for HIV infection, advanced liver cirrhosis or autoimmune disease, he said, because it is an opportunistic organism. Although some advanced laboratory equipment can identify organisms quickly, “technology is not a substitute for good clinical decision-making,” Dr. Potoski cautioned. “Not every hospital or institution has those types of rapid diagnostics, and so it remains a very important hurdle.”

Another organism that could be misidentified as yeast is the mold Fusarium, he added. In this case, select voriconazole as the recommended antifungal. Patients at risk for this infection include hematopoietic stem cell transplant recipients who also may have acute or chronic graft-versus-host disease, prolonged neutropenia or donor mismatch.

The sources reported no relevant financial disclosures.