What Antifungal Medication Should This Patient Be Prescribed

What antifungal medication(s) should this patient be prescribed, and for how long?

In accordance with the American Academy of Family Physicians (AAFP) and Centers for Disease Control and Prevention (CDC) guidelines, the first-line treatment for onychomycosis, particularly proximal subungual onychomycosis as seen in this patient, is systemic antifungal agents such as terbinafine or itraconazole. Among these, terbinafine is often preferred due to its efficacy and safety profile, particularly for uncomplicated cases of toenail onychomycosis. The medication should be prescribed after confirming the diagnosis with a positive fungal culture, which has been accomplished in this case.

Given that the patient has no contraindications such as hepatic impairment, and considering her comorbidities like diabetes mellitus, terbinafine is an appropriate choice. The typical course of therapy for toenail onychomycosis with terbinafine is 12 weeks (Gupta et al., 2019). Efficacy of terbinafine is optimized with adherence to this duration, with some evidence recommending up to 12 weeks of daily therapy, as partial clearance begins around this period (Mekkes et al., 2017). Indeed, longer courses may be necessary for more severe or resistant infections, but 12 weeks remains standard for uncomplicated cases.

A sample prescription would be as follows:

Vital Medical Center 8300 West Flagler ST suite 170 Miami, Florida


INITIALS. ARNP


Patient Name: E.D.


DOB: XX/XX/1985


Terbinafine (250 mg tablets) Disp: 90 tablets (ninety)


Sig: Take 1 tablet (250 mg) by mouth once daily for 12 weeks for onychomycosis treatment.


No refills.


INITIALS, ARNP


Date: [Insert date]

Alternatively, itraconazole could be prescribed at a dose of 200 mg twice daily for one week per month for two months, but terbinafine remains the preferred initial therapy due to its favorable safety profile and evidence base.

What labs for baseline and follow-up of therapy would you order for this patient? Give rationale.

Prior to initiating systemic antifungal therapy, baseline laboratory assessments are essential to prevent potential adverse effects, especially hepatotoxicity, which is a known risk associated with terbinafine. The primary labs recommended include hepatic function tests (LFTs) — specifically serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin. These measurements establish a baseline for comparison if hepatotoxicity develops during treatment (Gupta et al., 2019).

In addition, a complete blood count (CBC) may be ordered initially to assess for any underlying hematologic abnormalities, although terbinafine rarely affects the blood count, it is especially pertinent for patients with other risk factors or comorbidities. Because this patient has diabetes, monitoring is important as diabetics are more prone to complications and poorer healing outcomes.

Follow-up labs should be scheduled during treatment: at 6-week intervals to monitor liver function, given that hepatotoxicity can develop insidiously. If the patient develops symptoms such as jaundice, fatigue, or abdominal pain, immediate assessment is necessary. Rechecking hepatic enzymes helps to detect early signs of adverse effects, allowing for prompt intervention including discontinuation of medication if needed.

Furthermore, considering her history of diabetes and obesity, monitoring blood glucose levels, liver enzymes, and renal function periodically during therapy is prudent. It is also beneficial to counsel the patient on signs of hepatotoxicity, such as fatigue or dark urine, and advise her to avoid alcohol, which can exacerbate hepatic strain (Gupta et al., 2019).

In summary, initial labs should include hepatic function tests (ALT, AST, bilirubin) and potentially CBC, with follow-up testing every 6 weeks. These assessments aim to mitigate the risk of drug-induced hepatotoxicity and other adverse effects, ensuring safe administration of systemic antifungal therapy.

References

  • Gupta, A. K., Rich, P. B., & Tosti, A. (2019). Onychomycosis. Journal of the American Academy of Dermatology, 80(5), 1204-1210. https://doi.org/10.1016/j.jaad.2018.12.085
  • Mekkes, G., van de Sande, L. B., & Pasch, M. C. (2017). Systemic treatment options for fungal nail infections: a review. Mycoses, 60(10), 685-697. https://doi.org/10.1111/myc.12736
  • National Library of Medicine. (2020). Terbinafine. PubChem Compound Summary. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Terbinafine
  • Centers for Disease Control and Prevention. (2020). Treating onychomycosis: A comprehensive review. CDC Publications. https://www.cdc.gov
  • Korayem, M., & Willen, M. R. (2021). Management of Onychomycosis. Journal of Fungal Infections, 2(1), 22-30. https://doi.org/10.1097/INF.0000000000000604
  • Rontogianni, D., Samonis, G., Maraki, S., & Paschos, K. (2018). Oral antifungal therapy for onychomycosis: Efficacy and safety. Clinical Microbiology and Infection, 24(8), 883-889. https://doi.org/10.1016/j.cmi.2018.04.023
  • Boyd, A., Baran, R., & Kircik, L. (2015). An update on the management of onychomycosis. Journal of Clinical and Aesthetic Dermatology, 8(12), 17-24.
  • Roh, M., Heller, D., & Kircik, L. (2020). Systemic therapy for onychomycosis. American Journal of Clinical Dermatology, 21(2), 219-229. https://doi.org/10.1007/s40257-019-00477-9
  • Schmidt, J. C., et al. (2021). Monitoring hepatic function during antifungal therapy. Journal of Clinical Pharmacology, 61(2), 217-223. https://doi.org/10.1002/jcph.1820
  • Catalfamo, L., & Van Voorhees, A. (2019). Managing side effects of systemic antifungal therapy. Journal of the American Academy of Dermatology, 80(6), 1643-1644. https://doi.org/10.1016/j.jaad.2018.12.022

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