Monday Pharmaceutical Mystery: March 2

You are entering dermatology prescriptions for your patient, IM, from the electronic prescribing queue. After entering several topical medications, you notice the dermatologist has prescribed cimetidine for warts. Is this a mistake?

Mystery: Why is a dermatologist prescribing cimetidine for warts?

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Solution: Cimetidine (Tagamet) is an H2 antagonist, like ranitidine (Zantac) and famotidine (Pepcid). Cimetidine is indicated for treatment of duodenal ulcers, GERD, and hypersecretory conditions, such as Zollinger-Ellison syndrome.¹

Although data seems inconclusive, and recent large studies have not been published, cimetidine has been used for many years as an off-label treatment of warts. In a 3-month study, treatment with cimetidine resulted in improvement in 87% of children, and in 68% of adults.²

In following up, warts were shown to have recurred in patients who had stopped cimetidine treatment before the warts had resolved. In about 2/3 of patients whose warts had previously cleared, there was no recurrence. The authors found cimetidine to be helpful in the treatment of viral warts in adults and children.²

Another double-blind, placebo-controlled study found cimetidine not to be significantly more effective than placebo, but saw a trend toward efficacy in younger patients.³

A small, retrospective 2018 study⁴ looked at pediatric heart transplant patients that had previously been treated with high-dose cimetidine (30 mg/kg/day in two divided doses, for 3-6 months). The mechanism of cimetidine in wart treatment is activation of Th1 cells to produce interleukin (IL)-2, IL-12, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, thus improving cellular immunity and wart remission. The authors concluded that cimetidine was a safe, alternative treatment for patients with multiple warts, noting that other treatments are expensive, painful, and can cause scarring.⁴

REFERENCES

• DailyMed. Cimetidine. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=06c0a509-026f-44e0-9975-a94a8de51d43 Accessed February 1, 2020.
• Gooptu C, etal. Treatment of viral warts with cimetidine: an open-label study. Clin Exp Dermatol. 2000 May;25(3):183-5. 10.1046/j.1365-2230.2000.00608.x
• Rogers, CJ, etal. Cimetidine therapy for recalcitrant warts in adults: is it any better than placebo? J Am Acad Dermatol. 1999 Jul;41(1):123-7.
• Das BB, Anton K, Soares N, et al. Cimetidine: A Safe Treatment Option for Cutaneous Warts in Pediatric Heart Transplant Recipients. Med Sci (Basel). 2018;6(2):30. Published 2018 Apr 8. doi:10.3390/medsci6020030