Effect of Menthol on Dyspnea During Exercise in Individuals With COPD.

Only 21 patients were studied, and the paper states the design was nonblinded and open, so expectation could affect breathlessness ratings. The three sessions were analyzed in a fixed order, with menthol only in the second session, so familiarization with the cycle ergometer could contribute to the differences. The menthol dose was not standardized; patients applied it until they smelled it, the scent faded in less than 10 minutes, and reapplication was often needed. The responder analysis had 7 responders, 7 partial responders, and 7 nonresponders, and only oxygen flow during effort differed significantly between responders and nonresponders (P = .04). The paper notes that long-term effects, habituation, optimal dosing, timing, and administration method still need study. Participants had different reasons for admission, including exacerbation, pretransplant, postoperative care, and stable respiratory rehabilitation. Patients with exercise contraindications or anosmia were excluded, so the results may not apply to patients who cannot exercise or cannot smell menthol.

The investigators reported no financial or nonfinancial disclosures.

Do not conclude that menthol reliably reduces breathlessness in COPD. The study was open-label, the menthol session always came second, the dose was not standardized, and only 21 patients were studied.