Rabbit Syndrome Due to Topical Minoxidil Foam

The document reports two cases of rabbit syndrome, a rare movement disorder characterized by involuntary, rapid movements of the perioral muscles, following the use of 10% minoxidil foam for male pattern hair loss (MPHL). Both patients applied significantly higher doses than prescribed, which led to the development of symptoms shortly after starting the treatment. No other concurrent medications or relevant medical or family history were reported. Upon reducing the dosage to the proper amount (1 mL) of topical minoxidil lotion, both patients' symptoms resolved. The document suggests that the large amount of systemically absorbed minoxidil and its potential to activate a subtype of dopamine receptors may be responsible for the observed rabbit syndrome. This is the first report of minoxidil-induced rabbit syndrome, and the temporal relationship between the drug's use and symptom onset and resolution indicates minoxidil as the likely cause.