Midodrine hydrochloride is a potent peripherally-acting α1 agonist that is well absorbed and rapidly metabolized to its active metabolite. It has been used for the treatment of refractory syncope but has the important side effect of supine hypertension. A 10-year-old boy with severe symptomatic orthostatic hypotension was treated with midodrine. After therapy, syncope attacks ceased but he suffered nighttime headaches, nausea, transient rash and itchy/prickly scalp. Midodrine was discontinued when supine hypertension was noticed. However, his supine hypertension continued until day 19 after discontinuation. This case shows that patients receiving midodrine should be observed for supine hypertension for a prolonged period.