Phenoxybenzamine (Dibenzyline)

Phenoxybenzamine, a long-acting, adrenergic, alpha-receptor blocking agent, can increase blood flow to skin, mucosae, and abdominal viscera, as well as lower supine and standing blood pressures. The initial dose is 10 mg of Dibenzyline (phenoxybenzamine hydrochloride) bid with increases once daily, usually up to 20-40 mg 2-3 times/days.

Discussion

McGuire et al. (1976) reported that hypertension, headache, and anxiety of AD could no longer be provoked with bladder filling (but sweating continued to occur) in the six participants who took phenoxybenzamine (dose range from 10 to 20mg) daily. However, this result is opposite to Lindan et al.’s (1985) findings where blood pressure rose with bladder distension in ten participants and remained at baseline in only two participants after taking phenoxbenzamine for 4 or more days.

Conclusion

There is level 4 evidence (from one pre-post study and one case series study) for use of Phenoxybenzamine in the management of AD; however, the results are conflicting with no effects seen in one study (Lindan et al. 1985) and positive effects in another (Lindan et al. 1985; McGuire et al. 1976).