THE EFFECTS OF SINGLE DOSE ORAL HYDRALAZINE ON BLOOD-FLOW THROUGH HUMAN LUNG-TUMORS

Hydralazine has been shown to reduce tumour blood flow and to potentiate the cytotoxicity of melphalan and bioreductive agents in mice. In order to determine whether such a strategy might have clinical potential, a study was undertaken to investigate the effects of hydralazine on blood flow through human tumours. Twenty-two patients with carcinoma of the bronchus received a single oral dose of hydralazine in the range 25 to 150 mg (0.37-2.86 mg/kg) according to age and acetylator status. Tumour blood flow was assessed by single photon emission computed tomography (SPECT) performed 10 min following intravenous 99Tcm-HMPAO on two occasions 2-8 days apart, the second being performed 60 min after hydralazine administration. In 20 evaluable patients, hydralazine caused a 38% increase in blood flow through the whole tumour (p = 0.007) and a 28 % increase in flow through the tumour centre (p = 0.03) with greater increases occurring in patients sustaining greater falls in peripheral resistance. Tumour vascular resistance fell indicating active vasodilation in arterioles supplying tumours. Side-effects due to hydralazine were reported by eight patients. © 1990.