Abstract
Nicotinamide is an agent that has been shown to be capable of enhancing radiation damage in a variety of murine tumours with both single and fractionated radiation treatments (Horsman et al.,1989b; Kjellen et al.,1991). The mechanism of action of this drug is not entirely understood, but it has been demonstrated that nicotinamide can increase tumour perfusion (Horsman et al.,1988;
decrease 14C-misonidazole binding in tumours (Horsman et al.,1988;1989a), and increase tumour metabolic activity as measured by both biochemical analysis (Horsman et al.,1992),and 31P-NMR (Wood et al.,1991),all of which strongly suggest that nicotinamide works by improving tumour oxygenation at the time of irradiation.