Nicotinamide inhibits HIV-1 in both acute and chronic in vitro infection.

HIV-1 infected patients can manifest a number of poorly understood conditions including dermatitis, dementia, and diarrhea. These conditions are in some ways suggestive of pellagra, the syndrome associated with niacin depletion. We demonstrate here that nicotinamide, the amide form of niacin, inhibits HIV-1 infection in cell culture. Neither nicotinic acid which is the alternative form of niacin, nor thiamine (another B complex vitamin), shows a similar degree of inhibition in tissue culture. This inhibition occurs in both primary cells and in established cell lines. In vitro models of acute and chronic HIV infection are demonstrated here to be inhibited by nicotinamide in a dose dependent manner when added in millimolar concentrations.