загрызть ( вн. )
bite* to death ( d. ); ( перен. ) разг. worry to death ( d. ); worry the life out (of)
тоска его загрызла — he is consumed with melancholy / misery, he is melancholic, he is sick a heart
совесть его загрызла — he is consumed by remorse, he is con science-stricken