The power of simplicity.

Many years of use have confirmed didanosine to be among the most potent of nucleoside analogues. Didanosine's potency has been demonstrated in mono-, dual- and triple-therapy. Didanosine is currently available as a once-daily, enteric-coated tablet, which has reduced gastrointestinal side effects compared with the older, buffered formulation. Once-daily dosing and good tolerability improve adherence, and hence also virological control. The prevalence of phenotypic nucleoside resistance to didanosine is low compared with that to zidovudine, lamivudine and abacavir. At least 6 nucleoside analogue mutations are needed in order for the virus to lose sensitivity to didanosine. Didanosine is effective in patients failing lamivudine therapy who have the M184V mutation. Enteric-coated didanosine is also an important component of early therapy, due to its potency and ease of administration.