Tolerability of enteric-coated didanosine capsules compared with didanosine tablets in adults with HIV infection

Background: A new enteric-coated (EC) didanosine (ddI) formulation (Videx E C; Bristol-Myers Squibb, Princeton, NJ, U.S.A.) may be better tolerated tha n the tablet form because it lacks the buffer component thought to be respo nsible for diarrhea and other gastrointestinal (GI) side effects. Objective: To evaluate the frequency and magnitude of GI side effects (naus ea, bloating, GI upset, diarrhea, abdominal cramps, gas [flatus]) before an d after switching the formulation of ddI, in study subjects who were experi encing one or more GI symptom(s) of at least moderate severity. Methods: A 6-week open label crossover study of current didanosine tablet u sers comparing daily symptom scores (7 point scale, 0 = absent to 6 = very severe) during weeks 1 to 2 (on tablets) to weeks 4 and 6 (on EC capsules). Formulation palatability and preference, lifestyle effects, and use of ant idiarrheals or other medications for symptom relief were also assessed. Results: GI symptom scores (7-day means) on tablets were diarrhea 2.11, gas 2.00, bloating 1.23, abdominal cramps 0.74, GI upset 0.69, nausea 0.66. Af ter switching to EC (week 4 and week 6), mean scores decreased for diarrhea (mean scores 0.99 week 4, 0.79 week 6), gas (0.95, 0.79), bloating (0.49, 0.32), abdominal cramps (0.21, 0.05), GI upset (0.16, 0.14), and nausea (0. 32, 0.22). Severity of all GI symptoms was significantly reduced after 4 we eks on EC capsules (p < .01 by paired t-test). Negative impact of side effe cts on routine activities was significantly reduced (41% on tablet vs. 7% o n EC; p < .01). All 42 study subjects preferred the EC form. Conclusions: According to patients' diary scores, switching to ddI in EC fo rm significantly reduces nausea, bloating, GI upset, diarrhea, abdominal cr amps, and gas for individuals who experienced GI side effects while taking the buffered tablet form, The striking tolerability advantages appear to su pport routine switching to EC for such patients and may suggest that widesp read preferential selection of the EC form is appropriate to enhance didano sine tolerability and promote treatment adherence.