Coadministration of didanosine (200 mg twice daily if 60 kg or above, 125 mg twice daily if <60 kg) and tipranavir/ritonavir (250/200 mg twice daily) decreased didanosine Cmax and AUC by 43% and 33%. When the same weight related doses were administered with tipranavir/ritonavir (750/100 mg twice daily) didanosine Cmax decreased by 24% and there was no change in AUC. The clinical relevance of this reduction in didanosine concentrations has not been established. Dosing of enteric-coated didanosine and tipranavir soft capsules, co-administered with low dose ritonavir, should be separated by at least 2 hours to avoid formulation incompatibility.
Aptivus Summary of Product Characteristics, Boehringer Ingelheim Ltd, July 2020.

Coadministration of tipranavir/ritonavir (500/100 mg twice daily) with a single dose of didanosine (400 mg) to 5 subjects increased tipranavir Cmax and AUC by 32% and 8% respectively, but decreased Cmin by 34%. Didanosine Cmax and AUC were decreased by 20% and 10% respectively, and Cmin increased by 17%. Coadministration of didanosine (200 mg twice daily if 60 kg or above, 125 mg twice daily if <60 kg) and tipranavir/ritonavir (250/200 mg twice daily) to 10 HIV+ subjects resulted in a 43% decrease in didanosine Cmax and a 33% decrease in AUC. When the same weight related doses were administered with tipranavir/ritonavir (750/100 mg twice daily) to 8 HIV+ subjects, didanosine Cmax decreased by 24% and AUC decreased by 3%. When the same weight related doses were administered with tipranavir/ritonavir (1250/100 mg twice daily) to 9 HIV+ subjects, didanosine Cmax decreased by 23% and AUC decreased by 13%. Clinical relevance of reduction in didanosine levels not established. For optimal absorption, didanosine should be separated from tipranavir/ritonavir dosing by at least 2 h.
Aptivus Prescribing Information, Boehringer Ingelheim, June 2020.

When enteric coated ddI and tipranavir/ritonavir (500/100 mg or 750/200 mg bd) were coadministered to 23 HIV- subjects, no change in the pharmacokinetic profile of ddI was observed. Tipranavir AUC was unchanged, Cmax increased by 32%, and Cmin decreased by 34%. Administration of enteric ddI and tipranavir/ritonavir should be separated by 4 h.
Standard doses of efavirenz, zidovudine, tenofovir and didanosine may be given with tipranavir/ritonavir. Roszko PJ, Curry K, Brazina B, et al. 2nd International AIDS Society Conference on HIV Pathogenesis and Treatment, Paris, July 2003, abstract 865.

The addition of tipranavir/ritonavir (1250/100 mg, n=9; 750/100 mg, n=8; 250/100 mg, n=10) was studied in HIV+ subjects on stable HAART regimens containing didanosine. No clinically significant changes in didanosine AUC were observed.
Pharmacokinetic drug interaction screen of three doses of tipranavir/ritonavir in HIV-infected patients on stable highly active antiretroviral therapy. Goebel FD, Sabo JP, MacGregor TR, et al. HIV DART, Naples (Florida), December 2002.

Coadministration of ddI (200 mg bd, n=4) and tipranavir (900, 1200 or 1500 mg, three times daily) resulted in a decrease in ddI AUC from 1280±1000 to 692±321 ng/ml.h.
The pharmacokinetics of nucleoside reverse transcriptase inhibitors when coadministered with the HIV protease inhibitor tipranavir in HIV-1 infected patients. Phillips H, Borin MT, Hopkins NK, et al. 7th Conference on Retroviruses and Opportunistic Infections, San Francisco, February 2000, abstract 81.