Triazolam is contraindicated with ritonavir as coadministration increases plasma concentrations of triazolam, thereby increasing the risk of extreme sedation and respiratory depression. Coadministration of triazolam (0.125 mg single dose) and ritonavir (200 mg four doses) increased triazolam AUC by more than 20-fold and Cmin by 87%.
Norvir Summary of Product Characteristics, AbbVie Ltd, September 2016.

Triazolam is contraindicated with ritonavir due to potential for serious and/or life threatening reactions such as prolonged or increased sedation or respiratory depression.
Norvir Prescribing Information, AbbVie Inc, December 2016.

The effect of ritonavir (200 mg 12 hourly, 4 doses) on triazolam (0.125 mg) was evaluated in six healthy volunteers. Ritonavir produced a large and highly significant increase in triazolam Cmax, an increase in AUC, prolongation of elimination half-life and decreased clearance to less than 4% when compared to control values. The increased plasma concentration of triazolam were accompanied by enhanced pharmacodynamic activity of triazolam. Therefore, initial exposure to ritonavir in triazolam-treated patients will in fact increase the potential for excessive sedative effects and cautions regarding possible hazards of this combination appear to be warranted.
Differential impairment of triazolam and zolpidem clearance by ritonavir. Greenblatt DJ, von Moltke LL, Harmatz JS, et al. J Acquir Immune Defic Syndr, 2000, 24:129–36.