Coadministration of tenofovir-DF and raltegravir (400 mg twice daily) increased raltegravir AUC by 49%, Cmax by 64% and Cmin by 3%. Tenofovir AUC decreased by 10%, Cmax by 33% and Cmin by 13%. These findings can be extended to raltegravir 1,200 mg once daily. No dose adjustment required for raltegravir (400 mg twice daily and 1,200 mg once daily) or tenofovir disoproxil fumarate. 
Isentress 600 mg Summary of Product Characteristics, Merck Sharp & Dohme Ltd, September 2021.

Coadministration of tenofovir-DF (300 mg once daily) and raltegravir (400 mg twice daily) increased raltegravir Cmax by 64%, AUC by 49% and Cmin by 3% (n=9). In drug interaction studies performed using raltegravir film-coated tablets 400 mg twice daily dose, raltegravir did not have a clinically meaningful effect on the pharmacokinetics of tenofovir (tenofovir Cmax, AUC and C24 decreased by 23%, 10% and 13%; n=9). No dose adjustment is required when raltegravir 400 mg twice daily or 1200 mg once daily is coadministered.
Isentress Prescribing Information, Merck & Co Inc, August 2021.

Coadministration of raltegravir (400 mg twice daily for 4 days) and tenofovir-DF (300 mg once daily for 7 days) alone and in combination for 4 days was studied in HIV- subjects. Pharmacokinetic profiles were also determined in HIV+ patients given raltegravir monotherapy alone or in combination with tenofovir-DF/lamivudine. In healthy volunteers raltegravir AUC and Cmax were modestly increased in the presence of tenofovir-DF (49% and 64%, respectively), while there was no effect of tenofovir-DF on raltegravir Cmin (3% increase). However, there was a modest increase of 42% in Cmin in HIV-infected patients. Raltegravir only had a small effect on tenofovir-DF AUC (10% decrease), Cmax (23% decrease) and Cmin (13% decrease). The authors conclude that coadministration of raltegravir and tenofovir-DF does not change the pharmacokinetics of either drug to a clinically meaningful degree and consequently may be coadministered without dose adjustments.
Lack of a significant interaction between raltegravir and tenofovir. Wenning LA, Friedman EJ, Kost JT, et al. Antimicrob Agents Chemother, 2008, 52(9): 3253-3258.