darr; 90)
Methadone Stable maintenance 35–100 mg daily 600 mg qd × 14–21 days 11 ↓ 45
(↓ 25 to
↓ 59) ↓ 52
(↓ 33 to
↓ 66) NA
Bupropion 150 mg single dose
(sustained-release) 600 mg qd × 14 days 13 ↓ 34
(↓21 to ↓47) ↓ 55
(↓48 to ↓62) NA
Hydroxybupropion ↑ 50
(↑ 20 to
↑ 80) ↔ NA
Sertraline 50 mg qd × 14 days 600 mg qd × 14 days 13 ↓ 29
(↓ 15 to
↓ 40) ↓ 39
(↓ 27 to
↓ 50) ↓ 46
(↓ 31 to
↓ 58)
400 mg po q12h × 1 day then 200 mg po q12h × 8 days 400 mg qd × 9 days NA ↓ 61à ↓ 7720 NA
Voriconazole 300 mg po q12h days 2–7 300 mg qd × 7 days NA ↓ 36è
(↓ 21 to
↓ 49) ↓ 5521
(↓ 45 to
↓ 62) NA
400 mg po q12h days 2–7 300 mg qd × 7 days NA ↑ 2321
(↓ 1 to
↑ 53 ↓ 721
(↓ 23 to
↑ 13) NA
12
13
14
15
16
17
18
19
20
21
Emtricitabine and Tenofovir Disoproxil Fumarate: The steady-state pharmacokinetics of emtricitabine and tenofovir were unaffected when emtricitabine and tenofovir DF were administered together versus each agent dosed alone.
In vitro and clinical pharmacokinetic drug-drug interaction studies have shown that the potential for CYP mediated interactions involving emtricitabine and tenofovir with other medicinal products is low.
Emtricitabine and tenofovir are primarily excreted by the kidneys by a combination of glomerular filtration and active tubular secretion. No drug-drug interactions due to competition for renal excretion have been observed; however, coadministration of emtricitabine and tenofovir DF with drugs that are eliminated by active tubular secretion may increase concentrations of emtricitabine, tenofovir, and/or the coadministered drug.
Drugs that decrease renal function may increase concentrations of emtricitabine and/or tenofovir.
No clinically significant drug interactions have been observed between emtricitabine and famciclovir, indinavir, stavudine, tenofovir DF and zidovudine. Similarly, no clinically significant drug interactions have been observed between tenofovir DF and abacavir, efavirenz, emtricitabine, entecavir, indinavir, lamivudine, lopinavir/ritonavir, methadone, nelfinavir, oral contraceptives, ribavirin, saquinavir/ritonavir or tacrolimus in trials conducted in healthy volunteers.
Following multiple dosing to HIV-negative subjects receiving either chronic methadone maintenance therapy, oral contraceptives, or single doses of ribavirin, steady-state tenofovir pharmacokinetics were similar to those observed in previous trials, indicating a lack of clinically significant drug interactions between these agents and tenofovir DF. The effects of coadministered drugs on the Cmax, AUC, and Cmin of tenofovir are shown in Table 7. The effects of coadministration of tenofovir DF on Cmax, AUC, and Cmin of coadministered drugs are shown in Table 8 and Table 9.
Table 7 Drug Interactions: Changes in Pharmacokinetic Parameters for Tenofovir in the Presence of the Coadministered Drug*,† Coadministered Drug Dose of Coadministered Drug (mg) N Mean % Change of Tenofovir Pharmacokinetic Parameters‡
(90% CI)
Cmax AUC Cmin
Atazanavir&s
