| Medicinal products by therapeutic area | Interaction | Recommendations concerning co-administration |
| ANTI-HCV AGENTS |
| Grazoprevir 200 mg once daily (atazanavir 300 mg / ritonavir 100 mg once daily) | Atazanavir AUC ↑43% (↑30% ↑57%) Atazanavir Cmax ↑12% (↑1% ↑24%) Atazanavir Cmin ↑23% (↑13% ↑134%) Grazoprevir AUC: ↑958% (↑678% ↑1339%) Grazoprevir Cmax: ↑524% (↑342% ↑781%) Grazoprevir Cmin: ↑1064% (↑696% ↑1602%) Grazoprevir concentrations were greatly increased when co-administered with atazanavir/ritonavir. | Co-administration of Atazanavir and elbasvir/grazoprevir is contraindicated because of a significant increase in grazoprevir plasma concentrations and an associated potential increase in the risk of ALT elevations (see section 4.3). |
| Elbasvir 50 mg once daily (atazanavir 300 mg / ritonavir 100 mg once daily) | Atazanavir AUC ↑7% (↓2% ↑17%) Atazanavir Cmax ↑2% (↓4% ↑8%) Atazanavir Cmin ↑15% (↑2% ↑29%) Elbasvir AUC: ↑376% (↑307% ↑456%) Elbasvir Cmax: ↑315% (↑246% ↑397%) Elbasvir Cmin: ↑545% (↑451% ↑654%) Elbasvir concentrations were increased when co-administered with atazanavir/ritonavir. |
| Sofosbuvir 400 mg / velpatasvir 100 mg /voxilaprevir 100 mg single dose* (atazanavir 300 mg / ritonavir 100 mg once daily) | Sofosbuvir AUC: ↑40% (↑25% ↑57%) Sofosbuvir Cmax:↑29% (↑9% ↑52%) Velpatasvir AUC: ↑93% (↑58% ↑136%) Velpatasvir Cmax: ↑29% (↑7% ↑56%) Voxilaprevir AUC: ↑331% (↑276% ↑393%) Voxilaprevir Cmax: ↑342% (↑265% ↑435%) *Lack of pharmacokinetics interaction bounds 70-143% Effect on atazanavir and ritonavir exposure has not been studied. Expected: ↔ Atazanavir ↔ Ritonavir The mechanism of interaction between atazanavir/ritonavir and sofosbuvir/velpatasvir/voxilaprevir is inhibition of OATP1B, Pgp, and CYP3A. | Co-administration of atazanavir with voxilaprevir containing products is expected to increase the concentration of voxilaprevir. Co-administration of atazanavir with voxilaprevir-containing regimens is not recommended. |
| Glecaprevir 300 mg / pibrentasvir 120 mg once daily (atazanavir 300 mg / ritonavir 100 mg once daily*) | Glecaprevir AUC: ↑553% (↑424% ↑714%) Glecaprevir Cmax: ↑306% (↑215% ↑423%) Glecaprevir Cmin: ↑1330% (↑885% ↑1970%) Pibrentasvir AUC: ↑64% (↑48% ↑82%) Pibrentasvir Cmax: ↑29% (↑15% ↑45%) Pibrentasvir Cmin: ↑129% (↑95% ↑168%) * Effect of atazanavir and ritonavir on the first dose of glecaprevir and pibrentasvir is reported. | Co-administration of atazanavir with glecaprevir/pibrentasvir is contraindicated because of the potential increase in the risk of ALT elevations due to a significant increase in glecaprevir and pibrentasvir plasma concentrations (see section 4.3) |
| ANTIPLATELETS |
| Ticagrelor | The mechanism of the interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | Co-administration of atazanavir with ticagrelor is not recommended due to potential increase in the antiplatelet activity of ticagrelor. |
| Clopidogrel | The mechanism of the interaction is CYP3A4 inhibition by atazanavir and or/ritonavir. | Co-administration with clopidogrel is not recommended due to potential reduction of the antiplatelet activity of clopidogrel. |
| Prasugrel | The mechanism of the interaction is CYP3A4 inhibition by atazanavir and or/ritonavir. | No dose adjustment is needed when prasugrel is co-administered with atazanavir (with or without ritonavir). |
| ANTI-RETROVIRALS |
| Protease inhibitors: The co-administration of atazanavir/ritonavir and other protease inhibitors has not been studied but would be expected to increase exposure to other protease inhibitors. Therefore, such co-administration is not recommended. |
| Ritonavir 100 mg once daily (atazanavir 300 mg once daily) Studies conducted in HIV- infected patients. | Atazanavir AUC: ↑250% (↑144% ↑403%)* Atazanavir Cmax: ↑120% (↑56% ↑211%)* Atazanavir Cmin: ↑713% (↑359% ↑1339%)* *In a combined analysis, atazanavir 300 mg and ritonavir 100 mg (n=33) was compared to atazanavir 400 mg without ritonavir (n=28). The mechanism of interaction between atazanavir and ritonavir is CYP3A4 inhibition. | Ritonavir 100 mg once daily is used as a booster of atazanavir pharmacokinetics. |
| Indinavir | Indinavir is associated with indirect unconjugated hyperbilirubinaemia due to inhibition of UGT. | Co-administration of Atazanavir and indinavir is not recommended (see section 4.4). |
| Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) |
| Lamivudine 150 mg twice daily + zidovudine 300 mg twice daily (atazanavir 400 mg once daily) | No significant effect on lamivudine and zidovudine concentrations was observed. | Based on these data and because ritonavir is not expected to have a significant impact on the pharmacokinetics of NRTIs, the co-administration of these medicinal products and atazanavir is not expected to significantly alter the exposure of the co-administered medicinal products. |
| Abacavir | The co-administration of abacavir and atazanavir is not expected to significantly alter the exposure of abacavir. | |
| Didanosine (buffered tablets) 200 mg/stavudine 40 mg, both single dose (atazanavir 400 mg single dose) | Atazanavir, simultaneous administration with ddI+d4T (fasted) Atazanavir AUC ↓87% (↓92% ↓79%) Atazanavir Cmax ↓89% (↓94% ↓82%) Atazanavir Cmin ↓84% (↓90% ↓73%) Atazanavir, dosed 1 hour after ddI+d4T (fasted) Atazanavir AUC ↔3% (↓36% ↑67%) Atazanavir Cmax ↑12% (↓33% ↑18%) Atazanavir Cmin ↔3% (↓39% ↑73%) Atazanavir concentrations were greatly decreased when co-administered with didanosine (buffered tablets) and stavudine. The mechanism of interaction is a reduced solubility of atazanavir with increasing pH related to the presence of anti-acid agent in didanosine buffered tablets. No significant effect on didanosine and stavudine concentrations was observed. | Didanosine should be taken at the fasted state 2 hours after Atazanavir taken with food. The co-administration of stavudine with Atazanavir is not expected to significantly alter the exposure of stavudine. |
| Didanosine (enteric coated capsules) 400 mg single dose (atazanavir 300 mg once daily with ritonavir 100 mg once daily) | Didanosine (with food) Didanosine AUC ↓34% (↓41% ↓27%) Didanosine Cmax ↓38% (↓48% ↓26%) Didanosine Cmin ↑25% (↓8% ↑69%) No significant effect on atazanavir concentrations was observed when administered with enteric-coated didanosine, but administration with food decreased didanosine concentrations. |
| Tenofovir disoproxil fumarate 300 mg once daily (atazanavir 300 mg once daily with ritonavir 100 mg once daily) 300 mg tenofovir disoproxil fumarate is equivalent to 245 mg tenofovir disoproxil. Studies conducted in HIV- infected patients | Atazanavir AUC ↓22% (↓35% ↓6%) * Atazanavir Cmax ↓16% (↓30% ↔0%) * Atazanavir Cmin ↓23% (↓43% ↑2%) * * In a combined analysis from several clinical studies, atazanavir/ritonavir 300/100 mg co-administered with tenofovir disoproxil fumarate 300 mg (n=39) was compared to atazanavir/ritonavir 300/100 mg (n=33). The efficacy of atazanavir/ritonavir in combination with tenofovir disoproxil fumarate in treatment- experienced patients has been demonstrated in clinical study 045 and in treatment naive patients in clinical study 138 (see sections 4.8 and 5.1). The mechanism of interaction between atazanavir and tenofovir disoproxil fumarate is unknown. | When co-administered with tenofovir disoproxil fumarate, it is recommended that Atazanavir 300 mg be given with ritonavir 100 mg and tenofovir disoproxil fumarate 300 mg (all as a single dose with food). |
| Tenofovir disoproxil fumarate 300 mg once daily (atazanavir 300 mg once daily with ritonavir 100 mg once daily) 300 mg tenofovir disoproxil fumarate is equivalent to 245 mg tenofovir disoproxil. | Tenofovir disoproxil fumarate AUC ↑37% (↑30% ↑45%) Tenofovir disoproxil fumarate Cmax ↑34% (↑20% ↑51%) Tenofovir disoproxil fumarate Cmin ↑29% (↑21% ↑36%) | Patients should be closely monitored for tenofovir disoproxil fumarate -associated adverse reactions, including renal disorders. |
| Non-nucleoside reverse transcriptase inhibitors (NNRTIs) |
| Efavirenz 600 mg once daily (atazanavir 400 mg once daily with ritonavir 100 mg once daily) | Atazanavir (pm): all administered with food Atazanavir AUC ↔0% (↓9% ↑10%)* Atazanavir Cmax ↑17% (↑8% ↑27%)* Atazanavir Cmin ↓42% (↓51% ↓31%)* | Co-administration of efavirenz and Atazanavir is not recommended (see section 4.4) |
| Efavirenz 600 mg once daily (atazanavir 400 mg once daily with ritonavir 200 mg once daily) | Atazanavir (pm): all administered with food Atazanavir AUC ↔6% (↓10% ↑26%) */** Atazanavir Cmax ↔9% (↓5% ↑26%) */** Atazanavir Cmin ↔12% (↓16% ↑49%) */** * When compared to atazanavir 300 mg/ritonavir 100 mg once daily in the evening without efavirenz. This decrease in atazanavir Cmin, might negatively impact the efficacy of atazanavir. The mechanism of efavirenz/atazanavir interaction is CYP3A4 induction. ** Based on historical comparison. |
| Nevirapine 200 mg twice daily (atazanavir 400 mg once daily with ritonavir 100 mg once daily) Study conducted in HIV infected patients | Nevirapine AUC ↑26% (↑17% ↑36%) Nevirapine Cmax ↑21% (↑11% ↑32%) Nevirapine Cmin ↑35% (↑25% ↑47%) Atazanavir AUC ↓19% (↓35% ↑2%) * Atazanavir Cmax ↔2% (↓15% ↑24%) * Atazanavir Cmin ↓59% (↓73% ↓40%) * * When compared to atazanavir 300 mg and ritonavir 100 mg without nevirapine. This decrease in atazanavir Cmin, might negatively impact the efficacy of atazanavir. The mechanism of nevirapine/atazanavir interaction is CYP3A4 induction. | Co-administration of nevirapine and Atazanavir is not recommended (see section 4.4) |
| Integrase Inhibitors |
| Raltegravir 400 mg twice daily (atazanavir/ritonavir) | Raltegravir AUC ↑41% Raltegravir Cmax ↑24% Raltegravir C12hr ↑77% The mechanism is UGT1A1 inhibition. | No dose adjustment required for raltegravir. |
| ANTIBIOTICS |
| Clarithromycin 500 mg twice daily (atazanavir 400 mg once daily) | Clarithromycin AUC ↑94% (↑75% ↑116%) Clarithromycin Cmax ↑50% (↑32% ↑71%) Clarithromycin Cmin ↑160% (↑135% ↑188%) 14-OH clarithromycin 14-OH clarithromycin AUC ↓70% (↓74% ↓66%) 14-OH clarithromycin Cmax ↓72% (↓76% ↓67%) 14-OH clarithromycin Cmin ↓62% (↓66% ↓58%) Atazanavir AUC ↑28% (↑16% ↑43%) Atazanavir Cmax ↔6% (↓7% ↑20%) Atazanavir Cmin ↑91% (↑66% ↑121%) A dose reduction of clarithromycin may result in subtherapeutic concentrations of 14-OH clarithromycin. The mechanism of the clarithromycin/atazanavir interaction is CYP3A4 inhibition. | No recommendation regarding dose reduction can be made; therefore, caution should be exercised if Atazanavir is co- administered with clarithromycin. |
| ANTIFUNGALS |
| Ketoconazole 200 mg once daily (atazanavir 400 mg once daily) | No significant effect on atazanavir concentrations was observed. | Ketoconazole and itraconazole should be used cautiously with atazanavir/ritonavir, high doses of ketoconazole and itraconazole (>200 mg/day) are not recommended. |
| Itraconazole | Itraconazole, like ketoconazole, is a potent inhibitor as well as a substrate of CYP3A4. |
| | Based on data obtained with other boosted PIs and ketoconazole, where ketoconazole AUC showed a 3-fold increase, atazanavir/ritonavir is expected to increase ketoconazole or itraconazole concentrations. |
| Voriconazole 200 mg twice daily (atazanavir 300 mg/ritonavir 100 mg once daily) Subjects with at least one functional CYP2C19 allele. | Voriconazole AUC ↓33% (↓42% ↓22%) Voriconazole Cmax ↓10% (↓22% ↓4%) Voriconazole Cmin ↓39% (↓49% ↓28%) Atazanavir AUC ↓12% (↓18% ↓5%) Atazanavir Cmax ↓13% (↓20% ↓4%) Atazanavir Cmin ↓ 20 % (↓28 % ↓10%) Ritonavir AUC ↓12% (↓17% ↓7%) Ritonavir Cmax ↓9% (↓17% ↔0%) Ritonavir Cmin ↓25% (↓35% ↓14%) In the majority of patients with at least one functional CYP2C19 allele, a reduction in both voriconazole and atazanavir exposures are expected. | Co-administration of voriconazole and atazanavir with ritonavir is not recommended unless an assessment of the benefit/risk to the patient justifies the use of voriconazole (see section 4.4). At the time voriconazole treatment is required, a patient's CYP2C19 genotype should be performed if feasible. Therefore if the combination is unavoidable, the following recommendations are made according to the CYP2C19 status: - in patients with at least one functional CYP2C19 allele, close clinical monitoring for a loss of both voriconazole (clinical signs) and atazanavir (virologic response) efficacy is recommended. - in patients without a functional CYP2C19 allele, close clinical and laboratory monitoring of voriconazole-associated adverse events is recommended. If genotyping is not feasible, full monitoring of safety and efficacy should be performed. |
| Voriconazole 50 mg twice Daily (atazanavir 300 mg/ritonavir 100 mg once daily) Subjects without a functional CYP2C19 allele. | Voriconazole AUC ↑561% (↑451% ↑699%) Voriconazole Cmax ↑438% (↑355% ↑539%) Voriconazole Cmin ↑765% (↑571% ↑1,020%) Atazanavir AUC ↓20% (↓35% ↓3%) Atazanavir Cmax ↓19% (↓34% ↔0.2%) Atazanavir Cmin ↓31% (↓46 % ↓13%) Ritonavir AUC ↓11% (↓20% ↓1%) Ritonavir Cmax ↓11% (↓24% ↑4%) Ritonavir Cmin ↓19% (↓35% ↑1%) In a small number of patients without a functional CYP2C19 allele, significantly increased voriconazole exposures are expected. |
| Fluconazole 200 mg once daily (atazanavir 300 mg and ritonavir 100 mg once daily) | Atazanavir and fluconazole concentrations were not significantly modified when atazanavir/ritonavir was co-administered with fluconazole. | No dosage adjustments are needed for fluconazole and atazanavir. |
| ANTIMYCOBACTERIAL |
| Rifabutin 150 mg twice weekly (atazanavir 300 mg and ritonavir 100 mg once daily) | Rifabutin AUC ↑48% (↑19% ↑84%) ** Rifabutin Cmax ↑149% (↑103% ↑206%) ** Rifabutin Cmin ↑40% (↑5% ↑87%) ** 25-O-desacetyl-rifabutin AUC ↑990% (↑714% ↑1361%) ** 25-O-desacetyl-rifabutin Cmax ↑677% (↑513% ↑883%) ** 25-O-desacetyl-rifabutin Cmin ↑1045% (↑715% ↑1510%) ** ** When compared to rifabutin 150 mg once daily alone. Total rifabutin and 25-O-desacetyl-rifabutin AUC ↑119% (↑78% ↑169%). In previous studies, the pharmacokinetics of atazanavir was not altered by rifabutin. | When given with atazanavir, the recommended dose of rifabutin is 150 mg 3 times per week on set days (for example Monday-Wednesday-Friday). Increased monitoring for rifabutin-associated adverse reactions including neutropenia and uveitis is warranted due to an expected increase in exposure to rifabutin. Further dosage reduction of rifabutin to 150 mg twice weekly on set days is recommended for patients in whom the 150 mg dose 3 times per week is not tolerated. It should be kept in mind that the twice weekly dosage of 150 mg may not provide an optimal exposure to rifabutin thus leading to a risk of rifamycin resistance and a treatment failure. No dose adjustment is needed for atazanavir. |
| Rifampicin | Rifampicin is a strong CYP3A4 inducer and has been shown to cause a 72% decrease in atazanavir AUC which can result in virological failure and resistance development. During attempts to overcome the decreased exposure by increasing the dose of atazanavir or other protease inhibitors with ritonavir, a high frequency of liver reactions was seen. | The combination of rifampicin and Atazanavir is contraindicated (see section 4.3). |
| ANTIPSYCHOTICS |
| Quetiapine | Due to CYP3A4 inhibition by atazanavir, concentrations of quetiapine are expected to increase | Co-administration of quetiapine with Atazanavir is contraindicated as atazanavir may increase quetiapine-related toxicity. Increased plasma concentrations of quetiapine may lead to coma (see section 4.3) |
| Lurasidone | Atazanavir is expected to increase plasma levels of lurasidone due to CYP3A4 inhibition. | Co-administration of lurasidone with atazanavir is contra- indicated as this may increase lurasidone-related toxicity (see section 4.3). |
| ACID REDUCING AGENTS |
| H2-Receptor antagonists |
| Without Tenofovir |
| In HIV-infected patients with atazanavir/ritonavir at the recommended dose 300/100 mg once daily | For patients not taking tenofovir, if Atazanavir 300 mg/ritonavir 100 mg and H2-receptor antagonists are co-administered, a dose equivalent to famotidine 20 mg twice daily should not be exceeded. If a higher dose of an H2-receptor antagonist is required (e.g., famotidine 40 mg twice daily or equivalent) an increase of the atazanavir/ritonavir dose from 300/100 mg to 400/100 mg can be considered. |
| Famotidine 20 mg twice daily | Atazanavir AUC ↓18% (↓25% ↑1%) Atazanavir Cmax ↓20% (↓32% ↓7%) Atazanavir Cmin ↔1% (↓16% ↑18%) |
| Famotidine 40 mg twice daily | Atazanavir AUC ↓23% (↓32% ↓14%) Atazanavir Cmax ↓23% (↓33% ↓12%) Atazanavir Cmin ↓20% (↓31% ↓8%) |
| In Healthy volunteers with atazanavir/ritonavir at an increased dose of 400/100 mg once daily |
| Famotidine 40 mg twice daily | Atazanavir AUC ↔3% (↓14% ↑22%) Atazanavir Cmax ↔2% (↓13% ↑8%) Atazanavir Cmin ↓14% (↓32% ↑8%) |
| With tenofovir disoproxil fumarate 300 mg once daily (equivalent to 245 mg tenofovir disoproxil) |
| In HIV-infected patients with atazanavir/ritonavir at the recommended dose of 300/100 mg once daily | For patients who are taking tenofovir disoproxil fumarate, if atazanavir/ritonavir with both tenofovir disoproxil fumarate and an H2-receptor antagonist are co-administered, a dose increase of atazanavir to 400 mg with 100 mg of ritonavir is recommended. A dose equivalent to famotidine 40 mg twice daily should not be exceeded. |
| Famotidine 20 mg twice daily | Atazanavir AUC ↓21% (↓34% ↓4%) * Atazanavir Cmax ↓21% (↓36% ↓4%) * Atazanavir Cmin ↓19% (↓37% ↑5%) * |
| Famotidine 40 mg twice daily | Atazanavir AUC ↓24% (↓36% ↓11%)* Atazanavir Cmax ↓23% (↓36% ↓8%) * Atazanavir Cmin ↓25% (↓47% ↑7%) * |
| In HIV-infected patients with atazanavir/ritonavir at an increased dose of 400/100 mg once daily |
| Famotidine 20 mg twice daily | Atazanavir AUC ↑18% (↑6.5% ↑30%)* Atazanavir Cmax ↑18% (↑6.7% ↑31%)* Atazanavir Cmin ↑24 % (↑10% ↑39%)* |
| Famotidine 40 mg twice daily | Atazanavir AUC ↔2.3% (↓13% ↑10%)* Atazanavir Cmax ↔5% (↓17% ↑8.4%)* Atazanavir Cmin ↔1.3% (↓10% ↑15)* |
| | *When compared to atazanavir 300 mg once daily with ritonavir 100 mg once daily and tenofovir disoproxil fumarate 300 mg all as a single dose with food. When compared to atazanavir 300 mg with ritonavir 100 mg without tenofovir disoproxil fumarate, atazanavir concentrations are expected to be additionally decreased by about 20%. The mechanism of interaction is decreased solubility of atazanavir as intra-gastric pH increases with H2-blockers. |
| Proton pump inhibitors |
| Omeprazole 40 mg once daily (atazanavir 400 mg once daily with ritonavir 100 mg once daily) | Atazanavir (am): 2 hours after omeprazole Atazanavir AUC ↓61% (↓65% ↓55%) Atazanavir Cmax ↓66% (↓62% ↓49%) Atazanavir Cmin ↓65% (↓71% ↓59%) | Co-administration of Atazanavir with ritonavir and proton pump inhibitors is not recommended. If the combination is judged unavoidable, close clinical monitoring is recommended in combination with an increase in the dose of Atazanavir to 400 mg with 100 mg of ritonavir; doses of proton pump inhibitors comparable to omeprazole 20 mg should not be exceeded (see section 4.4). |
| Omeprazole 20 mg once daily (atazanavir 400 mg once daily with ritonavir 100 mg once daily) | Atazanavir (am): 1 hour after omeprazole Atazanavir AUC ↓30% (↓43% ↓14%) * Atazanavir Cmax ↓31% (↓42% ↓17%) * Atazanavir Cmin ↓31% (↓46% ↓12%) * *When compared to atazanavir 300 mg once daily with ritonavir 100 mg once daily. The decrease in AUC, Cmax, and Cmin was not mitigated when an increased dose of atazanavir/ritonavir (400/100 mg once daily) was temporally separated from omeprazole by 12 hours. Although not studied, similar results are expected with other proton pump inhibitors. This decrease in atazanavir exposure might negatively impact the efficacy of atazanavir. The mechanism of interaction is decreased solubility of atazanavir as intra-gastric pH increases with proton pump inhibitors. |
| Antacids |
| Antacids and medicinal products containing buffers | Reduced plasma concentrations of atazanavir may be the consequence of increased gastric pH if antacids, including buffered medicinal products, are administered with atazanavir. | Atazanavir should be administered 2 hours before or 1 hour after antacids or buffered medicinal products. |
| ALPHA 1-ADRENORECEPTOR ANTAGONIST |
| Alfuzosin | Potential for increased alfuzosin concentrations which can result in hypotension. The mechanism of interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | Co-administration of alfuzosin with atazanavir is contraindicated (see section 4.3) |
| ANTICOAGULANTS |
| Direct-acting oral anticoagulants (DOACs) |
| Apixaban Rivaroxaban | Potential for increased apixaban and rivaroxaban concentrations which can result in a higher risk of bleeding. The mechanism of interaction is inhibition of CYP3A4 and P-gp by atazanavir/ritonavir. Ritonavir is a strong inhibitor of both CYP3A4 and P-gp. Atazanavir is an inhibitor of CYP3A4. The potential inhibition of P-gp by atazanavir is unknown and cannot be excluded. | Co-administration of apixaban or rivaroxaban and atazanavir with ritonavir is not recommended. |
| Dabigatran | Potential for increased dabigatran concentrations which can result in a higher risk of bleeding. The mechanism of interaction is P-gp inhibition. Ritonavir is a strong P-gp inhibitor. Potential P-gp inhibition by atazanavir is unknown and cannot be excluded. | Co-administration of dabigatran and atazanavir with ritonavir is not recommended. |
| Edoxaban | Potential for increased edoxaban concentrations which can result in a higher risk of bleeding. The mechanism of interaction is P-gp inhibition by atazanavir/ritonavir. Ritonavir is a strong P-gp inhibitor. Potential P-gp inhibition by atazanavir is unknown and cannot be excluded. | Exercise caution when edoxaban is used with atazanavir. Please refer to edoxaban SmPC sections 4.2 and 4.5 for appropriate edoxaban dosage recommendations for co-administration with P-gp inhibitors. |
| Vitamin K antagonists |
| Warfarin | Co-administration with atazanavir has the potential to increase or decrease warfarin concentrations. | It is recommended that the International Normalised Ratio (INR) be monitored carefully during treatment with atazanavir, especially when commencing therapy. |
| ANTIEPILEPTICS |
| Carbamazepine | Atazanavir may increase plasma levels of carbamazepine due to CYP3A4 inhibition. Due to carbamazepine inducing effect, a reduction in atazanavir exposure cannot be ruled out. | Carbamazepine in combination with atazanavir (with or without ritonavir) is contraindicated due to the risk for loss of virologic response and development of resistance (see section 4.3). Close monitoring of the patient's virologic response should be excercised. |
| Phenytoin, phenobarbital | Ritonavir may decrease plasma levels of phenytoin and/or phenobarbital due to CYP2C9 and CYP2C19 induction. Due to phenytoin/phenobarbital inducing effect, a reduction in atazanavir exposure cannot be ruled out. | Phenobarbital and phenytoin in combination with atazanavir (with or without) ritonavir are contraindicated, due to the risk for loss of virologic response and development of resistance (see section 4.3). When atazanavir/ritonavir is co-administered with either phenytoin or phenobarbital, a dose adjustment of phenytoin or phenobarbital may be required. Close monitoring of patient's virologic response should be exercised. |
| Lamotrigine | Co-administration of lamotrigine and atazanavir/ritonavir may decrease lamotrigine plasma concentrations due to UGT1A4 induction. | Lamotrigine should be used with caution in combination with atazanavir/ritonavir. If necessary, monitor lamotrigine concentrations and adjust the dose accordingly. |
| ANTINEOPLASTICS AND IMMUNOSUPRESSANTS |
| Antineoplastics |
| Apalutamide | The mechanism of interaction is CYP3A4 induction by apalutamide and CYP3A4 inhibition by atazanavir/ritonavir. | Co-administration with atazanavir (with or without ritonavir) is contraindicated due to the potential for decreased atazanavir and ritonavir plasma concentration with subsequent loss of virologic response and possible resistance to the class of protease inhibitors (see section 4.3). In addition, serum concentrations of apalutamide may be increased when coadministered with atazanavir/ritonavir, resulting in the potential for serious adverse events including seizure. |
| Encorafenib | The mechanism of interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | Co-administration of encorafenib with atazanavir (with or without ritonavir) is contraindicated due to the potential for loss of virologic response, development of resistance, increase in encorafenib plasma concentration and subsequent risk of serious adverse events such as QT interval prolongation (see section 4.3). |
| Ivosidenib | The mechanism of interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | Co-administration of ivosidenib with atazanavir (with or without ritonavir) is contraindicated due to potential loss of virologic response, development of resistance,for increase in ivosidenib plasma concentration and subsequent risk of serious adverse events such as QT interval prolongation (see section 4.3). |
| Irinotecan | Atazanavir inhibits UGT and may interfere with the metabolism of irinotecan, resulting in increased irinotecan toxicities. | If atazanavir is co-administered with irinotecan, patients should be closely monitored for adverse events related to irinotecan. |
| Immunosuppressants |
| Cyclosporin Tacrolimus Sirolimus | Concentrations of these immunosuppressants may be increased when co-administered with atazanavir due to CYP3A4 inhibition. | More frequent therapeutic concentration monitoring of these medicinal products is recommended until plasma levels have been stabilised. |
| CARDIOVASCULAR AGENTS |
| Antiarrhythmics |
| Amiodarone, Systemic lidocaine, Quinidine | Concentrations of these antiarrhythmics may be increased when co-administered with atazanavir. The mechanism of amiodarone or systemic lidocaine/atazanavir interaction is CYP3A inhibition. Quinidine has a narrow therapeutic window and is contraindicated due to potential inhibition of CYP3A by atazanavir. | Caution is warranted and therapeutic concentration monitoring is recommended when available. The concomitant use of quinidine is contraindicated (see section 4.3). |
| Calcium channel blockers |
| Bepridil | Atazanavir should not be used in combination with medicinal products that are substrates of CYP3A4 and have a narrow therapeutic index. | Co-administration with bepridil is contraindicated (see section 4.3) |
| Diltiazem 180 mg once daily (atazanavir 400 mg once daily) | Diltiazem AUC ↑125% (↑109% ↑141%) Diltiazem Cmax ↑98% (↑78% ↑119%) Diltiazem Cmin ↑142% (↑114% ↑173%) Desacetyl-diltiazem AUC ↑165% (↑145% ↑187%) Desacetyl-diltiazem Cmax ↑172% (↑144% ↑203%) Desacetyl-diltiazem Cmin ↑121% (↑102% ↑142%) No significant effect on atazanavir concentrations was observed. There was an increase in the maximum PR interval compared to atazanavir alone. Co-administration of diltiazem and atazanavir/ritonavir has not been studied. The mechanism of diltiazem/atazanavir interaction is CYP3A4 inhibition. | An initial dose reduction of diltiazem by 50% is recommended, with subsequent titration as needed and ECG monitoring. |
| Verapamil | Serum concentrations of verapamil may be increased by atazanavir due to CYP3A4 inhibition. | Caution should be exercised when verapamil is co- administered with atazanavir. |
| CORTICOSTEROIDS |
| Dexamethasone and other corticosteroids (all routes of administration) | Co-administration with dexamethasone or other corticosteroids that induce CYP3A may result in loss of therapeutic effect of atazanavir and development of resistance to atazanavir and/or ritonavir. Alternative corticosteroids should be considered. The mechanism of interaction is CYP3A4 induction by dexamethasone and CYP3A4 inhibition by atazanavir and/or ritonavir. | Co-administration with corticosteroids (all routes of administration) that are metabolized by CYP3A, particularly for long-term use, may increase the risk for development of systemic corticosteroid effects including Cushing's syndrome and adrenal suppression. The potential benefit of treatment versus the risk of systemic corticosteroid effects should be considered. For co-administration of cutaneously administered corticosteroids sensitive to CYP3A inhibition, consult the Summary of Product Characteristics of the corticosteroid for condition or uses that augment its systemic absorption. |
| Fluticasone propionate intranasal 50 µg 4 times daily for 7 days (ritonavir 100 mg capsules twice daily) And Inhaled/Nasal Corticosteroids | The fluticasone propionate plasma levels increased significantly, whereas the intrinsic cortisol levels decreased by approximately 86% (90% confidence interval 82%-89%). Greater effects may be expected when fluticasone propionate is inhaled. Systemic corticosteroid effects including Cushing's syndrome and adrenal suppression have been reported in patients receiving ritonavir and inhaled or intranasally administered fluticasone propionate; this could also occur with other corticosteroids metabolised via the P450 3A pathway, e.g., budesonide. The effects of high fluticasone systemic exposure on ritonavir plasma levels are yet unknown. The mechanism of interaction is CYP3A4 inhibition. Concomitant use of atazanavir (with or without ritonavir) and other Inhaled/Nasal Corticosteroids is expected to produce the same effects. | Co-administration of atazanavir/ritonavir and these glucocorticoids metabolised by CYP3A4 is not recommended unless the potential benefit of treatment outweighs the risk of systemic corticosteroid effects (see section 4.4). A dose reduction of the glucocorticoid should be considered with close monitoring of local and systemic effects or a switch to a glucocorticoid, which is not a substrate for CYP3A4 (e.g., beclomethasone). Moreover, in case of withdrawal of glucocorticoids, progressive dose reduction may have to be performed over a longer period. Concomitant use of Inhaled/Nasal Corticosteroids and atazanavir (with or without ritonavir) may increase plasma concentrations of Inhaled/Nasal corticosteroids. Use with caution. Consider alternatives to Inhaled/Nasal Corticosteroids, particularly for long - term use. |
| ERECTILE DYSFUNCTION |
| PDE5 Inhibitors |
| Sildenafil, tadalafil, vardenafil | Sildenafil, tadalafil and vardenafil are metabolised by CYP3A4. Co- administration with atazanavir may result in increased concentrations of the PDE5 inhibitor and an increase in PDE5-associated adverse events, including hypotension, visual changes, and priapism. The mechanism of this interaction is CYP3A4 inhibition. | Patients should be warned about these possible side effects when using PDE5 inhibitors for erectile dysfunction with atazanavir (see section 4.4). Also see PULMONARY ARTERIAL HYPERTENSION in this table for further information regarding co- administration of atazanavir with sildenafil. |
| GONADOTROPIN -RELEASING HORMONE (GnRH) RECEPTOR ANTAGONISTS |
| Elagolix | The mechanism of interaction is anticipated increase in elagolix exposure in the presence of CYP3A4 inhibition by atazanavir and/or ritonavir. | Concomitant use of elagolix 200 mg twice daily with atazanavir (with or without ritonavir) for more than 1 month is not recommended due to the potential risk of adverse events such as bone loss and hepatic transaminase elevations. Limit concomitant use of elagolix 150 mg once daily with atazanavir (with or without ritonavir) to 6 months. |
| KINASE INHIBITORS |
| Fostamatinib | The mechanism of interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | Concomitant use of fostamatinib with atazanavir (with or without ritonavir) may increase the plasma concentration of R406, the active metabolite of fostamatinib. Monitor for toxicities of R406 exposure resulting in dose-related adverse events such as hepatotoxicity and neutropenia. Fostamatinib dose reduction may be required. |
| HERBAL PRODUCTS |
| St. John's wort (Hypericum perforatum) | Concomitant use of St. John's wort with atazanavir may be expected to result in significant reduction in plasma levels of atazanavir. This effect may be due to an induction of CYP3A4. There is a risk of loss of therapeutic effect and development of resistance (see section 4.3). | Co-administration of atazanavir with products containing St. John's Wort is contraindicated. |
| HORMONAL CONTRACEPTIVES |
| Ethinyloestradiol 25 μg + norgestimate (atazanavir 300 mg once daily with ritonavir 100 mg once daily) | Ethinyloestradiol AUC ↓19% (↓25% ↓13%) Ethinyloestradiol Cmax ↓16% (↓26% ↓5%) Ethinyloestradiol Cmin ↓37% (↓45% ↓29%) Norgestimate AUC ↑85% (↑67% ↑105%) Norgestimate Cmax ↑68% (↑51% ↑88%) Norgestimate Cmin ↑102% (↑77% ↑131%) While the concentration of ethinyloestradiol was increased with atazanavir given alone, due to both UGT and CYP3A4 inhibition by atazanavir, the net effect of atazanavir/ritonavir is a decrease in ethinyloestradiol levels because of the inducing effect of ritonavir. The increase in progestin exposure may lead to related side-effects (e.g. insulin resistance, dyslipidemia, acne and spotting), thus possibly affecting the compliance. | If an oral contraceptive is administered with atazanavir/ritonavir, it is recommended that the oral contraceptive contain at least 30 μg of ethinyloestradiol and that the patient be reminded of strict compliance with this contraceptive dosing regimen. Co-administration of atazanavir/ritonavir with other hormonal contraceptives or oral contraceptives containing progestogens other than norgestimate has not been studied, and therefore should be avoided. An alternate reliable method of contraception is recommended. |
| Ethinyloestradiol 35 µg + norethindrone (atazanavir 400 mg once daily) | Ethinyloestradiol AUC ↑48% (↑31% ↑68%) Ethinyloestradiol Cmax ↑15% (↓1% ↑32%) Ethinyloestradiol Cmin ↑91% (↑57% ↑133%) Norethindrone AUC ↑110% (↑68% ↑162%) Norethindrone Cmax ↑67% (↑42% ↑196%) Norethindrone Cmin ↑262% (↑157% ↑409%) The increase in progestin exposure may lead to related side-effects (e.g. insulin resistance, dyslipidemia, acne and spotting), thus possibly affecting the compliance. | |
| LIPID MODIFYING AGENTS |
| HMG-CoA reductase inhibitors |
| Simvastatin Lovastatin | Simvastatin and lovastatin are highly dependent on CYP3A4 for their metabolism and co-administration with atazanavir may result in increased concentrations. | Co-administration of simvastatin or lovastatin with atazanavir is contraindicated due to an increased risk of myopathy including rhabdomyolysis (see section 4.3). |
| Atorvastatin | The risk of myopathy including rhabdomyolysis may also be increased with atorvastatin, which is also metabolised by CYP3A4. | Co-administration of atorvastatin with atazanavir is not recommended. If the use of atorvastatin is considered strictly necessary, the lowest possible dose of atorvastatin should be administered with careful safety monitoring (see section 4.4). |
| Pravastatin Fluvastatin | Although not studied, there is a potential for an increase in pravastatin or fluvastatin exposure when co- administered with protease inhibitors. Pravastatin is not metabolised by CYP3A4. Fluvastatin is partially metabolised by CYP2C9. | Caution should be exercised. |
| Other lipid-modifying agents |
| Lomitapide | Lomitapide is highly dependent on CYP3A4 for metabolism and co-administration with atazanavir with ritonavir may result in increased concentrations. | Co-administration of lomitapide and atazanavir with ritonavir is contraindicated due to a potential risk of markedly increased transaminase levels and hepatotoxicity (see section 4.3). |
| INHALED BETA AGONISTS |
| Salmeterol | Co-administration with atazanavir may result in increased concentrations of salmeterol and an increase in salmeterol-associated adverse events. The mechanism of interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | Co-administration of salmeterol with atazanavir is not recommended (see section 4.4). |
| OPIOIDS |
| Buprenorphine, once daily, stable maintenance dose (atazanavir 300 mg once daily with ritonavir 100 mg once daily) | Buprenorphine AUC ↑67% Buprenorphine Cmax ↑37% Buprenorphine Cmin ↑69% Norbuprenorphine AUC ↑105% Norbuprenorphine Cmax ↑61% Norbuprenorphine Cmin ↑101% The mechanism of interaction is CYP3A4 and UGT1A1 inhibition. Concentrations of atazanavir (when given with ritonavir) were not significantly affected. | Co-administration with Atazanavir with ritonavir warrants clinical monitoring for sedation and cognitive effects. A dose reduction of buprenorphine may be considered. |
| Methadone, stable maintenance dose (atazanavir 400 mg once daily) | No significant effect on methadone concentrations was observed. Given that low dose ritonavir (100 mg twice daily) has been shown to have no significant effect on methadone concentrations, no interaction is expected if methadone is co- administered with atazanavir, based on these data. | No dosage adjustment is necessary if methadone is co- administered with Atazanavir. |
| PULMONARY ARTERIAL HYPERTENSION |
| PDE5 Inhibitors |
| Sildenafil | Co-administration with atazanavir may result in increased concentrations of the PDE5 inhibitor and an increase in PDE5-inhibitor-associated adverse events. The mechanism of interaction is CYP3A4 inhibition by atazanavir and/or ritonavir. | A safe and effective dose in combination with Atazanavir has not been established for sildenafil when used to treat pulmonary arterial hypertension. Sildenafil, when used for the treatment of pulmonary arterial hypertension, is contraindicated (see section 4.3). |
| SEDATIVES |
| Benzodiazepines |
| Midazolam Triazolam | Midazolam and triazolam are extensively metabolised by CYP3A4. Co-administration with atazanavir may cause a large increase in the concentration of these benzodiazepines. No drug interaction study has been performed for the co- administration of atazanavir with benzodiazepines. Based on data for other CYP3A4 inhibitors, plasma concentrations of midazolam are expected to be significantly higher when midazolam is given orally. Data from concomitant use of parenteral midazolam with other protease inhibitors suggest a possible 3-4 fold increase in midazolam plasma levels. | Co-administration of Atazanavir with triazolam or orally administered midazolam is contraindicated (see section 4.3), whereas caution should be used with co-administration of Atazanavir and parenteral midazolam. If Atazanavir is co-administered with parenteral midazolam, it should be done in an intensive care unit (ICU) or similar setting which ensures close clinical monitoring and appropriate medical management in case of respiratory depression and/or prolonged sedation. Dosage adjustment for midazolam should be considered, especially if more than a single dose of midazolam is administered. |