RALTEGRAVIR Drug Interactions: What You Need to Know

INTERACTIONS

• Coadministration of ISENTRESS or ISENTRESS HD and other drugs may alter the plasma concentration of raltegravir. The potential for drug-drug interactions must be considered prior to and during therapy ( 7 ).
• Coadministration of ISENTRESS or ISENTRESS HD with drugs that are strong inducers of UGT1A1, such as rifampin, may result in reduced plasma concentrations of raltegravir ( 2.1 , 7.1 ).

7.1 Effect of Other Agents on the Pharmacokinetics of Raltegravir Raltegravir is not a substrate of cytochrome P450 (CYP) enzymes. Based on in vivo and in vitro studies, raltegravir is eliminated mainly by metabolism via a UGT1A1-mediated glucuronidation pathway. Coadministration of ISENTRESS with drugs that inhibit UGT1A1 may increase plasma levels of raltegravir and coadministration of ISENTRESS with drugs that induce UGT1A1, such as rifampin, may reduce plasma levels of raltegravir (see Table 11 ). Selected drug interactions are presented in Table 11 <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> . In some cases, recommendations differ for ISENTRESS versus ISENTRESS HD.

Table

11: Selected Drug Interactions in Adults Concomitant Drug Class: Drug Name Effect on Concentration of Raltegravir Clinical Comment for ISENTRESS Clinical Comment for ISENTRESS HD Metal-Containing Antacids Aluminum and/or magnesium-containing antacids ↓ Coadministration or staggered administration is not recommended. Calcium carbonate antacid ↓ No dose adjustment Co-administration is not recommended Other Agents Rifampin ↓ The recommended dosage is 800 mg twice daily during coadministration with rifampin. There are no data to guide co-administration of ISENTRESS with rifampin in patients below 18 years of age [see Dosage and Administration (2.1) ]. Coadministration is not recommended. Tipranavir/ritonavir No dose adjustment Coadministration is not recommended Etravirine ↓ No dose adjustment Coadministration is not recommended. Strong inducers of drug metabolizing enzymes not mentioned above e.g., Carbamazepine Phenobarbital Phenytoin ↓↔ The impact of other strong inducers of drug metabolizing enzymes on raltegravir is unknown. Coadministration is not recommended.

7.2 Drugs without Clinically Significant Interactions with ISENTRESS or ISENTRESS HD ISENTRESS In drug interaction studies performed using ISENTRESS film-coated tablets 400 mg twice daily dose, raltegravir did not have a clinically meaningful effect on the pharmacokinetics of the following: ethinyl estradiol/norgestimate, methadone, midazolam, lamivudine, tenofovir disoproxil fumarate, etravirine, darunavir/ritonavir, or boceprevir. Moreover, atazanavir, atazanavir/ritonavir, boceprevir, calcium carbonate antacids, darunavir/ritonavir, efavirenz, etravirine, omeprazole, or tipranavir/ritonavir did not have a clinically meaningful effect on the pharmacokinetics of 400 mg twice daily raltegravir. No dose adjustment is required when ISENTRESS 400 mg twice daily is coadministered with these drugs. There is no predicted pharmacokinetic drug interaction between ISENTRESS and tenofovir alafenamide.

Isentress Hd

In drug interaction studies, efavirenz did not have a clinically meaningful effect on the pharmacokinetics of ISENTRESS HD 1200 mg (2 × 600 mg) once daily. No dose adjustment is recommended when ISENTRESS HD 1200 mg once daily is coadministered with atazanavir, atazanavir/ritonavir, hormonal contraceptives, methadone, lamivudine, tenofovir disoproxil fumarate, darunavir/ritonavir, boceprevir, efavirenz and omeprazole. There is no predicted pharmacokinetic drug interaction between ISENTRESS HD and tenofovir alafenamide.

None None ( 4) .

AND PRECAUTIONS

• Severe, potentially life-threatening and fatal skin reactions have been reported. This includes cases of Stevens-Johnson syndrome, hypersensitivity reaction and toxic epidermal necrolysis. Immediately discontinue treatment with ISENTRESS or ISENTRESS HD and other suspect agents if severe hypersensitivity, severe rash, or rash with systemic symptoms or liver aminotransferase elevations develops and monitor clinical status, including liver aminotransferases closely ( 5.1 ).
• Monitor for Immune Reconstitution Syndrome ( 5.2 ).
• Inform patients with phenylketonuria that the 100 mg and 25 mg chewable tablets contain phenylalanine ( 5.3 ).

5.1 Severe Skin and Hypersensitivity Reactions Severe, potentially life-threatening, and fatal skin reactions have been reported. These include cases of Stevens-Johnson syndrome and toxic epidermal necrolysis. Hypersensitivity reactions have also been reported and were characterized by rash, constitutional findings, and sometimes, organ dysfunction, including hepatic failure. Discontinue ISENTRESS or ISENTRESS HD and other suspect agents immediately if signs or symptoms of severe skin reactions or hypersensitivity reactions develop (including, but not limited to, severe rash or rash accompanied by fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, facial edema, hepatitis, eosinophilia, angioedema). Clinical status including liver aminotransferases should be monitored and appropriate therapy initiated. Delay in stopping ISENTRESS or ISENTRESS HD treatment or other suspect agents after the onset of severe rash may result in a life-threatening reaction.

5.2 Immune Reconstitution Syndrome Immune reconstitution syndrome has been reported in patients treated with combination antiretroviral therapy, including ISENTRESS. During the initial phase of combination antiretroviral treatment, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci pneumonia, tuberculosis), which may necessitate further evaluation and treatment. Autoimmune disorders (such as Graves&apos; disease, polymyositis, and Guillain-Barré syndrome) have also been reported to occur in the setting of immune reconstitution; however, the time to onset is more variable, and can occur many months after initiation of treatment.

5.3 Phenylketonurics ISENTRESS Chewable Tablets contain phenylalanine, a component of aspartame.

Each

25 mg ISENTRESS Chewable Tablet contains approximately 0.05 mg phenylalanine.

Each

100 mg ISENTRESS Chewable Tablet contains approximately 0.10 mg phenylalanine. Phenylalanine can be harmful to patients with phenylketonuria.