Acyclovir

Changes in pharmacokinetics of tizanidine when administered with ciprofloxacin resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [See Contraindications (4) and Clinical Pharmacology ( 12.3 ) ] 7.3 CYP1A2 Inhibitors other than Fluvoxamine and Ciprofloxacin Because of potential drug interactions, concomitant use of tizanidine hydrochloride with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than strong CYP1A2 inhibitors (which are contraindicated), antiarrythmics (amiodarone, mexiletine, propafenone, and verapamil), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided.

Changes in pharmacokinetics of tizanidine when administered with ciprofloxacin resulted in significantly decreased blood pressure, increased drowsiness, and increased psychomotor impairment [see Contraindications (4) and Clinical Pharmacology (12.3)] 7.3 CYP1A2 Inhibitors other than Fluvoxamine and Ciprofloxacin Because of potential drug interactions, concomitant use of tizanidine with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than strong CYP1A2 inhibitors (which are contraindicated), antiarrythmics (amiodarone, mexiletine, propafenone, and verapamil), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided.

7.3 CYP1A2 Inhibitors other than Fluvoxamine and Ciprofloxacin Because of potential drug interactions, concomitant use of tizanidine with other CYP1A2 inhibitors, such as zileuton, fluoroquinolones other than strong CYP1A2 inhibitors (which are contraindicated), antiarrhythmics (amiodarone, mexiletine, propafenone, and verapamil), cimetidine, famotidine, oral contraceptives, acyclovir, and ticlopidine) should be avoided.

Concomitant use should be avoided due to additive nephrotoxicity and renal impairment risk.

Acyclovir may interfere with the effectiveness of IMLYGIC (talimogene laherparepvec). IMLYGIC is sensitive to acyclovir.

CYP1A2 inhibitor that increases warfarin effect and INR; requires close INR monitoring

CYP1A2 inhibitor that increases warfarin effect and INR; requires closer INR monitoring.

Eliminated by active tubular secretion; coadministration may increase tenofovir and acyclovir concentrations, increasing adverse reaction risk.

Coadministration may increase concentrations of acyclovir and renally eliminated drugs, increasing risk of adverse reactions.

Eliminated by active tubular secretion; may increase concentrations of acyclovir and/or emtricitabine/tenofovir.

Coadministration may increase concentrations of tenofovir and/or acyclovir due to competition for active tubular secretion in the kidneys.

Acyclovir is eliminated by active tubular secretion; coadministration may increase concentrations of acyclovir and emtricitabine/tenofovir, increasing risk of adverse reactions.

Coadministration may increase concentrations of FTC, tenofovir, and acyclovir due to competition for active tubular secretion.

Coadministration may increase concentrations of acyclovir and/or tenofovir due to competition for renal tubular secretion. Monitor for tenofovir toxicity.

Coadministration may increase serum concentrations of emtricitabine, tenofovir, and/or acyclovir due to competition for renal tubular secretion.

Coadministration may increase serum concentrations of FTC, tenofovir, and/or acyclovir due to competition for active tubular secretion.

Coadministration may increase concentrations of FTC, tenofovir, and/or acyclovir due to competition for active tubular secretion in kidneys.

May increase serum tenofovir concentrations and/or increase concentrations of other renally eliminated drugs.

Acyclovir Clinical Impact: The concomitant use of acyclovir may increase the plasma concentrations of meperidine and its metabolite, normeperidine. Intervention: If concomitant use of acyclovir and Meperidine Hydrochloride Injection is necessary, monitor patients for respiratory depression and sedation at frequent intervals.

( 5.2 , 7.8 ) Acyclovir, Valacyclovir, Ganciclovir, Valganciclovir, and Other Drugs that Undergo Renal Tubular Secretion: May increase concentrations of mycophenolic acid glucuronide (MPAG) and coadministered drug; monitor blood cell counts. 7.9 Acyclovir (Valacyclovir), Ganciclovir (Valganciclovir), and Other Drugs That Undergo Renal Tubular Secretion The coadministration of MMF and acyclovir or ganciclovir may increase plasma concentrations of mycophenolic acid glucuronide (MPAG) and acyclovir/valacyclovir/ganciclovir/valganciclovir as their coexistence competes for tubular secretion. Both acyclovir/valacyclovir/ganciclovir/valganciclovir and MPAG concentrations will be also increased in the presence of renal impairment.

Drug Interactions with Mycophenolate Mofetil that Affect Other Drugs Drugs that Undergo Renal Tubular Secretion Clinical Impact When concomitantly used with mycophenolate mofetil, its metabolite MPAG, may compete with drugs eliminated by renal tubular secretion which may increase plasma concentrations and/or adverse reactions associated with these drugs Prevention or Management Monitor for drug-related adverse reactions in patients with renal impairment Examples Acyclovir, ganciclovir, probenecid, valacyclovir, valganciclovir Combination Oral Contraceptives Clinical Impact Concomitant use with mycophenolate mofetil decreased the systemic exposure to levonorgestrel, but did not affect the systemic exposure to ethinylestradiol [see Clinical Pharmacology ( 12.3 )], which may result in reduced combination oral contraceptive effectiveness.

Coadministration increases acyclovir half-life and area under the concentration-time curve, with reduced urinary excretion and renal clearance.

Coadministration may increase tenofovir concentrations due to active tubular secretion competition. Monitor for evidence of tenofovir toxicity.

Drug Interactions Probenecid Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine).

Drug Interactions Probenecid Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine).

Some examples of drugs that are eliminated by active tubular secretion include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions (5.6) ] .

Some examples of drugs that are eliminated by active tubular secretion include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions (5.3) and Clinical Pharmacology (12.3) ] .

Some examples of drugs that are eliminated by active tubular secretion include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions (5.4) ] .

Some examples of drugs that are eliminated by active tubular secretion include, but are not limited to, acyclovir, cidofovir, ganciclovir, valacyclovir, valganciclovir, aminoglycosides (e.g., gentamicin), and high-dose or multiple NSAIDs [see Warnings and Precautions (5.5) ] .

7.4 Drugs without Clinically Significant Interactions with PREVYMIS No clinically significant interactions were observed in adult clinical drug-drug interaction studies of letermovir and acyclovir, digoxin, mycophenolate mofetil, fluconazole, itraconazole, posaconazole, ethinyl estradiol, and levonorgestrel.

Examples Acyclovir, ganciclovir, probenecid, valacyclovir, valganciclovir Combination Oral Contraceptives Clinical Impact Concomitant use with Mycophenolate Mofetil decreased the systemic exposure to levonorgestrel, but did not affect the systemic exposure to ethinylestradiol [see Clinical Pharmacology (12.3) ] , which may result in reduced combination oral contraceptive effectiveness.