Ganciclovir Tenofovir

Allopurinol increases didanosine plasma concentrations and their coadministration is not recommended. Ganciclovir, tenofovir and disoproxil also increase didanosine plasma concentrations, and dose reduction is recommended. Conversely, methadone decreases didanosine plasma concentrations, and appropriate doses for the combination have not been established. Didanosine should not be administered with drugs that cause pancreatic or neurotoxicity. Ribavirin increases its risk of toxicity and should not be coadministered. 

Other drugs that are commonly implicated in causing ARF include acyclovir, adefovir, carboplatin, cidofovir, cisplatin, foscarnet, ganciclovir, indinavir, methotrexate, pentamidine, ritonavir, sulfinpyrazone, and tenofovir.45... 

Drugs eliminated by the kidneys Coadministration of tenofovir with drugs that are eliminated by active tubular secretion may increase serum concentrations of tenofovir and/or the coadministered drug. Some examples include, but are not limited to, acyclovir, adefovir dipivoxil, cidofovir, ganciclovir, valacyclovir, and valganciclovir. Drugs that decrease renal function also may increase serum concentrations of tenofovir. 

The buffer in didanosine tablets and powder interferes with absorption of indinavir, delavirdine, atazanavir, dapsone, itraconazole, and fluoroquinolone agents therefore, administration should be separated in time. Serum levels of didanosine are increased when -administered with tenofovir or ganciclovir, and are decreased by atazanavir, delavirdine, ritonavir, tipranavir, and methadone (Table 49-4). 

Didanosine Tenofovir, ganciclovir Atazanavir, delavirdine, ritonavir, tipranavir... 

Gastrointestinal complaints (eg, nausea, diarrhea, vomiting, flatulence) are the most common adverse effects but rarely require discontinuation of therapy. Other potential adverse effects include headache and asthenia. Tenofbvir-associated proximal renal tubulopathy causes excessive renal phosphate and calcium losses and 1-hydroxylation defects of vitamin D, and preclinical studies in several animal species have demonstrated bone toxicity (eg, osteomalacia). Monitoring of bone mineral density should be considered with long-term use in those with risk factors for or with known osteoporosis, as well as in children. Reduction of renal function over time, as well as cases of acute renal failure and Fanconi s syndrome, have been reported in patients receiving tenofovir alone or in combination with emtricitabine. For this reason, tenofovir should be used with caution in patients at risk for renal dysfunction. Tenofovir may compete with other drugs that are actively secreted by the kidneys, such as cidofovir, acyclovir, and ganciclovir. 

NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS GANCICLOVIRAfALGANCIC LOVIR 1. T adverse effects with tenofovir, zidovudine and possibly didanosine, lamivudine and zalcitabine 2. Possibly 1 efficacy of ganciclovir 1. Uncertain possibly additive toxicity. Lamivudine may compete for active tubular secretion in the kidneys 2. Uncertain L bioavailability 1. Avoid if possible otherwise monitor FBC and renal function weekly. It has been suggested that the dose of zidovudine should be halved from 600 mg to 300 mg daily. Monitor for peripheral neuropathy, particularly with zalcitabine 2. Uncertain clinical significance if in doubt, consider alternative cytomegalovirus prophylaxis... 

Tenofovir (TDF) Viread 300 mg tablet fV aminoglycosides, acyclovir, famciclovir, ganciclovir, valacyclovir, cidofovir... 

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