Foscarnet adverse effects

Amphotericin B Azoles Nephrotoxins (e.g, aminoglycosides, cidofovir, cyclosporine, foscarnet, pentamidine) See Chap. 125 in Pharmacotherapy A Pathophysiologic Approach, seventh edition, page 1998. Additive adverse effects Monitor renal function... 

The most clinically significant adverse effect of foscarnet is renal impairment. Nephrotoxicity is most likely to occur during the second week of induction therapy but may occur at any time during induction or maintenance therapy. Serum creatinine levels may be elevated in up to 33 to 50% of patients this effect is usually reversible upon drug discontinuation. Dehydration, previous renal impairment, and concurrent administration of other nephrotoxic drugs increase the risk of renal toxicity. Infusion of fluids along with foscarnet decreases the likelihood of renal impairment to about 12%. Dosage adjustment is required for patients with renal insufficiency. 

For each patient, select the drug that most likely caused the adverse effect Acyclovir Amantadine Dideoxycytldlne Foscarnet Ganciclovir Idoxuridine... 

Adverse Effects. The primary problem associated with foscarnet is impaired renal function, including acute tubular necrosis. Hematologic disorders (anemia, granulocytopenia, leukopenia), gastrointestinal disturbances (cramps, nausea, vomiting), and CNS toxicity (confusion, dizziness) may also occur during foscarnet treatment. 

The primary adverse effect of intravenous cidofovir is a dose-dependent nephrotoxicity. Concurrent administration of other potentially nephrotoxic agents (eg, amphotericin B, aminoglycosides, nonsteroidal anti-inflammatory drugs, pentamidine, foscarnet) should be avoided. Prior administration of foscarnet may increase the risk of nephrotoxicity. Other potential side effects include uveitis, decreased intraocular pressure, and probenecid-related hypersensitivity reactions. Neutropenia and metabolic acidosis are rare. The drug caused mammary adenocarcinomas in rats and is embryotoxic. 

LAMIVUDINE, TENOFOVIR, ZALCITABINE FOSCARNET SODIUM t adverse effects with tenofovir and possibly lamivudine and zalcitabine Uncertain possibly additive toxicity via competition for renal excretion Avoid if possible otherwise monitor FBC and renal function weekly... 

The second most common adverse effect of foscarnet is symptomatic hjrpocalcemia, which may be responsible for the cardiac dysrhythmias and seizures that occur after acute overdose or excessively rapid infusion of foscarnet. Foscarnet stimulates the release of parathyroid hormone, which raised concerns about long-term administration (8). However, in a study of seven patients receiving a 14-day foscarnet induction regimen, there were no changes in calcium or phosphate metabolism (9). 

Foscarnet 40-80 mgIVq. 8 hr 85% 40-20 mg q. 8-24 hr, according to Nephrotoxic, neurotoxic adverse effects are hypocaicemia, hypophosphatemia, hvoomaqnesemia.and hvookaiemia Dose after dialysis Dose for GFR<10 ml/min Dose for GFR 10-50 ml/min... 

The antiherpes drugs include acyclovir, ganciclovir, and foscarnet. Famciclovir and valacydovir are j newer drugs very similar to acyclovir. All inhibit viral DNA polymerase. Acyclovir and ganciclovir do so j by first being phosphorylated by viral enzymes. As well as acting as a polymerase inhibitor, acyclovir j j triphosphate is incorporated into the viral DNA where it acts as a chain terminator. The mechanisms of j j action, activities, clinical uses, and adverse effects are discussed, j... 

Clinical uses and toxicity The drug is used for prophylaxis and treatment of cytomegalovirus (CMV) infections (including CMV retinitis) and has activity against ganciclovir-resistant strains of this virus (Table 49-1). Foscarnet inhibits herpes DNA polymerase in acyclovir-resistant strains that are thymidine kinase-deficient and may suppress such resistant herpetic infections in patients with AIDS. Adverse effects include nephrotoxicity (30% incidence) with disturbances in electrolyte balance (especially hypocalcemia), genitourinary ulceration, and CNS effects (headache, hallucinations, seizures). 

Acyclovir-resistant HSV has been isolated from patients with AIDS. The primary mechanism of resistance appears to be a deficiency in viral thymidine kinase. Strategies that have been employed for management of severe acyclovir-resistant HSV infections include increasing the dose of acyclovir, discontinuing acyclovir, and use of an alternative antiviral agent. Vidarabine and foscarnet, because they do not require phosphorylation by thymidine kinase, are examples of potential alternative agents. A randomized comparison of foscarnet and vidarabine indicated that foscarnet is more effective and associated with fewer adverse reactions than vidarabine. ... 

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