Drug Topics - February 2009 - (Page 43)

CONTINUING EDUCATION surgery. Compared to currently available ophthalmic corticosteroids, it is a therapeutic advance. Indication: Diﬂuprednate is indicated for the treatment of inﬂammation and pain associated with ocular surgery. Pharmacology: Like all corticosteroids, diﬂuprednate inhibits the inﬂammatory response to a variety of inciting agents that may delay or slow healing. Precautions: Diﬂuprednate is contraindicated in most viral diseases of the cornea and conjunctiva, mycobacterial infection of the eye, and fungal diseases of ocular structures. Secondary bacterial or fungal ocular infection may occur because the host response is suppressed. Dosage and availability: The dose of diﬂuprednate is one drop into the conjunctival sac of the affected eye(s) 4 times daily, beginning 24 hours after surgery and continuing through the ﬁrst 2 weeks of the postoperative period, followed by 2 times daily for a week, with a tapering-off period based on the response. Diﬂuprednate is available as a 0.05 percent topical ophthalmic emulsion. Patient counseling: Patients should be told that diﬂuprednate can reduce the inﬂammation and pain associated with ocular surgery. Inform patients that the product is sterile and that, to prevent contamination, the dropper tip should not touch any surface. Contact lenses should not be worn while the patient is using this therapy. ELTROMBOPAG (Promacta, GlaxoSmithKline). FDA rating: 1-P,O,E,T (E = drug for severely debilitating or life-threatening illness). Eltrombopag is the ﬁrst oral agent approved to treat chronic immune (idiopathic) thrombocytopenic purpura (ITP) that directly stimulates platelet production. It is a therapeutic advance in patients who are refractory to conventional therapy. Indication: Eltrombopag is indicated for the treatment of thrombocytopenia in patients with chronic ITP who have had an insufﬁcient response to corticosteroids, immunoglobulins, or splenectomy. Eltrombopag should be used only in patients with ITP whose degree of thrombocytopenia and clinical condition increase the risk for bleeding. It should not be used in an attempt to normalize platelet counts. Pharmacology and pharmacokinetics: Eltrombopag is an orally bioavailable, small-molecule thrombopoietin (TPO) receptor agonist that interacts with the transmembrane domain of the human TPO-receptor. Studies involving administration of a polyvalent cationcontaining antacid and a standard high-fat breakfast concomitantly with eltrombopag demonstrated decreased eltrombopag absorption. The drug is extensively metabolized. CYP1A2 and 2C8 and UTG1A1 and 1A3 are responsible for oxidative and conjugative metabolism, respectively. Precautions: Eltrombopag may cause hepatotoxicity and bone marrow toxicity. Liver enzymes and bilirubin must be measured before initiation of treatment and regularly during treatment. Discontinuation may be necessary. Complete blood counts (CBC), including platelet counts, and peripheral blood W W W.D R U GTO P I C S .C O M smears must be monitored regularly during treatment; monitoring of platelet counts must continue until at least 4 weeks after discontinuation. Because of these risks, eltrombopag is available only through a restricted drug distribution program, PROMACTA CARES. Drug interactions: Eltrombopag is a substrate of CYP1A2 and CYP2C8 based on in vitro studies. Clinical studies have not established the signiﬁcance of inducer/inhibitor co-administration. Because of the risk of interaction, more intense monitoring is required if concomitant therapy is attempted. Eltrombopag is an inhibitor of the organic anion transporting polypeptide OATP1B1. Dose reduction of substrates of this transporter should be considered. Adverse effects: The most common adverse reactions were nausea, vomiting, menorrhagia, myalgia, paresthesia, cataract, dyspepsia, ecchymosis, thrombocytopenia, increased ALT/AST, and conjunctival hemorrhage. Dosage and availability: For most patients, the starting dose of eltrombopag is 50 mg once daily. Dosage should not exceed 75 mg. Eltrombopag should be discontinued if the platelet count does not increase after 4 weeks at the maximum dose. The daily dose should be adjusted to achieve and maintain a platelet count ≥50 x 10(9)/L in order to reduce the risk of bleeding. Eltrombopag is available as 25- and 50-mg tablets. Patient counseling: Inform patients that eltrombopag is administered to achieve and maintain a platelet count necessary to reduce the risk of bleeding. Inform them of the risks associated with therapy, including liver problems, bone marrow changes, high or low platelet counts, and worsening of blood cancers. to screen for drug interactions. To screen for drug interactions, ask what other medications patients are taking. Patients should be instructed to avoid antacids, multivitamins, and mineral supplements both 4 hours before and 4 hours after taking this product. Patients should take this medication on an empty stomach (1 hour before or 2 hours after a meal). Go over the patient counseling information and medication guide and be available for further questions. ETRAVIRINE (Intelence, Tibotec). FDA rating: 1P,E,T. Ertavirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used in treatment-experienced patients resistant to standard therapy. It is a treatment advance for these patients, whose therapeutic options are limited. Indication: Etravirine is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in treatment-experienced adult patients, who show evidence of viral replication and HIV-1 strains resistant to an NNRTI and other antiretroviral agents. In patients who have experienced virologic failure on an NNRTI-containing regimen, etravirine should not be used in combination with only NRTIs. The safety and efﬁcacy of etravirine have not been established in pediatric patients or treatment-naïve adult patients. Pharmacology and pharmacokinetics: Etravirine is an NNRTI of HIV-1. Expect cross-resistance to all NNRTIs in patients who experience virologic failure with a regimen that includes etravirine. Februar y 2009 DRUG TOPICS 43 http://WWW.DRUGTOPICS.COM

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Drug Topics - February 2009 Contents Health-System Edition Group Attempts to Resurrect Pain Care Act HSE Business Management HSE Clinical Letters Up Front Up Front in Depth Community Practice Niche Pharmacies Serve Special Populations Special Report Oral Oncology Drugs New Drugs Update 2008 Approvals OTC New Products Viewpoint

Drug Topics - February 2009

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