Drug Topics - April 14, 2008 - (Page 16)

16 DRUG TOPICS APRIL 14, 2008 www.drugtopics.com Rx Care Active metabolite gives new life to antidepressant Heidi Belden, Pharm.D. day. Tablets should be taken at the same time each day and swallowed whole, not crushed or dissolved. When treatment is being discontinued, gradual dose reduction is recommended to minimize discontinuation symptoms. These symptoms occurred more often in patients who had a longer duration of therapy. Breden wonders if the benefit of desvenlafaxine over venlafaxine is similar to the perceived benefit of escitalopram over citalopram, where escitalopram may offer better antidepressant activity based on the fact that it contains only the pharmacologically active S-isomer of the drug. Citalopram itself is a mix of both the S- and R-isomers, the latter of which has little to no antidepressant effect and may theoretically dilute the action of citalopram or contribute to side effects. “Desvenlafaxine may provide a benefit in hepatically impaired patients and those who experienced increases in blood pressure when taking venlafaxine,” Breden pointed out. Although elevated blood pressure has occurred with desvenlafaxine, and hypertension should be controlled prior to initiating treatment and monitored regularly, the proportion of patients showing sustained elevation of supine diastolic blood pressure in clinical trials appears negligible. The label for desvenlafaxine includes the black box warning for antidepressants and the increased risk for suicidality. Patients should be monitored for clinical worsening and suicide risk while taking the drug. In addition, the label contains warnings for serotonin syndrome, activation of mania/hypomania, cholesterol and triglyceride elevation, interstitial lung disease and eosinophilic pneumonia, and mydriasis. Patients should be cautioned about the increased risk of bleeding associated with the concomitant use of desvenlafaxine with aspirin or other drugs that affect coagulation. Patients with narrow-angle glaucoma and cardiovascular disease should use desvenlafaxine with caution. The most commonly observed adverse effects during clinical trials included nauTips to remember Pristiq sea, dizziness, hyperhidrosis, insomnia, conThe recommended dose of Pristiq is 50 mg once daily with or stipation, somnolence, male sexual dysfuncwithout food. tion, and anxiety, among others. Pristiq should not be taken with a monoamine oxidase inhibiBreden believes that patients who don’t tor or within 14 days of stopping an MAOI. respond to venlafaxine at a low dose, but Pristiq is available in 50-mg and 100-mg tablets. cannot tolerate its side effects at a high dose, may be candidates for desvenlafaxine. DT I n May 2008, Wyeth will begin rolling out its new serotonin-norepinephrine reuptake inhibitor (SNRI), desvenlafaxine, the major active metabolite of the company’s current extended-release blockbuster SNRI venlafaxine (Effexor XR), scheduled to go off patent shortly. The new drug, to be marketed as Pristiq, was approved by the Food & Drug Administration in February for the treatment of major depressive disorder. According to Ericka Breden, Pharm. D., BCPP, CGP, clinical assistant professor of pharmacy and psychiatry at Virginia Commonwealth University Health System, while lower doses would inhibit the reuptake of serotonin with venlafaxine, higher doses were necessary to inhibit norepinephrine (NE) reupake. “It appears that desvenlafaxine is being marketed at one dose—50 mg—and as inhibiting both serotonin and NE reuptake,” she said. In fact, according to Wyeth, desvenlafaxine does not require titration and allows physicians to start patients at the recommended therapeutic dose. The drug is the active metabolite of venlafaxine and is delivered without going through the CYP2D6 metabolic pathway. This could be beneficial when the drug is coadministered with other drugs metabolized by the same isoenzyme. In clinical studies, doses of 50 to 400 mg per day were shown to be effective, although no additional benefit was demonstrated at doses greater than 50 mg per day and adverse events and discontinuations were more frequent at higher doses. According to the prescribing information, patients with severe renal impairment and end-stage renal disease should take 50 mg every other http://www.drugtopics.com

Table of Contents Feed for the Digital Edition of Drug Topics - April 14, 2008

Drug Topics - March 14, 2008 Contents Latebreakers Letters: Students Need Grounding in Chemistry Pharmacy Directors Wary of Heparin Shortages Some E-prescribing Standards are Ready to Go, Others are Not News Briefs Nanotechnology: Big Stakes in a Small World Pay for Performance is Coming to Pharmacy Patient Safety Organizations Still Very Much in Planning Stage Reconciling Medications in Specialty Patients Poses More Challenges Pharmacy Outsourcing Still Much in Use by Hospitals Studied Extensively, New Drug-Eluting Stent Said to be Very Safe Prevention is Key in Treating C. Difficile Infections E-prescribing Grows in Massachusetts, but Other States Lag Behind Active Metabolite Gives New Life to Antidepressant NSAIDS not Recommended for Long-term Use in Osteoarthritis This Time R.Ph.s and States Are Ready for Tamper-Resistant Rx Pads Cardinal Caught Between DEA and Pharmacies over Diversion Control Medicating Kids: Still More Questions than Answers Schnucks Pharmacy: Drug Topics' Chain of the Year Panel Will Ask for a System for R.Ph. Practice Across State Lines FDA Safety Page: How to use Fentora Safely The Shining OTC/HBC Stars of 2007 Take a Look at These OTCs for Eye Health Technology Update: Google Offers a Sneak Peak at its Electronic Records Initiative Recent Advancements in HIV/AIDS Treatment New Products Advertisers Index Classified Viewpoint: Are State Boards of Pharmacy Abusing Their Power?

Drug Topics - April 14, 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.