R. Kelen
Union University
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Featured researches published by R. Kelen.
Pain Medicine | 2013
Patricia Richards; Dennis S Riff; R. Kelen; Warren Stern
Objective Compare the efficacy and tolerability of the dual-opioid, Q8003® (morphine/oxycodone combination) 12 mg/8 mg to morphine 12 mg or oxycodone 8 mg in subjects following bunionectomy surgery. Design This was a randomized, double-blind study. Setting Hospitalized patients. Patients Healthy men or women aged ≥18 years with moderate or severe pain (score ≥2 on a 4-point Likert scale) and ≥4 on the 11-point numerical pain rating scale following surgery. Interventions Study medication was initiated after surgery and was given for 48 hours. Outcomes The primary efficacy variable was mean sum of the pain intensity difference (SPID) scores from the postsurgical baseline. Results Five hundred twenty-two subjects were randomized; 31 (5.9%) discontinued, including 19 (3.6%) for adverse events. The mean total morphine equivalent dose (MED) was 182.7 mg from Q8003 12 mg/8 mg, 92.4 mg for morphine 12 mg, and 92.1 mg for oxycodone 8 mg. SPID from baseline over 24 hours and SPID from baseline over 48 hours were significantly (P < 0.02) higher for Q8003 12 mg/8 mg vs morphine 12 mg or oxycodone 8 mg. Significantly (P < 0.015) fewer subjects in the Q8003 group required ibuprofen rescue medication, used lower doses of rescue medication, and had a longer median time to first use of rescue medication. Oxygen desaturation <90% occurred in 5.3% with Q8003, 2.8% with morphine 12 mg, and 2.3% with oxycodone 8 mg, and the cumulative median dose at first desaturation was twofold greater with Q8003. Conclusion Q8003 provided superior efficacy to its individual components at twice the MED with only a modest increase in the incidence of adverse events.
Clinical Therapeutics | 2013
Patricia Richards; Joseph Gimbel; Harold S. Minkowitz; R. Kelen; Warren Stern
BACKGROUND In acute pain models, coadministration of low doses of morphine and oxycodone markedly enhanced analgesia relative to either opioid given alone. Enhanced analgesia with coadministration of morphine and oxycodone has also been reported in acute and chronic moderate to severe pain conditions during double-blind studies. OBJECTIVE The goal of this study was to compare the efficacy and tolerability of a flexible dose regimen of the morphine/oxycodone combination versus oxycodone/acetaminophen and fixed low-dose morphine/oxycodone. METHODS This was a 5-center, randomized, open-label study of hospitalized patients (n = 44) with acute moderate to severe postoperative pain after total knee arthroplasty. Inpatients were randomized to a flexible dose regimen of morphine/oxycodone (3 mg/2 mg to 24 mg/16 mg), fixed low-dose morphine/oxycodone regimen (3 mg/2 mg), or oxycodone/acetaminophen (5 mg/325 mg). Treatment was initiated following surgery after intravenous (IV) morphine patient-controlled analgesia. An algorithm was evaluated for converting the patient-controlled analgesia morphine dose to an initial oral dose of morphine/oxycodone. The primary efficacy variable was the time-weighted sum of pain intensity difference from 0 to 48 hours. RESULTS The median values for the sum of the pain intensity difference from 0 to 48 hours for the morphine/oxycodone flexible dose and oxycodone/acetaminophen were similar and approximately twice that of fixed morphine/oxycodone 3 mg/2 mg (148.0, 139.5, and 71.3, respectively). Moderate to severe gastrointestinal adverse events occurred in 50% of patients in the oxycodone/acetaminophen group compared with 15% of the equianalgesic morphine/oxycodone group. On several items of the Brief Pain Inventory (general activity, walking ability, and sleep), the morphine/oxycodone flexible dose produced greater benefit than oxycodone/acetaminophen. CONCLUSIONS Flexible dose morphine/oxycodone was superior to low-dose morphine/oxycodone and comparable to oxycodone/acetaminophen. Flexible dose morphine/oxycodone-treated patients had a lower rate of moderate to severe nausea or vomiting than equianalgesic oxycodone/acetaminophen-treated patients. Thus, morphine/oxycodone offers an attractive alternative to oxycodone/acetaminophen for the management of moderate to severe postoperative pain.
Clinical Therapeutics | 2012
Robin Joppich; Patricia Richards; R. Kelen; Warren Stern; Kourosh Zarghooni; Christina Otto; Andreas Böhmer; F. Petzke; Tilman Treptau; Rolf Lefering; Holger Bäthis; Edmund Neugebauer
BACKGROUND Results from studies with a combination of oral morphine and oxycodone in postsurgical patients demonstrate significant analgesia and a tolerability profile comparable to other pain medications at morphine-equivalent doses. However, an intravenous (IV) combination has not previously been studied. OBJECTIVE This study evaluated the efficacy and tolerability of IV morphine versus a combination of IV morphine and IV oxycodone in a 1:1 ratio. METHODS This was a 2-center, randomized, double-blind, active-controlled pilot trial of 40 patients who had undergone total hip replacement. After surgery, when pain levels reached ≥4 (on the 11-point Numerical Pain Rating Scale), patients were randomized to 1 of 2 treatment groups. In part 1 of the study, patients were dosed every 5 minutes for the first 65 minutes (up to 13 doses) with study drug, provided that vital signs criteria were met. After an initial loading dose of either morphine 1.5 mg coadministered with oxycodone 1.5 mg or morphine 3 mg alone, patients received IV morphine 1.5 mg or IV morphine 0.75 mg/IV oxycodone 0.75 mg every 5 minutes. If patients achieved a pain score of 2 or experienced intolerable adverse events to drug when stable, they were permitted to enter part 2. In part 2, patients received blinded study medication (IV morphine plus IV oxycodone [0.5 mg/0.5 mg] or 1 mg IV morphine alone) via patient-controlled analgesia (PCA) for 47 hours. RESULTS At baseline, treatment groups were comparable except for a higher proportion of females in the IV morphine group. Baseline pain intensity averaged 7 on the Numerical Pain Rating Scale of 0 to 10. One patient in the morphine group and 2 patients in the morphine/oxycodone group discontinued the study. The sum of the pain intensity differences from baseline to 65 minutes during the dose-titration phase was 1.8 for morphine alone versus 2.7 for morphine/oxycodone (P = 0.12); these values occurred at the same median number of doses (12) for each group. In part 2 (PCA dosing) of the study, similar levels of analgesia were achieved. During the study, 24% of the IV morphine/oxycodone group and 37% of the IV morphine group experienced nausea, and 10% of the IV morphine/oxycodone group and 16% of the IV morphine group had emesis. Two patients in the IV morphine/oxycodone group and 4 in the IV morphine alone group experienced oxygen desaturation. CONCLUSIONS The combination of IV morphine and oxycodone provided pain relief with an acceptable tolerability profile in these patients experiencing moderate to severe postoperative pain. However, as an explorative pilot study, the power was not adequate to demonstrate statistical significance for differences between IV morphine/oxycodone and IV morphine alone. European Clinical Trials Data Base registration code: EudraCT-No. 2008-008527-14.
The Journal of Pain | 2011
Patricia Richards; R. Kelen; Harold S. Minkowitz; Warren Stern
The Journal of Pain | 2010
Lynn R. Webster; Joel S. Owen; Inger Darling; Patricia Richards; R. Kelen; Warren Stern
The Journal of Pain | 2011
Patricia Richards; Warren Stern; R. Kelen; N. Huang
The Journal of Pain | 2011
Patricia Richards; R. Kelen; M. Spychala; Warren Stern
Archive | 2016
Patricia Richards; Dennis S Riff; R. Kelen; Warren Stern
The Journal of Pain | 2011
Patricia Richards; R. Kelen; Warren Stern; E. Neugebauer; C. Otto; F. Petzke; R. Joppich; H. Bäthis
The Journal of Pain | 2010
Lynn R. Webster; Patricia Richards; R. Kelen; Warren Stern