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  Risedronate (Actonel)
 
Author: Donna Karasic, PharmD Last modified: April 4, 2002
 

  INDICATIONS

  • Glucocorticoid-induced Osteoporosis
  • Paget's Disease
  • Osteoporosis (prevention and treatment) in postmenopausal women
  • Osteoporosis in men (non-FDA approved use)
  • Primary Hyperparathyroidism (non-FDA approved use)
  • Hypercalcemia of malignancy (non-FDA approved use)

  DOSAGE

  • Glucocorticoid-induced osteoporosis: 5mg once a day
  • Paget's Disease: 30 mg once a day for 2 months; retreatment after at least 2 months observation may be considered
  • Osteoporosis (prevention and treatment) in postmenopausal women: 5mg once a day
  • Primary Hyperparathyroidism: 20 mg once a day
  • Hypercalcemia of Malignancy: 30mg once a day

  PHARMACOKINETICS

  • Specific pharmacokinetic data for risedronate are lacking
  • Bisphosphonates are poorly absorbed (approximately 0.63%)
  • Bisphosphonates are not metabolized
  • Food significantly impedes absorption
  • Bisphosphonates are quickly cleared from plasma, and 20%-60% of dose binds to bone within 12 to 24 hours. Following binding, it is retained in bone for several months
  • The elimination half-life is multi-phasic: the initial half-life is approximately 1.5 hours; the terminal exponential half-life is 480 hours

  ADVERSE EFFECTS

  • Asthenia (4.9%)
  • Headache (18%)
  • Dizziness (6.6%)
  • Diarrhea (19.7%)
  • Arthralgia (32.8%)
  • Flu-like symptoms (9.8%)
  • Rash (11.5%)
  • Gastritis, abdominal pain (11.5%)

  CONTRAINDICATIONS

  • Hypersensitivity to risedronate or other bisphosphonates
  • Hypocalcemia
  • Inability to sit/stand upright for at least 30 minutes
  • Renal impairment: creatinine clearance less than 30 ml/min

  DRUG INTERACTIONS

  • Antacids
  • Calcium
  • Magnesium

  FORMS

  • 5mg and 30mg tablets
  • Note: the 30mg tablet is for daily dosing; used in Paget\'s Disease

  MECHANISM OF ACTION

  • Risedronate is a potent bisphosphonate compound
  • Risedronate is chemically similar to other bisphosphonates; however, it contains a cyclic side chain
  • Mechanisms of action of antiresorptive activity are not fully understood, but may involve direct inhibition of mature osteoclast activity (ie, local interference of resorptive functions)
  • or by indirect inhibition of osteoblasts, preventing these cells from producing osteoclast-stimulating activity
 
IMPORTANT POINTS/RECOMMENDATIONS
  • The potency of risedronate is considerably greater than that of both first-generation (etidronate, clodronate) and second-generation (alendronate, pamidronate, tiludronate) compounds
  • Risedronate is at least 100 times as potent as pamidronate and alendronate, and over 1000 times as potent as etidronate
  • Despite its greater potency, comparisons with other bisphosphonates are needed to determine if this will correlate with superior efficacy in disorders associated with increased bone resorption
  • Instruct patients to take risedronate on an empty stomach, at least 30 minutes before the first food or drink of the day
  • Swallow tablet with a large glass of plain water (not mineral water or any other kind of liquid) and wait at least 30 minutes before eating or drinking anything or taking other medicines
  • Patients should sit or stand upright for at least 30 minutes after taking the dose
  • Do not use in patients with hypocalcemia, other bone and mineral metabolism disturbances; treat before starting bisphosphonate therapy
  • Risedronate may exacerbate dysphagia, esophagitis, esophageal or gastric ulcers
 
REFERENCES
  1. Hutchinson TA & Shahan DR (Eds) ;  Risedronate ;  MICROMEDEX Healthcare Series; MICROMEDEX, Greenwood Village, Colorado (edition expires 3-2002)

  2. Hebel SK, Kastrup EK (Eds) ;  Risedronate ;  Facts and Comparisons, St. Louis, MO (updated 2002)

Copyright © 2002 The Johns Hopkins University School of Medicine. All rights reserved.