Risedronate

• Osteoporosis
• Paget's Disease of Bone
• Glucocorticoid-Induced Osteoporosis
• Postmenopausal Bone Loss

Risedronate is a nitrogen-containing bisphosphonate used to prevent and treat osteoporosis, Paget's disease of bone, and glucocorticoid-induced osteoporosis. It reduces bone resorption and fracture risk.

Mechanism of Action

Risedronate inhibits osteoclast-mediated bone resorption:

• Binds to hydroxyapatite: Concentrates at sites of active bone remodeling
• Inhibits farnesyl pyrophosphate synthase: Key enzyme in the mevalonate pathway
• Disrupts osteoclast function: Prevents prenylation of small GTPases essential for osteoclast activity
• Induces osteoclast apoptosis: Leads to reduced bone resorption
• Improves bone mineral density: Results in decreased fracture risk

Effects persist for months to years after discontinuation due to incorporation into bone matrix.

Available Formulations

• Immediate-release tablets: 5 mg (daily), 30 mg (Paget's), 35 mg (weekly), 150 mg (monthly)
• Delayed-release tablets: 35 mg (weekly, taken immediately after breakfast)

Medical Uses

FDA-Approved Indications:

• Prevention and treatment of postmenopausal osteoporosis
• Treatment to increase bone mass in men with osteoporosis
• Prevention and treatment of glucocorticoid-induced osteoporosis
• Paget's disease of bone

Dosing Guidelines

Postmenopausal Osteoporosis:

• 5 mg daily, OR
• 35 mg weekly, OR
• 150 mg monthly
• Delayed-release: 35 mg weekly immediately after breakfast

Osteoporosis in Men:

• 35 mg weekly

Glucocorticoid-Induced Osteoporosis:

• 5 mg daily

Paget's Disease:

• 30 mg daily for 2 months
• Retreatment may be considered after 2-month observation period if needed

Important Safety Information

Contraindications:

• Hypocalcemia
• Inability to sit or stand upright for at least 30 minutes
• Esophageal abnormalities that delay emptying (stricture, achalasia)
• Known hypersensitivity to risedronate

Warnings and Precautions:

• Esophageal adverse reactions: Esophagitis, esophageal ulcers, strictures
• Osteonecrosis of the jaw: Associated with bisphosphonate use
• Atypical femur fractures: Low-energy subtrochanteric and diaphyseal fractures
• Severe bone, joint, or muscle pain: May occur at any time during treatment
• Hypocalcemia: Correct before initiating; supplement with calcium and vitamin D

Drug Interactions

• Calcium supplements, antacids, oral medications with divalent cations: Impair absorption; separate by at least 30 minutes
• PPIs, H2 antagonists: May reduce absorption of delayed-release formulation (take with food)
• NSAIDs: May increase GI adverse effects

Administration Instructions

Immediate-Release:

• Take first thing in the morning on empty stomach with 6-8 oz plain water
• Remain upright (sitting or standing) for at least 30 minutes
• Wait at least 30 minutes before eating, drinking, or taking other medications

Delayed-Release:

• Take immediately after breakfast with at least 4 oz plain water
• Remain upright for at least 30 minutes
• Do not take on an empty stomach

Special Populations

• Renal Impairment: Not recommended if CrCl <30 mL/min
• Hepatic Impairment: No adjustment needed
• Pregnancy: Not recommended
• Lactation: Not recommended
• Pediatric: Not approved for children