With a total direct health expenditure of over $300 million dollars per annum, of which over 70% is due to the cost of pharmaceutical medications, osteoporosis is increasingly becoming a significant cost burden for the Australian healthcare system.
Oral bisphosphonates traditionally have poor bioavailability, which is more pronounced when not taken according to dosing instructions (i.e. half hour before food or beverage – apart from water).
Risedronate EC is listed on the PBS as a streamline authority as:-
Actonel EC Once A Week – risedronate EC 35mg
Actonel Combi EC – risedronate EC 35mg, calcium carbonate 1250mg
Actonel Combi D EC – risedronate EC 35mg, calcium carbonate 2500mg and cholecalciferol 880IU.
Risedronate EC provides efficacious therapy in the treatment of osteoporosis as it has a pH-sensitive enteric-coating which only allows it to dissolve in the small bowel after which a chelating agent, edetate disodium (EDTA), is then released to bind to calcium and other divalent cations (i.e. magnesium, iron, aluminium) to minimise chelation to risedronate.
Risedronate EC may be taken before, during, or after food with minimal interference to the optimal absorption of risedronate – thus allowing improved compliance for patients who struggle with the dosage requirements of standard oral bisphosphonates. Risedronate EC should still be taken separately from antacids and calcium, iron, or magnesium supplements to minimise potential interactions and reduced absorption.
Adverse effects remain similar to other oral bisphosphonates and include musculoskeletal pain and gastrointestinal effects (i.e. dyspepsia, nausea, abdominal pain).
Overall improvement in therapeutic benefit for the treatment of osteoporosis is expected to be observed due to the removal of interactions with food, beverage and dietary divalent cations.