FONAT

What it is

FONAT is a composite pack containing alendronic sodium and colecalciferol, and calcium carbonate. The pack contains Alendronate plus D3 Sandoz 70 mg/140 μg (alendronic acid as alendronate sodium and colecalciferol [vitamin D3]) in addition to Calcium Sandoz (calcium carbonate). Each tablet of Alendronate plus D3 Sandoz 70 mg/140 μg contains 91.37 mg of alendronate sodium, which is the molar equivalent to 70 mg of alendronic acid, and 140 μg of colecalciferol equivalent to 5600 IU vitamin D. Each tablet of Calcium Sandoz contains 1250 mg calcium carbonate which is equivalent to 500 mg elemental calcium. Alendronate sodium is a bisphosphonate that acts as a potent, specific inhibitor of osteoclast-mediated bone resorption. Colecalciferol (vitamin D3) is a secosterol that is the natural precursor of the calcium-regulating hormone calcitriol (1,25-dihydroxyvitamin D3).

Approved indications

FONAT is indicated for the treatment of osteoporosis in select patients where vitamin D and calcium supplementation is recommended.

Dosing overview

One tablet of Alendronate plus D3 Sandoz 70 mg/140 μg should be taken on the first day. Beginning on the next day, one or two Calcium Sandoz tablets should be taken daily for 6 days. This 7 day cycle should be repeated each week. With this regimen Alendronate plus D3 Sandoz 70 mg/140 μg and Calcium Sandoz are not taken on the same day.

Key safety warnings

Severe oesophageal ulceration has been reported in patients taking alendronate. Alendronate, like other bisphosphonates, may cause local irritation of the upper gastrointestinal mucosa. Oesophageal adverse experiences, such as oesophagitis, oesophageal ulcers and oesophageal erosions, rarely followed by oesophageal stricture or perforation, have been reported in patients receiving treatment with alendronate. In some cases these have been severe and required hospitalisation. The risk of severe oesophageal adverse experiences appears to be greater in patients who lie down after taking alendronate sodium with colecalciferol and/or who fail to swallow it with the recommended amount of water, and/or who continue to take alendronate sodium with colecalciferol after developing symptoms suggestive of oesophageal irritation. To facilitate delivery to the stomach and thus reduce the potential for oesophageal irritation patients should be instructed to swallow each tablet of alendronate sodium with colecalciferol with a full glass of water. Patients should be instructed not to lie down for at least 30 minutes and until after their first food of the day. Localised osteonecrosis of the jaw (ONJ), generally associated with tooth extraction and/or local infection (including osteomyelitis) with delayed healing, has been reported rarely with oral bisphosphonates including alendronate. As of May 2004, ONJ after bisphosphonate treatment has been described in a total of 99 cases in two large case series, 7 of which were taking oral bisphosphonates. As of 3 Nov 2006, the Australian Adverse Drug Reactions Advisory Committee has received 25 reports of ONJ in patients receiving alendronate. A small number of long-term (usually longer than three years) alendronate-treated patients developed stress fractures of the proximal femoral shaft (also known as insufficiency fractures), some of which occurred in the absence of apparent trauma. Some patients experienced prodromal pain in the affected area, often associated with imaging features of stress fracture, weeks to months before a complete fracture occurred. Bone, joint, and/or muscle pain has been reported in patients taking bisphosphonates. In post-marketing experience, these symptoms have rarely been severe and/or incapacitating. The time to onset of symptoms varied from one day to several months after starting treatment. Most patients had relief of symptoms after stopping treatment.

Contraindications

FONAT is contraindicated in patients with abnormalities of the oesophagus which delay oesophageal emptying such as stricture or achalasia, inability to stand or sit upright for at least 30 minutes, hypersensitivity to any component of the product, or hypocalcaemia. The calcium carbonate component is contraindicated in patients with hypercalcaemia, severe hypercalciuria, or hypersensitivity to any component of the product.

PBS listing

In July 2016, the PBAC recommended a restricted benefit listing of alendronic acid 70 mg effervescent tablets for the treatment of osteoporosis, on the basis of bioequivalence to alendronate tablets.

Regulatory history

FONAT alendronic acid 70 mg tablet blister pack was first listed on the ARTG on 15 October 2008. In July 2016, the PBAC recommended a restricted benefit listing of the product for the treatment of osteoporosis.