Optinate Septimum (Risedronate 35 mg)

What Is Optinate Septimum and What Is It Used For?

Optinate Septimum belongs to the class of nitrogen-containing bisphosphonates, the most widely prescribed therapeutic group for the treatment and prevention of osteoporosis worldwide. The active ingredient, risedronate sodium, acts directly on bone tissue by inhibiting the farnesyl pyrophosphate synthase enzyme inside osteoclasts — the specialised cells that break down bone. By interrupting this metabolic pathway, risedronate reduces osteoclast activity and slows the rate of bone resorption. This allows bone formation by osteoblasts to outpace resorption, resulting in increased bone mineral density (BMD) and improved bone microarchitecture over time.

The “Septimum” in the brand name refers to the seven-day (weekly) dosing interval. The 35 mg weekly formulation was developed as a convenience-based alternative to the 5 mg daily regimen. Clinical trials have shown that weekly and daily dosing are therapeutically equivalent in terms of BMD increase and fracture risk reduction, but weekly dosing is consistently associated with better long-term adherence — a critical factor in a chronic condition such as osteoporosis where the therapeutic benefit depends on sustained treatment.

A distinguishing feature of Optinate Septimum is its gastro-resistant (enteric) coating. Standard film-coated risedronate dissolves in the stomach and must be taken on an empty stomach at least 30 minutes before breakfast. The enteric coating of Optinate Septimum is designed to prevent dissolution in the stomach and release the active ingredient in the proximal small intestine. This formulation strategy allows the tablet to be taken immediately after breakfast, a clinically relevant advantage for patients who find fasted morning dosing difficult. The bioequivalence of the gastro-resistant formulation to the standard formulation has been demonstrated in pharmacokinetic studies, and both forms have consistent efficacy in real-world practice.

Osteoporosis is a systemic skeletal disease characterised by low bone mass and deterioration of bone microarchitecture, leading to increased bone fragility and susceptibility to fracture. According to the World Health Organization (WHO), osteoporosis affects an estimated 200 million people globally, with one in three women and one in five men over the age of 50 experiencing an osteoporotic fracture during their lifetime. Hip fractures are associated with substantial morbidity, loss of independence, and a 20–25% increase in mortality in the year following fracture. Preventing fractures in high-risk individuals is therefore one of the most impactful interventions in geriatric medicine.

Optinate Septimum is specifically indicated for:

• Treatment of postmenopausal osteoporosis to reduce the risk of vertebral and hip fractures, including in women with severe (established) osteoporosis.
• Treatment of osteoporosis in men at high risk of fractures.
• Maintenance or prevention of osteoporosis in patients initiating or continuing long-term systemic corticosteroid therapy (in some markets and regulatory jurisdictions).

The efficacy of risedronate has been established in the landmark VERT (Vertebral Efficacy with Risedronate Therapy) trials, which demonstrated approximately 41–49% reduction in new vertebral fractures and approximately 39% reduction in non-vertebral fractures over three years. The HIP study further demonstrated a 30% reduction in hip fractures in women aged 70–79 years with confirmed osteoporosis. These findings are supported by multiple Cochrane systematic reviews and have been incorporated into international osteoporosis treatment guidelines from NICE, the National Osteoporosis Foundation, and the European Society for Clinical and Economic Aspects of Osteoporosis (ESCEO).

What Should You Know Before Taking Optinate Septimum?

Before starting treatment with Optinate Septimum, your doctor will assess your overall health, bone mineral density (typically measured by DXA scan), fracture history, and risk factors such as age, family history, prior fractures, smoking status, and concurrent medications. Baseline laboratory tests commonly include serum calcium, 25-hydroxyvitamin D, creatinine, alkaline phosphatase, and sometimes parathyroid hormone (PTH). Correcting nutritional deficiencies and metabolic abnormalities before initiating bisphosphonate therapy improves both safety and effectiveness.

Contraindications

Optinate Septimum must not be taken in the following situations:

• Known hypersensitivity to risedronate sodium, other bisphosphonates, or any of the excipients in the tablet.
• Hypocalcaemia — abnormally low calcium levels in the blood. Calcium deficiency must be corrected before starting bisphosphonate therapy, as further lowering of serum calcium can trigger symptomatic hypocalcaemia.
• Pregnancy — if there is any possibility of being pregnant, if you are pregnant, or if you are planning to conceive in the near future.
• Breastfeeding — risedronate should not be used in breastfeeding women.
• Severe renal impairment — creatinine clearance below 30 ml/min. Risedronate is primarily eliminated via the kidneys, and impaired clearance can lead to drug accumulation.
• Inability to stand or sit upright for 30 minutes after dosing — this population has a substantially increased risk of oesophageal adverse effects.

Warnings and Precautions

The following conditions warrant discussion with your doctor before initiating or continuing Optinate Septimum therapy. They do not always preclude use but may require enhanced monitoring, additional precautions, or alternative therapy.

Oesophageal and upper gastrointestinal disorders: Although the gastro-resistant coating of Optinate Septimum is designed to minimise direct contact between risedronate and the oesophageal mucosa, caution is still warranted in patients with a history of oesophageal disorders that delay oesophageal emptying, such as stricture or achalasia. Patients with active upper gastrointestinal issues — including dysphagia, symptomatic gastro-oesophageal reflux disease, gastritis, duodenitis, or ulcers — should be evaluated before starting therapy. If symptoms suggesting oesophageal reaction develop (pain on swallowing, difficulty swallowing, new or worsening heartburn, retrosternal pain), stop the medication and contact your doctor promptly.

Calcium and vitamin D status: Adequate calcium and vitamin D are essential for the therapeutic effect of bisphosphonates and for the prevention of hypocalcaemia during treatment. Vitamin D deficiency is common in older adults and should be corrected before starting Optinate Septimum. Many guidelines recommend routine supplementation of 800–1000 IU of vitamin D per day and a dietary calcium intake of approximately 1000–1200 mg per day (from diet and supplements combined).

Osteonecrosis of the jaw (ONJ): ONJ is a rare but clinically significant adverse event associated with bisphosphonate use. It is characterised by exposed, non-healing bone in the mandible or maxilla lasting more than eight weeks. The risk is substantially higher with intravenous high-dose bisphosphonates used in oncology than with oral bisphosphonates used for osteoporosis. Risk factors include invasive dental procedures, poorly fitting dentures, active dental or periodontal infection, smoking, diabetes, corticosteroid co-therapy, and concomitant cancer or cancer therapy. Before starting Optinate Septimum, routine dental examination and treatment of identified problems is recommended. Avoid invasive dental procedures during treatment when possible, and always inform your dentist that you are taking a bisphosphonate.

Atypical femoral fractures (AFF): Atypical low-trauma fractures of the femoral shaft have been reported in patients receiving long-term bisphosphonate therapy. These fractures typically follow prodromal thigh, groin, or hip pain for weeks or months before the actual fracture. They are often bilateral. The absolute risk is low but rises with longer treatment duration. The benefits of fracture prevention generally outweigh the AFF risk for patients with active osteoporosis, but periodic reassessment of treatment necessity is recommended after 3–5 years of therapy.

Osteonecrosis of the external auditory canal: Rare cases of osteonecrosis affecting the ear canal have been reported, mainly with long-term bisphosphonate use. Risk factors include steroid use, chemotherapy, local infection, trauma, and chronic ear problems. Contact your doctor if you develop persistent ear pain, discharge, or hearing loss during treatment.

Hepatic impairment: Risedronate undergoes minimal hepatic metabolism, and no specific dose adjustment is required in patients with liver disease. Data in severe hepatic impairment, however, are limited.

Elderly patients: No dose adjustment is required based on age alone. Older patients often have reduced renal function and multiple comorbidities; renal function should be assessed periodically.

Pregnancy and Breastfeeding

Optinate Septimum is contraindicated during pregnancy and breastfeeding. Bisphosphonates are incorporated into the bone matrix and can be gradually released over many years, meaning that potential foetal exposure may persist even after treatment is discontinued before conception. Animal studies have shown adverse effects at high doses, and human data are insufficient to exclude risk.

Women of childbearing potential should use effective contraception during treatment with Optinate Septimum. If pregnancy occurs or is suspected during therapy, discontinue the medication immediately and consult your doctor. Optinate Septimum is intended for postmenopausal women and men with osteoporosis; it is not indicated for pre-menopausal women of reproductive age except under very specific specialist circumstances.

Children and Adolescents

Optinate Septimum is not recommended for use in children or adolescents under 18 years of age. Safety and efficacy have not been established in this population. Paediatric osteoporosis is a rare and complex condition that requires specialist evaluation, and treatment decisions should be made by paediatric endocrinologists in tertiary settings.

Driving and Operating Machinery

Risedronate has no known clinically significant effect on the ability to drive or operate machinery. However, if you experience dizziness, severe musculoskeletal pain, or visual disturbances (rare), refrain from driving until the symptoms have resolved and you have consulted a healthcare professional.

How Does Optinate Septimum Interact with Other Drugs?

Drug interactions with risedronate are primarily pharmacokinetic rather than pharmacodynamic, and almost all are related to the absorption of the drug in the upper gastrointestinal tract. Because the oral bioavailability of risedronate is inherently low (approximately 0.63% of the dose is absorbed under fasting conditions), even modest reductions in absorption can have significant clinical consequences. Understanding and avoiding these interactions is essential to achieving the full therapeutic benefit of Optinate Septimum.

Major Interactions That Reduce Absorption

Substances containing polyvalent cations (calcium, magnesium, aluminium, iron, or zinc) form insoluble chelate complexes with the bisphosphonate group of risedronate, preventing its absorption. Co-administration should therefore be avoided.

Other Pharmacological Considerations

NSAIDs and aspirin: Non-steroidal anti-inflammatory drugs can cause upper gastrointestinal irritation and ulceration, and the combination with bisphosphonates may theoretically increase the risk of gastrointestinal adverse effects. The clinical significance of this interaction with gastro-resistant formulations such as Optinate Septimum is reduced, but caution and monitoring for GI symptoms remain prudent, especially in elderly patients or those with a prior history of peptic ulcer disease.

Proton pump inhibitors (PPIs) and H₂-receptor antagonists: These acid-suppressing medications may affect the dissolution profile of gastro-resistant tablets. The clinical impact in real-world practice has been modest in comparative studies, and concomitant use is not contraindicated. However, some osteoporosis guidelines note that long-term high-dose PPI use is independently associated with a small increase in fracture risk, and the clinical implication in combination with bisphosphonates remains an area of ongoing research.

Systemic corticosteroids: Long-term corticosteroid therapy causes glucocorticoid-induced osteoporosis, which is itself an indication for bisphosphonate therapy in some patients. While there is no pharmacokinetic interaction between corticosteroids and risedronate, the clinical contexts may overlap, and concomitant use is often appropriate under specialist guidance.

Histamine H₂-receptor antagonists: Ranitidine, famotidine, and similar drugs do not appear to cause clinically significant changes in risedronate pharmacokinetics.

Cytochrome P450 interactions: Risedronate is not metabolised by CYP450 enzymes and does not induce or inhibit them. Therefore, clinically relevant metabolic interactions with drugs such as warfarin, statins, antidepressants, or antiepileptics are unlikely.

What Is the Correct Dosage of Optinate Septimum?

Correct dosing and timing are critical to both the efficacy and safety of Optinate Septimum. Because bisphosphonate absorption is so sensitive to food, beverages, and other medications, strict adherence to the administration schedule is one of the most important factors determining treatment success.

Adults

The tablet must be swallowed whole. Do not chew, crush, break, or suck on the tablet — doing so damages the enteric coating and exposes the oesophagus and stomach to irritation. Use plain tap water for dosing; mineral water, sparkling water, coffee, tea, juice, and soft drinks are not suitable substitutes because of their mineral or caloric content.

In most clinical protocols, Optinate Septimum is prescribed alongside calcium (1000–1200 mg/day) and vitamin D (800–1000 IU/day) supplements if dietary intake or sun exposure is insufficient. These supplements should be taken at a different time of day from the bisphosphonate dose to avoid interference with absorption.

Treatment Duration

The optimal duration of oral bisphosphonate therapy is an area of active clinical debate. Most major guidelines — including those from the National Institute for Health and Care Excellence (NICE), the National Osteoporosis Foundation (NOF), the American Association of Clinical Endocrinologists (AACE), and the European Society for Clinical and Economic Aspects of Osteoporosis (ESCEO) — recommend reassessing the need for continued treatment after 3–5 years. At this point, patients at low fracture risk may be candidates for a “drug holiday”, while those at continued high risk typically continue therapy. Decisions should be individualised based on fracture history, bone mineral density, and comorbid conditions.

Missed Dose

If you forget to take your weekly tablet, take it as soon as you remember on the morning of a following day. Then return to taking your tablet on your original scheduled day each week. Do not take two tablets on the same day to compensate for a missed dose. If you only remember close to your next scheduled dose, skip the missed dose entirely and resume your regular weekly schedule. Consistent timing maximises both safety and effectiveness.

Overdose

If You Stop Taking Optinate Septimum

Unlike some medications whose effects disappear quickly after discontinuation, bisphosphonates have a very long skeletal half-life due to their incorporation into the bone matrix. The bone protective effect of risedronate therefore declines gradually rather than abruptly. Nevertheless, bone mineral density may begin to decrease again after stopping treatment, and fracture risk may gradually rise, especially in patients with severe osteoporosis. Any decision to pause or stop treatment should be made in consultation with your doctor.

What Are the Side Effects of Optinate Septimum?

Like all medications, Optinate Septimum can cause side effects, although not everyone will experience them. The gastro-resistant formulation was developed partly to reduce upper gastrointestinal side effects compared with standard risedronate tablets, and clinical data suggest modest advantages for some GI symptoms. However, the overall safety profile is otherwise similar to that of standard risedronate. Most adverse effects are mild and transient, but a small proportion require medical attention.

Side Effects by Frequency

Adverse effects are grouped below using the standard MedDRA frequency categories used in European prescribing information.

Atypical Femoral Fractures

Atypical (non-traumatic) fractures of the proximal femoral shaft have been reported in association with long-term bisphosphonate use. These fractures are typically preceded by weeks or months of persistent thigh, hip, or groin pain and often occur bilaterally. The absolute risk is low (estimated at approximately 3–5 per 10,000 patient-years with oral bisphosphonates), and for most patients with active osteoporosis, the benefit of fracture prevention outweighs this risk. Nevertheless, any new thigh, hip, or groin pain in a patient on long-term bisphosphonate therapy warrants clinical evaluation, often including radiographic imaging of the entire femur.

Osteonecrosis of the Jaw

Osteonecrosis of the jaw is a rare complication of bisphosphonate therapy. It is typically triggered by invasive dental procedures (especially tooth extraction) in the context of underlying risk factors such as poor oral hygiene, dental infection, smoking, diabetes, or corticosteroid therapy. The estimated incidence with oral bisphosphonates used for osteoporosis is approximately 1 in 10,000 to 1 in 100,000 patient-years — far lower than with intravenous bisphosphonates used for cancer-related bone disease. Maintaining good oral hygiene, receiving regular dental examinations, and completing elective dental work (where possible) before starting therapy significantly reduces the risk.

Reassurance Context

Most people who take Optinate Septimum tolerate it well. In large randomised trials of oral bisphosphonates, discontinuation rates due to adverse events have been broadly similar between active drug and placebo in many studies. Minor gastrointestinal symptoms are the most common reason for stopping, and with the gastro-resistant formulation, these tend to be less prominent than with standard film-coated tablets in some comparative studies.

How Should You Store Optinate Septimum?

Proper storage preserves both the chemical stability and the physical integrity of the gastro-resistant coating. Optinate Septimum should be stored at controlled room temperature, generally below 25°C (77°F), in its original blister pack. Do not transfer tablets to pill organisers for more than a few days in advance, as blister packaging protects the tablets from moisture and light. Avoid storing the medication in bathrooms or kitchens, where humidity and temperature fluctuations can be significant.

Keep Optinate Septimum out of the sight and reach of children at all times. Accidental ingestion can cause significant oesophageal irritation and, at high doses, symptomatic hypocalcaemia. If accidental ingestion occurs, follow the overdose guidance in the dosage section of this guide and contact medical services immediately.

Always check the expiry date before taking any medication. The expiry date printed on the blister pack or outer carton, usually after “EXP”, refers to the last day of the month printed. Do not use Optinate Septimum after this date, as the chemical stability and therefore the effectiveness of the medication may be compromised.

Do not dispose of medications via household waste or by flushing them down the toilet. Return any unused or expired tablets to your local pharmacy for proper disposal. These measures help protect the environment and prevent accidental exposure to others.

What Does Optinate Septimum Contain?

Active Ingredient

Each gastro-resistant tablet of Optinate Septimum contains 35 mg risedronate sodium, which is equivalent to approximately 32.5 mg of risedronic acid. Risedronic acid is the pharmacologically active moiety — a pyridinyl bisphosphonate that binds with high affinity to hydroxyapatite crystals in bone tissue and selectively suppresses osteoclast activity.

Inactive Ingredients (Excipients)

The complete list of excipients varies slightly by manufacturer and jurisdiction, but for the gastro-resistant formulation typically includes:

Tablet core:

• Microcrystalline cellulose — binder and filler that provides structural integrity to the tablet.
• Crospovidone — super-disintegrant that enables rapid tablet disintegration once the enteric coating has dissolved.
• Magnesium stearate — lubricant used during tablet compression.
• Colloidal anhydrous silica — glidant that improves powder flow during manufacturing.

Gastro-resistant (enteric) coating:

• Methacrylic acid-ethyl acrylate copolymer (or similar enteric polymer) — the active functional component that prevents dissolution in the acidic stomach.
• Triethyl citrate — plasticiser that gives flexibility to the coating.
• Talc — anti-tacking agent.

Film overcoating:

• Hypromellose — film-former for easier swallowing.
• Macrogol — plasticiser for the overcoating.
• Titanium dioxide (E171) — white colouring pigment.
• Iron oxide pigments (E172) — may contribute to tablet colour depending on the product.

Appearance and Packaging

Optinate Septimum 35 mg gastro-resistant tablets are typically oval or round film-coated tablets, distinctively coloured, and often embossed or printed with an identification mark. They are supplied in PVC/PE/PVDC-aluminium blister packs, typically in pack sizes of 4, 12, or 28 tablets (representing 1, 3, or 7 months of weekly treatment). Not all pack sizes may be marketed in every country.

References

This article is based on the following peer-reviewed sources and international medical guidelines:

1. Wells GA, Cranney A, Peterson J, et al. Risedronate for the primary and secondary prevention of osteoporotic fractures in postmenopausal women. Cochrane Database of Systematic Reviews. 2008;(1):CD004523. doi:10.1002/14651858.CD004523.pub3
2. Harris ST, Watts NB, Genant HK, et al. Effects of risedronate treatment on vertebral and nonvertebral fractures in women with postmenopausal osteoporosis: a randomized controlled trial. JAMA. 1999;282(14):1344-1352. doi:10.1001/jama.282.14.1344
3. McClung MR, Geusens P, Miller PD, et al. Effect of risedronate on the risk of hip fracture in elderly women. N Engl J Med. 2001;344(5):333-340. doi:10.1056/NEJM200102013440503
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5. U.S. Food and Drug Administration (FDA). Actonel (risedronate sodium) Prescribing Information. FDA, updated 2023.
6. National Institute for Health and Care Excellence (NICE). Bisphosphonates for treating osteoporosis. NICE Technology Appraisal Guidance [TA464], updated 2023.
7. World Health Organization. WHO Model List of Essential Medicines — 23rd edition. WHO, 2023.
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9. Camacho PM, Petak SM, Binkley N, et al. American Association of Clinical Endocrinologists/American College of Endocrinology Clinical Practice Guidelines for the Diagnosis and Treatment of Postmenopausal Osteoporosis — 2020 Update. Endocr Pract. 2020;26(Suppl 1):1-46.
10. Khan AA, Morrison A, Hanley DA, et al. Diagnosis and management of osteonecrosis of the jaw: a systematic review and international consensus. J Bone Miner Res. 2015;30(1):3-23.
11. Shane E, Burr D, Abrahamsen B, et al. Atypical subtrochanteric and diaphyseal femoral fractures: second report of a task force of the American Society for Bone and Mineral Research. J Bone Miner Res. 2014;29(1):1-23.
12. Kanis JA, Cooper C, Rizzoli R, Reginster JY; European Society for Clinical and Economic Aspects of Osteoporosis (ESCEO). European guidance for the diagnosis and management of osteoporosis in postmenopausal women. Osteoporos Int. 2019;30(1):3-44.
13. British National Formulary (BNF). Risedronate Sodium. Joint Formulary Committee, updated 2025.

Editorial Team

This article has been researched, written, and medically reviewed by the iMedic Medical Editorial Team, comprising licensed specialist physicians in endocrinology, clinical pharmacology, and internal medicine. All recommendations reflect current international guidelines and peer-reviewed clinical evidence.