Reclast (zoledronic acid) is typically given for 3 years for most people with osteoporosis, and up to 6 years for those at very high fracture risk. After that, guidelines recommend a treatment pause called a “drug holiday” to reduce the chance of rare but serious side effects. The exact number of infusions you receive depends on your fracture risk, bone density scores, and how your body responds to treatment.
Standard Treatment: 3 Years
Reclast is given as a once-yearly intravenous infusion, so 3 years of treatment means 3 total infusions. For most people with osteoporosis who haven’t had a prior fracture and whose bone density isn’t severely low, 3 years is the standard course. At that point, your doctor will reassess your fracture risk and decide whether to continue or take a break.
This 3-year benchmark comes from the HORIZON extension trial, which showed that women who received 6 annual infusions had fewer spinal fractures than those who stopped after 3. But for people who aren’t at high risk, the bone-protecting benefits of those first 3 infusions persist even after stopping, making a pause both safe and reasonable.
High-Risk Patients: Up to 6 Years
If you’re at very high fracture risk, treatment can continue for up to 6 years (6 annual infusions). You’d fall into this category if you’ve already had an osteoporotic fracture, if your hip bone density T-score is at or below negative 2.5, or if a fracture risk assessment puts you in a high-risk range. Both the American College of Obstetricians and Gynecologists and the American Association of Clinical Endocrinology support this longer timeline for people who meet these criteria.
Beyond 6 years, the evidence for continued benefit drops off. Limited data suggest that treatment past this point does not significantly reduce the likelihood of fractures outside the spine. So even for the highest-risk patients, 6 years is generally the upper boundary before a drug holiday.
What Happens During a Drug Holiday
A drug holiday doesn’t mean your bones are suddenly unprotected. Reclast binds tightly to bone and continues working long after your last infusion. Unlike some other osteoporosis treatments that lose their effect quickly once stopped, zoledronic acid’s bone-preserving effects can last for years.
For most people not at high fracture risk, a holiday of 2 to 3 years is typical after completing 3 years of infusions. During this time, your doctor will monitor your bone density and may check markers of bone turnover through blood tests. If your bone density starts declining significantly or you have a new fracture, treatment can be restarted.
Why There’s an Upper Limit
The reason for capping treatment has to do with two rare but serious complications: atypical femur fractures and osteonecrosis of the jaw. Both become more likely the longer you take bisphosphonates like Reclast.
Atypical femur fractures are unusual breaks in the thighbone that occur with minimal trauma. During the first 2 years of bisphosphonate therapy, the rate is roughly 1.78 per 100,000 patients per year. But with 8 to 10 years of continuous use, that rate climbs to about 113 per 100,000 per year. Most studies show the risk rises noticeably after 3 years of use and continues climbing with each additional year. These fractures are still rare in absolute terms, but they’re serious enough that limiting treatment duration makes sense for people who can safely pause.
Osteonecrosis of the jaw, where bone tissue in the jaw deteriorates, is also linked to prolonged bisphosphonate use, though it’s more common at the higher doses used in cancer treatment than at the osteoporosis dose.
Reclast for Paget’s Disease
If you’re receiving Reclast for Paget’s disease rather than osteoporosis, the protocol is different. A single 5 mg infusion can produce an extended remission period. There’s no fixed schedule of annual infusions. Instead, retreatment is considered only if blood tests show the disease is becoming active again, specifically if a marker called serum alkaline phosphatase rises or never normalized after the first dose, or if symptoms return. Some people with Paget’s disease go years between infusions.
Kidney Function Can Change the Timeline
Regardless of how many years you’ve been on Reclast, kidney function plays a role in whether you can continue. Reclast is cleared through the kidneys, and it’s contraindicated in people with severely reduced kidney function. Before each infusion, your doctor should check your kidney function. If your kidneys have declined significantly since your last infusion, treatment may need to stop even if you haven’t reached the 3- or 6-year mark. Staying well hydrated before and after each infusion helps reduce kidney stress.
Restarting After a Holiday
A drug holiday isn’t necessarily permanent. If your fracture risk increases again, whether from declining bone density, aging, a new fracture, or starting medications that weaken bones (like corticosteroids), your doctor may restart Reclast. The guidelines don’t set a firm lifetime cap on total years of use, but they do emphasize reassessing risk at each decision point rather than continuing indefinitely on autopilot. The pattern for most people is cycles of treatment followed by monitored breaks, with the goal of keeping fracture risk low while minimizing long-term side effects.