Reclast is given once a year as a single intravenous infusion. Each dose is 5 mg, delivered through an IV over at least 15 minutes. This once-yearly schedule applies whether you’re being treated for osteoporosis or trying to prevent it.
Dosing Schedule by Condition
For osteoporosis treatment in postmenopausal women, men, and people who’ve had a low-trauma hip fracture, the standard regimen is one 5 mg infusion per year. The same dose and frequency apply to osteoporosis prevention in postmenopausal women. Unlike daily or weekly oral bisphosphonate pills, Reclast requires just one appointment per year, which is a significant part of its appeal for people who have trouble sticking to a daily medication routine or who experience stomach issues with oral options.
For Paget’s disease of bone, the initial treatment is also a single 5 mg infusion. However, retreatment isn’t automatically scheduled annually. Because the drug’s effects can last well beyond a year in Paget’s disease, additional doses are given only if the disease reactivates, based on blood markers and symptoms.
How the Infusion Works
Reclast is delivered through a vein, typically in your arm, at a doctor’s office or infusion center. The infusion itself takes a minimum of 15 minutes, though the total visit is longer once you account for setup and a brief observation period afterward. The medication comes premixed in a 100 mL solution, so there’s no complicated preparation on your end.
Before your infusion, you’ll need adequate hydration and healthy calcium and vitamin D levels. Low calcium in the blood is a risk with this type of medication, so your provider will typically check bloodwork beforehand. You should also be drinking plenty of water in the hours leading up to your appointment.
Kidney Function Requirements
Reclast is not safe for everyone. It’s contraindicated if your creatinine clearance (a measure of kidney function) is below 35 mL/min. Your provider will check kidney function before each infusion. People with evidence of acute kidney problems also cannot receive it. This is one of the key safety checks that happens at every annual visit before you get the green light for your next dose.
How Long You Stay on Reclast
You won’t necessarily receive Reclast indefinitely. The Endocrine Society recommends reassessing fracture risk after 3 years of annual IV zoledronic acid (Reclast’s active ingredient). That’s a shorter reassessment window than for oral bisphosphonates, which are typically reviewed at 5 years. The reason: research shows Reclast’s bone-protective effects persist even after you stop, so three annual infusions can provide residual benefit.
At the 3-year mark, your provider will evaluate whether you still need active treatment. If you remain at high risk for fractures, you’ll continue annual infusions. If your risk has dropped to low or moderate, you may be a candidate for a “drug holiday,” a planned break from the medication that can last up to 5 years depending on your bone density and overall risk profile.
During a drug holiday, you’re not simply forgotten. Fracture risk should be reassessed every 2 to 4 years, and a bone density scan is generally recommended 2 to 3 years after pausing Reclast. If your bone density drops significantly, you have a new fracture, or your risk profile changes, treatment can restart before the full holiday period is up.
How Effective Is One Infusion Per Year?
The once-yearly schedule is backed by strong fracture-reduction data. In clinical trials, even a single infusion of Reclast reduced the risk of new spinal fractures visible on imaging by 68% compared to placebo over three years. The overall risk of any clinical fracture dropped by 32% with just that one dose. These numbers came from patients who received only one infusion and were then followed for three years, which speaks to how long the drug remains active in bone tissue.
Reclast works by slowing down the cells that break down bone. Because it binds tightly to bone mineral and stays there for years, a single annual dose is enough to maintain its effects continuously. This long residence time in bone is also why the drug’s benefits don’t vanish the moment you stop taking it, and why drug holidays are a realistic option after a few years of treatment.