Reclast (Zoledronic Acid) Travel & Timezone-Shift Protocols

Does a timezone shift change anything about Reclast?

No. Reclast is given as a 5 mg infusion in a clinic: once a year for treating osteoporosis, once every 2 years for preventing postmenopausal osteoporosis, and as a single infusion for Paget's disease [1]. Unlike a pill taken every morning, there is no daily or weekly dose to re-time after a flight.

Zoledronic acid is not metabolized. It is excreted into the urine as the intact drug, with a terminal elimination half-life the label gives as 146 hours and plasma concentrations that fall below 1% of peak within 24 hours of the infusion [1]. Those pharmacokinetic data come from cancer patients; the label notes that pharmacokinetics were not studied in osteoporosis or Paget's disease [1].

The kidney check

Reclast is cleared by the kidney, and renal risk sits at the center of its warnings [1]. Acute renal failure has been observed after a single dose, with rare reports of hospitalization, dialysis or fatal outcome in patients who had moderate to severe renal impairment or risk factors such as advanced age, dehydration, diuretics or nephrotoxic drugs including NSAIDs [1].

The label says [1]:

• Creatinine clearance is to be calculated with the Cockcroft-Gault formula using actual body weight before each Reclast dose.
• Reclast is contraindicated when creatinine clearance is below 35 mL/min or there is evidence of acute renal impairment.
• Patients must be appropriately hydrated before the infusion. If history or physical signs suggest dehydration, Reclast is to be withheld until normovolemic status is achieved. Elderly patients and those on diuretics are at higher risk of acute renal failure and are to have fluid status assessed and be appropriately hydrated first.

The label states the hydration requirement as adequately hydrated and normovolemic, without giving a fluid volume or a number of hours [1].

The label also advises caution with potentially nephrotoxic drugs such as NSAIDs, and notes that loop diuretics may increase the risk of hypocalcemia [1]. For balance: in the 3-year osteoporosis trial, a transient creatinine rise within 10 days occurred in 1.8% of patients on Reclast versus 0.8% on placebo, and overall renal function changes were comparable to placebo [1].

Timing the annual dose around a trip

The label's osteoporosis regimen is 5 mg once a year, and a single dose should not exceed 5 mg [1]. Whether to move a dose to fit a trip is a scheduling decision for the prescriber.

The trial data show how slowly things change when dosing stops. In the HORIZON-PFT extension, 1,233 women who had already received three annual doses were randomized to three more years of zoledronic acid (n=616) or to placebo (n=617). Over years 3 to 6, femoral neck bone mineral density stayed level in the continued group and dropped slightly in the group switched to placebo, a between-group difference of 1.04%, but stayed above pretreatment levels. New morphometric vertebral fractures were 14 with continued treatment versus 30 after switching (odds ratio 0.51); other fractures did not differ [3]. The authors concluded that after three annual doses many patients may discontinue for up to three years, while those at high fracture risk, particularly for vertebral fracture, may benefit from continuing [3].

The American Society for Bone and Mineral Research task force reached a similar place: after three years of intravenous bisphosphonate, reassess risk; women not at high fracture risk after 3 to 5 years can consider a drug holiday of 2 to 3 years, while high-risk women can continue for up to 6 years with periodic evaluation [4]. The Reclast label itself says the optimal duration has not been determined and that low-fracture-risk patients should be considered for discontinuation after 3 to 5 years [1].

Post-infusion symptoms and a flight afterward

The predictable post-infusion event is the acute phase reaction. In the 7,736-woman osteoporosis trial, fever occurred in 18%, myalgia in 9%, flu-like symptoms in 8%, headache in 7% and arthralgia in 7%. Most symptoms occurred within the first three days and usually resolved within three days, though some lasted up to 7 to 14 days; symptoms decrease with later doses [1].

The label says that giving acetaminophen after Reclast may reduce the incidence of acute-phase reaction symptoms [1]. In the hip-fracture trial, where patients received acetaminophen at the time of infusion and for 72 hours afterward, fever was 7% and arthralgia 3% [1].

Arranging an infusion away from home: the 5 mg versus 4 mg check

Both Reclast and Zometa contain zoledronic acid, but they are different products with different doses and uses: Reclast 5 mg once yearly (or every 2 years, or once for Paget's disease) and the 4 mg product every 3 to 4 weeks for cancer-related bone disease [1][2]. The Reclast label says a patient being treated with Zometa should not be treated with Reclast, and the 4 mg label says the reverse [1][2].

The 4 mg regimen is for hypercalcemia of malignancy and for multiple myeloma or documented bone metastases from solid tumors alongside antineoplastic therapy. It is dose-reduced by kidney function: 3.5 mg for creatinine clearance 50 to 60 mL/min, 3.3 mg for 40 to 49, and 3.0 mg for 30 to 39 [2].

Reclast is the 5 mg product. The label specifies an infusion lasting at least 15 minutes, followed by a 10 mL normal saline flush [1]. The 4 mg cancer product is not a substitute for it [1][2].

Calcium and vitamin D

The Reclast label says osteoporosis patients should average at least 1,200 mg calcium and 800 to 1,000 international units of vitamin D daily, supplementing if diet falls short [1]. For Paget's disease the label specifies 1,500 mg elemental calcium daily in divided doses and 800 international units of vitamin D, especially in the two weeks after the infusion [1].