Acute phase reaction
Also called: flu-like symptoms after Reclast, post-infusion reaction
What it means
An acute phase reaction is a temporary flu-like response the body has to certain medications, most commonly after the first IV infusion of a bisphosphonate like zoledronic acid (Reclast).
Knowing this is a common, usually harmless reaction can ease worry if you feel achy or feverish after a bone-strengthening infusion.
An acute phase reaction is a short-term immune response. When certain drugs enter the bloodstream, immune cells recognize them and release signaling chemicals called cytokines. These cytokines cause inflammation-like symptoms even though there's no infection. The body is simply reacting to the medication, not getting sick.
This reaction is especially common after the first IV infusion of zoledronic acid (Reclast), and can also occur with other bisphosphonates. Symptoms usually include fever, muscle aches, joint pain, fatigue, chills, and headache, starting within a day or so of the infusion. For most people, this is much milder or absent with repeat doses.
Symptoms typically resolve on their own within a few days. Your doctor can advise on appropriate ways to manage discomfort and whether future infusions need any adjustments. This reaction isn't a sign of allergy or a reason to assume the medication isn't working, but any concerning or prolonged symptoms should be discussed with your prescriber.
Feeling achy or feverish after a yearly bone infusion is usually a harmless, temporary reaction.
Where this leads
WordCurious about the drug behind that reaction? See how this once-yearly infusion works to slow bone breakdown.
Related words
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Zoledronic acid is a bisphosphonate drug given as a once-yearly IV infusion to slow bone breakdown and reduce…
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Ibandronate is a bisphosphonate drug, sold as Boniva, used to treat osteoporosis by slowing the breakdown of bone.
Cytokines are signaling proteins from immune cells; some, like TNF-alpha, IL-1 and IL-6, promote inflammation and…
A dosing schedule is how often an osteoporosis medicine is taken or given—daily, weekly, monthly, or once a…
Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
