I read a comprehensive review article for bisphosphonates usage in clinical practices, published in 2008. Many principles would apply to Reclast or zolendronate acid. Below is an excerpt for anyone interested - it described the rational behind antihistamine use, antipyretic (acetaminophen or Tylenol) use or sometimes corticosteroid use in combat of acute inflammatory response as a result of bp treatment:

“Acute Inflammatory Response
Approximately 10% to 30% of patients receiving their first nitrogen-containing bisphosphonate infusion will experience an acute phase reaction, most commonly characterized by transient pyrexia with associated myalgias, arthralgias, headaches, and influenza-like symptoms. This rate declines by more than half with each subsequent infusion, such that a rate of 2.8% was found after the third infusion in the HORIZON trial.14 The acute phase response is believed to be the result of proinflammatory cytokine production by peripheral blood γδ T cells.132 Pretreatment with histamine receptor antagonists or antipyretics can reduce the incidence and severity of symptoms among susceptible patients. Occasionally corticosteroids are of benefit.

A relatively rare adverse effect of bisphosphonate therapy of which physicians should be aware is ocular inflammation (conjunctivitis, uveitis, episcleritis, and scleritis). This complication has been found to occur with both oral and IV bisphosphonate therapy. In the largest retrospective study to date, an incidence of approximately 0.1% was found in patients treated with oral risedronate.133 Fortunately, ocular symptoms usually resolve within a few weeks after bisphosphonate discontinuation.

Severe Musculoskeletal Pain
Although all oral and IV bisphosphonate preparations list musculoskeletal pain as a potential adverse effect in their prescribing information, the US FDA recently issued an alert highlighting the possibility of severe, incapacitating musculoskeletal pain that can occur at any point after initiation of bisphosphonate therapy.134 This severe musculoskeletal pain was distinct from the acute phase response described previously. Fewer than 120 cases had been reported by late 2002 for alendronate and mid-2003 for risedronate in total.135 At this time, both risk factors for and incidence of this adverse effect are unknown.”