Safety and prophylactic efficacy of low-dose rimantadine in adults during an influenza A epidemic

Abstract

A placebo-controlled, double-blind study to evaluate the safety and prophylactic efficacy of a low dose (100 mg) of rimantadine hydrochloride against naturally occurring influenza in adults was conducted at two sites. After the onset of the influenza season, volunteers (ages, 18 to 55 years) were assigned randomly to receive rimantadine or placebo daily. Subjects were monitored for adverse effects and evidence of influenza virus infection weekly for six weeks. Only 10 (8.7%) of 114 rimantadine recipients and 5 (4.4%) of 114 placebo control recipients reported one or more mild to moderate adverse symptoms, most of which were related to the gastrointestinal or central nervous system. Compared with placebo, low-dose rimantadine was highly effective in the prevention of influenza A virus infection (20 of 110 versus 7 of 112 participants; P < 0.01) and influenza illness (7 of 110 versus of 112 participants; P = 0.04). Influenza A/Leningrad/87-like (H3N2) virus was recovered from the nasopharynxes of only five placebo recipients. These findings indicate that low-dose rimantadine is well tolerated and highly effective for the prevention of influenza A illness in healthy adults.

Influenza and the Vocal Performer: Update on Prevention and Treatment

“…In fact, there is evidence that the protective effects of amantadine and vaccine are additive. [11][12][13] Amantadine may also be used in situations where a performer has had a known contact with an affected individual. For prophylaxis, amantadine or rimantidine should be administered promptly after a sick contact and must be continued for the duration of the local outbreak.…”

The pathogenesis and management of influenza virus infection in organ transplant recipients

“…Although the use of a rapid diagnostic test is not necessary for initiating antiviral drug therapy in typical cases of influenza, it will permit physicians to withhold antibiotics and will provide reassurance that such therapy is appropriate. Treatment with antiviral therapy against influenza in organ transplant recipients should probably not exceed 10–14 days (36–39).…”

“…The M2 matrix protein inhibitors amantadine and rimantadine are related antiviral drugs with similar mechanism of action, but are effective against influenza A only. They have an efficacy of about 75–90% and their protection may be additive to that of the inactivated influenza vaccine (36–38). However, data of the effectiveness of these drugs in organ transplant recipients are lacking.…”

Use of Antivirals in Influenza in the Elderly: Prophylaxis and Therapy

“…Protection has been demonstrated in placebo-controlled studies in adults and children in open populations and in institutions when amantadine has been prescribed for 'seasonal' prophylaxis, but variable results have been obtained when the drug has been given for both prophylaxis and treatment in households or in a residential care setting. The representative studies listed in table 1 [20,23,24,[31][32][33][34] show that 'sea sonal' prophylaxis is somewhat more effective in preventing influenza-like illness (-90% ) than infection (-74% ). This distinction may be desirable, since subclinical infection could confer immunity against reinfection.…”