Rimantadine hydrochloride is an RNA synthesis inhibitor that is used as an antiviral agent in the prophylaxis and treatment of influenza.

In a variety of tissue culture systems, rimantadine (25 μg/ml) completely suppressed the growth of dengue virus type 2 in human peripheral blood leukocytes (PBL). Rimantadine significantly inhibited dengue virus replication in cultures of rhesus monkey PBL. In virus-infected LLC-MK2 cell cultures, rimantadine decreased the production of all four types of dengue virus [1]. Rimantadine interfered with the generation of cellular immune responses. Rimantadine hydrochloride inhibited the proliferative response of human peripheral blood lymphocytes to mitogenic and antigenic stimulation. Rimantadine hydrochloride (25 μg/ml) suppressed the responses to phytohemagglutinin, pokeweed mitogen, and concanavalin A by 25, 65, and 90%, respectively. rimantadine (10 μg/ml) significantly inhibited responses to streptokinase-streptodornase, tetanus toxoid, and A2/Aichi influenza vaccine [2]. In a randomized, double-blind trial involving patients with uncomplicated influenza A H3N2 subtype virus infection, rimantadine (200 mg/day for 5 days) significantly reduced nasal secretion viral titers (days 2 through 4), maximal temperature (days 2 and 3), time until defervescence (mean, 37 h shorter), and systemic symptoms [3].

References:
[1] Koff W C, Elm Jr J L, Halstead S B.  Suppression of dengue virus replication in vitro by rimantadine hydrochloride[J]. The American journal of tropical medicine and hygiene, 1981, 30(1): 184-189.
[2] Koff W C, Peavy D L, Knight V.  Inhibition of in vitro proliferative responses of human lymphocytes by rimantadine hydrochloride[J]. Infection and immunity, 1979, 23(3): 665-669.
[3] Hayden F G, Monto A S.  Oral rimantadine hydrochloride therapy of influenza A virus H3N2 subtype infection in adults[J]. Antimicrobial agents and chemotherapy, 1986, 29(2): 339-341.