Interactions between rabavert-obsolete(rabies vaccine (obsolete)) and Aralen phosphate (chloroquine)
chloroquine and rabies vaccine (obsolete) (Moderate Drug-Drug)
ADJUST DOSING INTERVAL: Chloroquine may reduce the antibody response to primary immunization with rabies vaccine. The mechanism may involve impairment of macrophage lysosomal enzyme functions such that there is interference with antigen-processing mechanisms of the macrophage, which would then affect recognition of antigen by T cells and, ultimately, activation of B cells and antibody production. Chloroquine prophylaxis given for more than 4 weeks during the vaccination period has been associated with poor antibody response to intradermal human diploid-cell rabies vaccine in Peace Corps volunteers. Also, in a study of healthy volunteers who were not previously vaccinated against rabies, 26 subjects who received chloroquine (300 mg/week beginning nine days before the first dose of vaccine and continuing until day 48) concomitantly with human diploid-cell rabies vaccine (0.1 mL intradermally on days 0, 7, and 28) had a significantly lower mean rabies-neutralizing antibody titer on each day of testing (day 28, day 49, and day 108) than 25 controls who received the vaccine without chloroquine. However, both groups had neutralizing antibody titers on days 49 and 105, according to the criteria of the Centers for Disease Control and Prevention. The blood concentrations of chloroquine and its pharmacologically active metabolite, desethylchloroquine, were negatively associated with log antibody titers.
MANAGEMENT: To ensure adequate antibody response, pre-exposure immunization with human diploid-cell rabies vaccine should be administered before initiating chloroquine treatment. The same precaution may be applicable to purified chick embryo cell-derived rabies vaccine, although clinical data are lacking.
