Possible concentration-dependent suppression of immune response by verapamil
N. W. Tietz and J. Thompson
University of Kentucky Medical Center, Lexington, USA.
Calcium channel blockers inhibit in vitro the lymphocyte response to
mitogens and the generation of cytotoxic T-cell and natural killer cell
activity. We report on a patient taking verapamil hydrochloride who
experienced repeated, prolonged viral infections. His lymphocyte response
to phytohemagglutinin, pokeweed mitogen, and tetanus antigen were
suppressed; the mononuclear response to soluble tetanus was markedly
diminished; and there was no response to influenza vaccination. On lowering
the verapamil dose, or changing therapy to clonidine hydrochloride, all the
above-mentioned functions returned to normal and a response to influenza
vaccination was observed. We speculate that the prolonged viral infection
observed in this patient may have been caused by suppression of the immune
response by verapamil and we encourage further boad-based studies.
