Cimetidine as an immunomodulator in the treatment of herpes zoster

Histamine-2 receptor antagonists as immunomodulators: new therapeutic views?

Considerable evidence has emerged to suggest that histamine participates in the regulation of the inflammatory response, immune reaction, coagulation cascade, and cardiovascular function. Furthermore, histamine may play a major role in the growth of normal and malignant tissue as a regulator of proliferation and angiogenesis. Specific histamine receptors have been identified on the surface of bone marrow cells, immune competent cells, endothelial cells, fibroblasts, and also on malignant cells. This has prompted research in regulation by specific histamine receptor agonists and antagonists. Results from such studies are currently accumulating and suggest that the histamine-2 receptor antagonists have potential beneficial effects in the treatment of certain malignant, autoimmune and skin diseases, either alone or in combination with other drugs. The beneficial effect of histamine-2 receptor antagonists as adjuvant single drugs to reduce trauma-, blood transfusion- and sepsis-induced immunosuppression has led to research in combined treatment regimens in major surgery, particularly, of patients operated on for malignant diseases.

Recognition and treatment of shingles

Varicella zoster virus (VZV) is responsible for a primary infection (varicella) followed by a latency, eventually resulting in herpes zoster (shingles). The replication cycle of VZV is normally interrupted after varicella. Consequently, VZV remains dormant in the organism. Reactivation occurs after viraemia, and the development of tissue alterations (skin and viscera) depends on the immunological status of the patient. Diagnosis of herpes zoster relies on clinical recognition and cytological and histological evaluations combined with immunohistochemistry and molecular biology techniques. Treatment of herpes zoster primarily relies upon antiviral drugs and incidentally on immunomodulating agents, specific immunoglobulins, antimicrobial agents, antiviral enzymes and corticosteroids. Drugs with a clinically relevant activity against varicella zoster virus infections include aciclovir, adenosine monophosphate, bromodeoxyuridine, desciclovir, fiacitabine, idoxuridine, interferon-alpha and vidarabine. Among them, aciclovir appears to be a first-line agent. Its efficacy has been well established by many clinical studies. Promising drugs for the future include famciclovir, penciclovir, valaciclovir and other molecules currently under investigation. Recent and promising improvements in antiviral drug development may increase patient compliance, cost-benefit ratios and therapeutic efficacy.