Hypertension Drug Causes Rare, but Serious Side Effect

While the incidence of drug-induced agranulocytosis (DIAG) has remained stable over the past 20 years, an accurate estimation of incidence may be difficult to make given the side effect is frequently underreported. Currently, there is no gold standard test for diagnosing DIAG, therefore increased awareness among clinicians about this rare but potentially lethal adverse effect is warranted. This report, published in the American Journal of Case Reports, describes a case of DIAG associated with a commonly used antihypertensive medication.

The patient, a 61-year-old male, presented to the emergency department with throat pain and swallowing difficulties which he reported lasting one week; his medical history included hypertension and he denied smoking or recreational drug use as well as any recent travel, weight loss or night sweats. His medications included amlodipine and benazepril. Full work-up of the patient revealed the following:

• Temperature: 102º F
• Vital signs: normal
• Pulmonary exam: good bilateral air entry, no added rhonchi or wheezing
• Cardiovascular exam: no abnormalities
• Neurological exam: no abnormalities
• Abdominal exam: soft, non-tender, no palpable visceromegaly
• CBC: white blood cell count 0.5K/μL, absolute neutrophil count: 0, hemoglobin: normal, hematocrit: mildly decreased, platelet count: normal

A diagnosis of febrile neutropenia was made and the patient was admitted to the hospital for further investigation and management. In the hospital, broad-spectrum antibiotics for pharyngitis and suspected pharyngeal abscess were initiated and further testing was done to rule out possible infection. Tests for malaria, Epstein-Barr virus, HIV, ANA, RPR, IgM, hepatitis B and C were negative, however a test for hepatitis A total antibody was positive. All cultures (blood, throat, blood fungal, acid-fast bacillus, urine) were found to be negative; urine toxicology screen was negative as well. Apart from a decrease in albumin, serum proteins were within normal ranges; neutrophil antibodies were not detected. Vitamins, LDH, and folate were at normal levels, however ferritin was elevated to 627.8ng/mL. Imaging of chest, abdomen, head and neck showed no abnormalities; cerebrospinal fluid was tested for bacterial or viral pathogens but results were negative and cell counts, protein and glucose levels were all within normal limits.