Drug-induced hypochlorhydria causes high duodenal bacterial counts in the elderly.
BACKGROUND
Small bowel bacterial overgrowth secondary to drug-induced hypochlorhydria may be of particular importance in the elderly, in whom anti-ulcer drugs are commonly prescribed and the consequences of malabsorption may be severe.


METHODS
Duodenal aspirates were obtained from elderly individuals before (n = 24) and during a 2-month treatment course with either omeprazole (20 mg daily; n = 8) or ranitidine (300 mg b.d.; n = 6), and from six patients with small bowel bacterial overgrowth who had diarrhoea and malabsorption.


RESULTS
Before treatment, duodenal bacterial counts were normal (< 10(4) colony forming units/mL) in 23 elderly subjects (96%). However, six of 14 patients (43%) treated with omeprazole (5 of 8) or ranitidine (1 of 6) developed bacterial counts > 10(5) cfu/mL. All remained asymptomatic and had normal lactulose breath H2 profiles during treatment.


CONCLUSIONS
Drug-induced hypochlorhydria causes high duodenal bacterial counts in the elderly but, in the short term, this bacterial overgrowth is not associated with malabsorption.
Gastroenterology Unit, Guy's Hospital Campus, Division of Medicine, UMDS, London, UK.
S P
SP
Pereira
N
N
Gainsborough
R H
RH
Dowling
D000126:Achlorhydria / Q000139:chemically induced* / Q000503:physiopathology; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D001420:Bacteria, Aerobic / Q000187:drug effects / Q000254:growth & development*; D001421:Bacteria, Anaerobic / Q000187:drug effects / Q000254:growth & development*; D015169:Colony Count, Microbial; D004386:Duodenum / Q000382:microbiology* / Q000473:pathology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption / Q000187:drug effects / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D011899:Ranitidine / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use
D000897:Anti-Ulcer Agents; D011899:Ranitidine; D009853:Omeprazole