- Doxycycline is the drug of choice for severe cholera because it rapidly reduces vibrio cholerae colonization and shortens the duration of diarrhea and fluid loss.
- It is effective in eradication of the organism and prevention of transmission.
- Single-dose therapy is usually sufficient, which aids compliance in outbreak settings.
- Other antibiotics like azithromycin and ciprofloxacin may be used but doxycycline remains preferred due to well-documented efficacy and low cost.
- Ampicillin is generally less effective due to resistance.
- Prompt antibiotic therapy combined with aggressive rehydration is crucial in severe cases.

Reference: Davidson’s Principles and Practice of Medicine, 24th Edition, Chapter: Infectious Diarrhea, Page 675.