Other side effects reported in post-marketing trials include:
- allergic reaction,
- chest pain,
- low blood pressure,
- gynecomastia (enlargement of mens' breasts, bradycardia [slow heartbeat]),
- difficulty sleeping,
- vasculitis, and
- eye pain.
GENERIC AVAILABLE: Yes
PREPARATIONS: Oral capsules: 1, 2, and 5 mg.
STORAGE: Capsules should be stored at room temperature, between 59 F and 86 F (15 C and 30 C).
- The dose of prazosin should be adjusted based on the individual patient response.
- For the treatment of high blood pressure: Most patients are started with 1 mg by mouth 2-3 times a day. To decrease the risk of orthostatic hypotension the first dose may be given at bedtime. Orthostatic hypotension is a drop in blood pressure when standing up from a sitting or lying position. Dosage may be increased gradually over time to a total daily dose of 20 mg given in multiple doses.
- If adding another blood pressure lowering agent or water pill (diuretic) to prazosin therapy, the dose of prazosin should be reduced to 1-2 mg by mouth three times a day, followed by slow increases in dose as needed.
- As elderly patients are more sensitive to the side effects of low blood pressure, dose reduction in the elderly is necessary. Most elderly patients are started on 1 mg by mouth 1-2 times daily.
- The safety and effectiveness of prazosin in children has not been established.
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