From the Guidelines
Midodrine typically starts working within 1 hour of taking it, with peak effects occurring around 2-3 hours after ingestion, as supported by its mechanism of action and clinical use 1. The effects of midodrine are temporary, lasting about 2-4 hours per dose, which is why multiple daily doses are necessary to maintain its blood pressure-raising effects throughout the day. For optimal results, midodrine is usually taken three times daily, with doses spaced about 3-4 hours apart. The last dose should be taken at least 4 hours before bedtime to avoid supine hypertension, a common adverse effect of midodrine 1. A common starting dose is 2.5 mg to 10 mg three times daily, which may be increased as needed and tolerated, with the goal of minimizing postural symptoms rather than restoring normotension 1. Midodrine works by stimulating alpha-1 adrenergic receptors, which causes constriction of blood vessels and increases blood pressure, making it a useful addition to the first-line treatment in patients with chronic autonomic nervous system dysfunction 1. Key points to consider when prescribing midodrine include:
- Starting with a low dose and titrating as needed and tolerated
- Avoiding doses close to bedtime to prevent supine hypertension
- Monitoring for adverse effects, such as pilomotor reactions, pruritus, and urinary retention
- Educating patients on the temporary nature of midodrine's effects and the need for multiple daily doses. Overall, midodrine is a useful medication for the treatment of symptomatic orthostatic hypotension, with a rapid onset of action and relatively short duration of effect, as supported by the highest quality evidence available 1.
From the FDA Drug Label
Standing systolic blood pressure is elevated by approximately 15 to 30 mmHg at 1 hour after a 10 mg dose of midodrine, with some effect persisting for 2 to 3 hours. The plasma levels of the prodrug peak after about half an hour, and decline with a half-life of approximately 25 minutes, while the metabolite reaches peak blood concentrations about 1 to 2 hours after a dose of midodrine and has a half-life of about 3 to 4 hours.
Midodrine starts to work within 1 hour of administration, with peak effects on standing systolic blood pressure observed at this time. The effects of midodrine persist for 2 to 3 hours after a single dose. The active metabolite, desglymidodrine, reaches peak blood concentrations 1 to 2 hours after a dose of midodrine 2.
From the Research
Time to Take Effect
- The time it takes for midodrine to work is not explicitly stated in the provided studies, but its effects can be observed within a few hours of administration 3, 4, 5, 6.
- In one study, midodrine decreased both supine and upright heart rate at 2 hours after administration 5.
- Another study found that midodrine increased mean arterial pressure and systemic vascular resistance, and decreased heart rate, within the first 3 hours after administration 6.
- The effects of midodrine on renal hemodynamics and function were also observed within 3-6 hours after administration 6.
Onset of Action
- The onset of action of midodrine can be inferred to be within 1-3 hours based on the observed effects on blood pressure, heart rate, and renal function 3, 4, 5, 6.
- However, the exact time to reach peak effect is not specified in the provided studies.
Duration of Action
- The duration of action of midodrine is not explicitly stated, but its effects can last for several hours based on the observed changes in blood pressure, heart rate, and renal function 3, 4, 5, 6.
- One study found that the effects of midodrine on systemic hemodynamics were maintained during the 3- to 6-hour period after administration 6.