Reasonable Hold Parameters for Midodrine
Midodrine should be held if the patient's supine systolic blood pressure is ≥180 mmHg or if they experience symptoms of supine hypertension such as headache, pounding in the ears, or blurred vision. 1
Dosing and Administration Guidelines
Midodrine is indicated for the treatment of symptomatic orthostatic hypotension in patients whose lives are considerably impaired despite standard non-pharmacological interventions. When prescribing midodrine, the following parameters should be observed:
Timing Parameters
- First dose: Take before arising from bed in the morning
- Last dose: No later than 6 PM or at least 4 hours before bedtime 2, 1
- Standard dosing schedule: Three times daily (morning, midday, late afternoon) 3
Blood Pressure Parameters
- Hold for supine systolic BP ≥180 mmHg 2
- Hold for sitting systolic BP ≥200 mmHg (22% of patients on 10 mg and 45% of patients on 20 mg experienced supine systolic BP ≥200 mmHg) 1
- Monitor for supine hypertension, which can persist for 6 hours or more after dosing 1
Symptom-Based Parameters
Hold midodrine if the patient experiences:
- Cardiac awareness/palpitations
- Pounding in the ears
- Headache
- Blurred vision
- Bradycardia or pulse slowing
- Increased dizziness or syncope related to bradycardia 1
Special Considerations
Renal Function
- For patients with renal impairment: Use with caution and start at a lower dose (2.5 mg) as desglymidodrine is eliminated via the kidneys 1
- For patients on hemodialysis: Be aware that midodrine is removed by dialysis 1
Concomitant Medications
Hold or use with extreme caution when combined with:
- Cardiac glycosides (digitalis) due to potential for bradycardia
- Other vasoconstrictors (phenylephrine, ephedrine, pseudoephedrine)
- MAO inhibitors or linezolid
- Alpha-adrenergic blocking agents (prazosin, terazosin, doxazosin) which can antagonize midodrine's effects 1
Duration of Action
- Peak effect: 1-2 hours after dosing
- Duration: Effects can persist for 2-3 hours after a 10 mg dose and up to 4 hours after a 20 mg dose 1, 4
- Metabolite half-life: Approximately 3-4 hours 1, 4
Clinical Pearls and Pitfalls
- Supine hypertension can persist for a prolonged period (documented up to 19 days in one pediatric case report) after discontinuation 5
- The therapeutic goal is to minimize orthostatic symptoms rather than to restore normotension 2
- Patients should be instructed to take their last daily dose 3-4 hours before bedtime to minimize nighttime supine hypertension 1
- Sleeping with the head of the bed elevated (10-15 cm) can help prevent supine hypertension 3
By following these hold parameters and monitoring guidelines, clinicians can optimize the safety and efficacy of midodrine therapy in patients with orthostatic hypotension.