High Cholesterol? Learn about treatments

Midodrine Hydrochloride

Pronunciation

Pronunciation: mid-OH-drean HIGH-droe-KLOR-ide
Class: Vasopressor

Trade Names

ProAmatine
- Tablets 2.5 mg
- Tablets 5 mg
- Tablets 10 mg

Apo-Midodrine (Canada)

Pharmacology

Activates arteriolar and venous α-adrenergic receptors, resulting in an increase in vascular tone and elevation of BP.

Slideshow: Worried About Ebola? You’re More Likely to Get These 10 Serious Infections

Pharmacokinetics

Absorption

Midodrine is rapidly absorbed. Absolute bioavailability is 93%, prodrug T max is 30 min, and metabolite T max is 1 to 2 h.

Distribution

Neither prodrug nor metabolite is bound to plasma proteins to any significant extent.

Metabolism

Major active metabolite is desglymidodrine. Declycination of midodrine to desglymidodrine takes place in many tissues. Both compounds are metabolized in part by the liver.

Elimination

Renal Cl of desglymidodrine is 385 mL/min (approximately 80% by active renal secretion). The t ½ is 25 min (midodrine) and 3 to 4 h (desglymidodrine).

Peak

Time to peak is 1 h.

Duration

Duration is 2 to 3 h.

Special Populations

Renal Function Impairment

Use cautiously in patients with urinary retention problems. A lower starting dose (2.5 mg) may be necessary. Assess renal function prior to initial use.

Hepatic Function Impairment

Use with caution, as the liver has a role in the metabolism.

Indications and Usage

Treatment of symptomatic orthostatic hypotension in patients whose lives are considerably impaired despite standard clinical care, including support stockings, fluid expansion, and lifestyle changes.

Unlabeled Uses

Management of urinary incontinence.

Contraindications

Severe organic heart disease, acute renal failure, urinary retention, phenochromocytoma, thyrotoxicosis, or in patients with persistent and excessive supine hypertension.

Dosage and Administration

Adults

PO 10 mg 3 times daily during daytime hours.

Renal Function Impairment
Adults

PO Start with 2.5 mg/dose.

Storage/Stability

Store tablets at controlled room temperature (59° to 86°F).

Drug Interactions

Alpha-blocking agents (eg, prazosin, terazosin, doxazosin)

May antagonize pressor effects of midodrine.

Cardiac glycosides (ie, digitalis), beta-blockers

May precipitate bradycardia, AV block, or arrhythmia.

Fludrocortisone

May exacerbate supine hypertension.

Vasoconstrictors (eg, dihydroergotamine, ephedrine, phenylephrine, phenylpropanolamine, pseudoephedrine)

May enhance pressor effects of midodrine.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Supine and sitting hypertension (7%); bradycardia.

CNS

Paresthesia (18%); headache; confusion; nervousness; anxiety; confusion; abnormal thinking.

Dermatologic

Piloerection (13%); scalp pruritus (12%); rash (2%).

GI

Abdominal pain; dry mouth.

Genitourinary

Dysuria (frequency, impaired micturition, urinary retention, urinary urgency) (13%).

Miscellaneous

Pain, chills (5%); facial flushing; feeling of fullness/pressure in head.

Precautions

Warnings

Hypertension

Because the drug can cause significant hypertension, use only in patients whose lives are considerably impaired despite critical care. Clinical benefits have not been verified.


Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Renal Function

Use with caution. Initiate therapy with smaller doses.

Hepatic Function

Use with caution.

Bradycardia

May occur because of vagal reflex. Use caution when coadministering with other agents that can reduce heart rate (eg, cardiac glycosides, beta-blockers, psychopharmacologic agents).

Diabetes

Use with caution.

Supine hypertension

Potentially most serious adverse reaction. Most common in patients with elevated pretreatment supine systolic BP (mean, 170 mm Hg). Use is not recommended in patients with pretreatment supine systolic BP above 180 mm Hg. Monitor supine and sitting BPs.

Urinary retention

Use with caution because of effect on α-adrenergic receptors of bladder neck.

Overdosage

Symptoms

Hypertension, piloerection, sensation of coldness, urinary retention.

Patient Information

  • Advise patient to read the patient information leaflet before starting therapy and with each refill.
  • Ensure that patient understands dosing schedule and importance of taking last dose more than 4 h before bedtime to minimize supine hypertension.
  • Advise patient to take as prescribed and not to stop taking or change the dose unless advised by health care provider.
  • Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
  • Advise patient to skip dose before lying down for any length of time (eg, nap).
  • Ensure that patient has, and can use, a home BP monitoring device. Advise patient to monitor and record BP and pulse at regular intervals and in lying, sitting, and standing positions. Advise patient to inform health care provider if persistent hypertension noted or if heart rate is persistently slow.
  • Advise patient to sleep with head of bed elevated if supine hypertension noted.
  • Advise patient to discontinue therapy and notify health care provider immediately if any of the following occur: cardiac awareness, pounding in the ears, headache, blurred vision, slowing of heart rate, dizziness, fainting.
  • Advise patient that abnormal skin sensations, goosebumps, itching, and painful or difficult urination are most common adverse reactions and to inform health care provider if these or any other unexplained sensation or feeling occur and are bothersome.
  • Advise patient to inform health care provider of any unexplained feeling or sensation.

Copyright © 2009 Wolters Kluwer Health.

Hide
(web1)