Indications/Uses
Orthostatic hypotension
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Dosage/Direction for Use
Adult : PO Initial: 2.5 mg 2-3 times/day, adjust as needed, up to 10 mg tid.
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Dosage Details
Oral
Orthostatic hypotension Adult: Initially, 2.5 mg 2-3 times daily, adjusted gradually according to response at weekly intervals, up to 10 mg tid. Last dose of the day should not be taken after evening meal or <4 hr before bedtime to reduce potential for supine HTN.
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Renal Impairment
Initially, 2.5 mg 2-3 times daily, gradually increased as tolerated.
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Administration
Should be taken with food.
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Contraindications
Severe organic heart disease (e.g. bradycardia, ischaemic heart disease, CHF), acute renal failure, urinary retention, phaeochromocytoma, thyrotoxicosis, persistent and excessive supine HTN.
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Special Precautions
Patient w/ DM, history of visual problems (esp when taken w/ fludrocortisone). Hepatic and renal impairment. Pregnancy and lactation.
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Adverse Reactions
Supine and sitting HTN, bradycardia, paraesthesia, pilomotor reaction, chills, pruritus, rash; urinary urge, urinary retention, urinary frequency; headache, fullness in the head, vasodilation, flushing face, confusion, dry mouth, anxiety. Rarely, visual field defect, dizziness, skin hyperaesthesia, insomnia, somnolence, erythema multiforme, canker sore, dry skin; dysuria, impaired urination, asthenia, backache, pyrosis, GI distress, flatulence, leg cramps.
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MonitoringParameters
Monitor supine and sitting BP; hepatic and renal function.
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Overdosage
Symptoms: HTN, piloerection, coldness, urinary retention. Management: Induce emesis. Admin of α-sympatholytic drugs (e.g. phentolamine) may be beneficial.
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Drug Interactions
Enhanced pressor effects w/ α-adrenergic agonists (e.g. phenylephrine, ephedrine, dihydroergotamine, phenylpropanolamine, pseudoephedrine). Reduced effect w/ α-adrenergic blockers (e.g. prazosin, terazosin, doxazosin). May precipitate bradycardia, AV block, or arrhythmia w/ cardiac glycosides.
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Action
Description: Midodrine, a direct-acting sympathomimetic amine, is a prodrug which forms an active metabolite, desglymidodrine. It selectively activates the α1-adrenergic receptors of the arteriolar and venous vasculature, producing peripheral vasoconstriction and elevation of BP.
Onset: Approx 1 hr. Duration: 2-3 hr. Pharmacokinetics: Absorption: Well absorbed from the GI tract. Bioavailability: 93% (desglymidodrine). Time to peak plasma concentration: 30 min (midodrine); 1-2 hr (desglymidodrine). Distribution: Poorly crosses the blood brain barrier. Plasma protein binding: <30%. Metabolism: Metabolised in the liver and other tissues. Undergoes rapid deglycination into its active metabolite, desglymidodrine. Excretion: Via urine (80% as desglymidodrine). Elimination half-life: 25 min (midodrine); approx 3-4 hr (desglymidodrine). |
Chemical Structure
![]() Source: National Center for Biotechnology Information. PubChem Database. Midodrine, CID=4195, https://pubchem.ncbi.nlm.nih.gov/compound/Midodrine (accessed on Jan. 22, 2020) |
Storage
Store between 20-25˚C. Protect from light and moisture.
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MIMS Class
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ATC Classification
C01CA17 - midodrine ; Belongs to the class of adrenergic and dopaminergic cardiac stimulants excluding glycosides. Used in the treatment of hypotension.
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References
Anon. Midodrine . Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 21/07/2016. Buckingham R (ed). Midodrine Hydrochloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 21/07/2016. Douglas Pharmaceuticals Ltd. Gutron Tablets data sheet 03 February 2015. Medsafe. http://www.medsafe.govt.nz/. Accessed 21/07/2016. Joint Formulary Committee. Midodrine Hydrochloride. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com
. Accessed 21/07/2016. McEvoy GK, Snow EK, Miller J et al (eds). Midodrine Hydrochloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 21/07/2016. Midodrine Hydrochloride Tablet (Eon Labs, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 21/07/2016.
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