Overview
DESCRIPTION Name: Midodrine hydrochloride tablets, USP Dosage Form: 2.5 mg, 5 mg and 10 mg tablets for oral administration Active Ingredient: Midodrine hydrochloride, USP 2.5 mg, 5 mg and 10 mg Inactive Ingredients: Microcrystalline cellulose, crospovidone, hydroxypropyl cellulose, colloidal silicon dioxide and magnesium stearate.
Mechanism of Action
CLINICAL PHARMACOLOGY Mechanism of Action: Midodrine forms an active metabolite, desglymidodrine, that is an alpha 1 -agonist, and exerts its actions via activation of the alpha-adrenergic receptors of the arteriolar and venous vasculature, producing an increase in vascular tone and elevation of blood pressure. Desglymidodrine does not stimulate cardiac beta-adrenergic receptors. Desglymidodrine diffuses poorly across the blood-brain barrier, and is therefore not associated with effects on the central nervous system. Administration of midodrine results in a rise in standing, sitting, and supine systolic and diastolic blood pressure in patients with orthostatic hypotension of various etiologies.
Indications
- INDICATIONS AND USAGE Midodrine hydrochloride tablets are indicated for the treatment of symptomatic orthostatic hypotension (OH). Because midodrine hydrochloride tablets can cause marked elevation of supine blood pressure (BP>200 mmHg systolic), it should be used in patients whose lives are considerably impaired despite standard clinical care, including non-pharmacologic treatment (such as support stockings), fluid expansion, and lifestyle alterations.
Common Doses
- 10 mg
- 20 mg
- 30 mg
- 2.5 mg
Dosage
DOSAGE AND ADMINISTRATION The recommended dose of midodrine hydrochloride tablet is 10 mg, 3 times daily. Dosing should take place during the daytime hours when the patient needs to be upright, pursuing the activities of daily living. A suggested dosing schedule of approximately 4-hour intervals is as follows: shortly before, or upon arising in the morning, midday and late afternoon (not later than 6 P.M.). Doses may be given in 3-hour intervals, if required, to control symptoms, but not more frequently.
Black Box Warning
Warning: Because midodrine can cause marked elevation of supine blood pressure, it should be used in patients whose lives are considerably impaired despite standard clinical care. The indication for use of midodrine in the treatment of symptomatic orthostatic hypotension is based primarily on a change in a surrogate marker of effectiveness, an increase in systolic blood pressure measured one minute after standing, a surrogate marker considered likely to correspond to a clinical benefit.
Contraindications
- CONTRAINDICATIONS Midodrine hydrochloride tablets are contraindicated in patients with severe organic heart disease, acute renal disease, urinary retention, pheochromocytoma or thyrotoxicosis. Midodrine should not be used in patients with persistent and excessive supine hypertension.
Side Effects
- ADVERSE REACTIONS The most frequent adverse reactions seen in controlled trials were supine and sitting hypertension; paresthesia and pruritus, mainly of the scalp; goosebumps; chills; urinary urge; urinary retention and urinary frequency. The frequency of these events in a 3-week placebo-controlled trial is shown in the following table: Adverse Events Placebo n=88 Midodrine n=82 Event # of reports % of patients # of reports % of patients Total # of reports 22 77 Paresthesia 1 4 4.5 15 18.3 Piloerection 0 0 11 13.4 Dysuria 2 0 0 11 13.4 Pruritis 3 2 2.3 10 12.2 Supine hypertension 4 0 0 6 7.
Interactions
- Drug Interactions When administered concomitantly with midodrine, cardiac glycosides may enhance or precipitate bradycardia, A.V. block or arrhythmia. The risk of hypertension increases with concomitant administration of drugs that increase blood pressure (phenylephrine, pseudoephedrine, ephedrine, dihydroergotamine, thyroid hormones, or droxidopa). Avoid concomitant use of drugs that increase blood pressure. If concomitant use cannot be avoided, monitor blood pressure closely. Avoid use of MAO inhibitors or linezolid with midodrine.