Midodrine (Oral)

Used to treat patients who suffer from low blood pressure (hypotension), oral Midodrine works to estimate nerve endings in the blood vessels, which increases blood pressure.

Overview

Otherwise known under the US brand names Proamatine and Orvaten, oral Midodrine is a medicine given to patients who experience low blood pressure (otherwise known as hypotension). Low blood pressure can lead to feeling dizzy and lightheaded when standing (also known as orthostatic hypotension) and could cause unconsciousness in some patients. By stimulating the nerve endings in blood vessels, it causes them to constrict (or tighten), which in turn raises the patient's blood pressure. Available only on prescription from a qualified physician, it is typically supplied in tablet form.

Midodrine is usually only prescribed when a patient's blood pressure is so low it is affecting their ability to live day to day, and other treatment options are having little or no effect (such as support stockings). It belongs to a group of medicines known as sympathomimetics (alpha receptor agonists) that work on the blood vessels to increase blood pressure.

Conditions Treated

Type Of Medicine

  • Sympathomimetic (alpha receptor agonist)

Side Effects

All medicines carry the risk of causing unwanted side effects alongside their desired functions. Not all of the following side effects may appear, but if they do, some may require medical attention.

Patients who notice any of the following side effects should check with their physician immediately:

  • Cardiac awareness

Other side effects may appear that do not typically require medical attention. These kinds of side effects may retreat during treatment as the body adjusts to the effects of Midodrine. A physician should be able to guide the patient on how to prevent or reduce these side effects. Patients who are particularly concerned about their side effects should consult their physician or pharmacist for more information.

  • Chills

Some patients may experience other side effects not listed in this guide. If a patient notices any other effects, they should check with their physician or pharmacist for more advice. New side effects can also be reported to the FDA by calling 1-800-FDA-1088.

Dosage

Midodrine should not be taken by patients if they know they will be lying down for any length of time during the day. The last dose of Midodrine should not be taken after the patient's evening meal, or under four hours before they go to bed. This is because this can cause high blood pressure when lying down (known as supine hypertension), which can lead to headaches, pounding in the ears and blurred vision while lying down after taking this medication.

Different patients will require different doses of Midodrine, depending on their medical history and the specific nature of their condition. Patients should always carefully follow the directions on the label, the instructions in the patient information leaflet, and their physician's advice. The below information contains typically dosage instructions for Midodrine. Patients who have been given other instructions should not seek to change their dosage unless otherwise approved by their physician.

The amount of Midodrine required will also depend on the specific brand and the strength of the formulation. The number of doses to be taken daily, the time allocated between doses, and the total length of treatment will also depend on the nature of the medical problem it has been prescribed to treat.

In the form of oral tablets to treat low blood pressure, a typical dose is 10mg three times per day, at roughly four-hour intervals during daylight hours. This should be shortly after getting up in the morning, at midday, and lastly in the late afternoon (and not after 6pm). A patient's physician may choose to increase the dose or frequency beyond this if required. Use in children is not recommended, and any use will be determined by a physician.

If a patient misses a dose of Midodrine, they should take it as soon as they remember. However, if it is nearly time for their next dose, they should skip the missed dose and resume their usual dosing schedule. Patients should never double dose.

Major drug interactions:

Some medicines should never be used together as the risk of creating serious interactions is high. Other medicines can be used at the same time, even if there is a risk of interaction. In that case, a physician may wish to make adjustments to the dose, frequency or timing of doses for one or more of the patient's medicines to mitigate the risks. Patients who are taking Midodrine should tell their physician about all medicines they are taking - particularly, those listed below. The following interactions have been chosen for their significance. This list should not be read as all-inclusive.

  • Dihydroergotamine

Using Midodrine with any of the following medicines is typically not recommended, but may still be prescribed in some cases. If both medicines are used, a physician may wish to alter the dose or dosage instructions of one or both of the patient's medications.

  • Pseudoephedrine

Using Midodrine with any of the following medicines may raise the risk of certain side effects, but it may still be deemed the best course of treatment for the patient. If both medications are prescribed, a physician may adjust the dose, frequency or timing of doses for one or more of the patient's medicines.

  • Promethazine

Some medicines should also not be used at or around the time of eating food, or with certain types of food, as these may cause interactions to occur. Using tobacco products and drinking alcohol may also increase the risk of interactions and side effects when used with certain medicines. Patients who are concerned about food, drink or lifestyle factors should thoroughly discuss these with their physician before accepting a prescription.

Patients who have other medical issues may also experience problems while using Midodrine. Patients who have any of the following conditions should highlight them to their physician:

  • Hypertension (high blood pressure)

Warnings

When deciding to take any medicine, the benefits of taking it should be weighed very carefully against the risks of harm. This should be a detailed discussion between the patient and their physician.

Patients should always tell their physician if they have ever had any type of allergic reaction to Midodrine, or any other medications. They should also tell their physician about other types of allergies (such as dyes, animals, food or preservative allergies). When taking over the counter medications, patients should always closely read the list of ingredients on the package.

Midodrine has been used to treat a small number of children aged between six months and 12 years. There has been no evidence to date of other side effects not found in adults when used to treat children of this age with effective doses.

Similarly, studies have been conducted into the relationship between Midodrine and use in older (geriatric) patient care. It has not been known to cause different side effects or other issues in older adults, compared to those seen in younger adults.

Oral Midodrine has received a category C for use in pregnancy. This means that either animal studies have shown an adverse effect but there have not been adequate human studies to show the risks in pregnancy, or no animal or human studies have been conducted altogether.

There are no adequate studies to show any risk to infants from Midodrine use by breastfeeding female patients. Patients who are pregnant or breastfeeding should discuss the benefits and potential risks thoroughly with their physician before accepting any prescription.

Patients should not take any other medicines unless they have been checked and approved by their physician. This includes over the counter medicines for conditions such as colds, hay fever, appetite control, asthma, coughs, or sinus problems. These kinds of nonprescription medications may raise the patient's blood pressure.

Storage

As with many medicines, Midodrine should be stored firmly closed in its original packaging. It should be kept out of direct sunlight and away from moisture and heat sources. Do not allow Midodrine to freeze.

Like all medicines, Midodrine should be safely stored out of the reach of children and vulnerable adults.

Patients should not keep old, unwanted, expired or surplus medicines. Patients who have unwanted medicines should ask their pharmacist, nurse or physician for details of local take-back programs, where medicines can be safely destroyed.

Summary

Oral Midodrine is typically prescribed for patients who are experiencing the symptoms of low blood pressure (hypotension) when standing (known as orthostatic hypotension). Midodrine is usually prescribed for patients whose daily activities are severely curtailed by their condition, and after other treatment forms have been proven ineffective for their condition (such as support stockings). It belongs to a group of medicines known as sympathomimetics (or alpha receptor agonists) that work by stimulating the nerve endings in blood vessels so they constrict, and therefore raise the patient's blood pressure.