Midodrine belongs to the class of medications known as vasopressors. It is used to relieve symptoms of low blood pressure (such as dizziness, lightheadedness, and fainting) for people with Parkinson's disease, diabetes, Bradbury-Eggleston syndrome, and Shy-Drager syndrome. It works by constricting the blood vessels, causing an increase in blood pressure.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual recommended starting dose of midodrine for adults is 2.5 mg 3 times daily, taken with or without food. Midodrine may also be taken as frequently as 6 times a day, as long as the maximum daily dose of 30 mg is not exceeded. The last midodrine dose of the day should be taken at least 4 hours before bedtime. People with kidney disease may need lower doses.

Midodrine will be started under close medical supervision, usually in a hospital, clinic, or doctor's office. Both lying and sitting blood pressures should be measured every hour for 3 hours after the first and second doses of midodrine therapy and also when there is an increase in dose. Thereafter, blood pressures should be measured daily for the first month, and then twice weekly while on therapy. Midodrine should only be continued if the person appears to have improvement in their symptoms during the initial treatment.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue on with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light, and keep it away from heat and out of the reach of children.

2.5 mg
Each white-to-off-white, round, scored tablet debossed with "H" above the score line and "P" below the score on one side and "504" on the other side, contains 2.5 mg of midodrine. Nonmedicinal ingredients: colloidal silicon dioxide, magnesium stearate, microcrystalline cellulose, and pregelatinized starch.

5 mg
Each light-orange-coloured, round, scored tablet debossed with "H" above the score and "P" below the score on one side and "505" on the other side, contains 5 mg of midodrine. Nonmedicinal ingredients: colloidal silicon dioxide, magnesium stearate, microcrystalline cellulose, pregelatinized starch, and the colourant FD&C Yellow No. 6/Sunset Yellow FCF Aluminum Lake.

Do not use this medication if you:

• are allergic to midodrine or to any of the ingredients of the medication
• have a condition known as pheochromocytoma (a tumour of the adrenal gland)
• have acute kidney disease
• have high blood pressure
• have blood vessel disease that causes narrowing of blockage of blood vessels
• have narrow angle glaucoma
• have an enlarged prostate
• have an overactive thyroid
• have difficulty passing urine
• have persistent and excessive supine hypertension (high blood pressure when lying down)
• have severe heart disease

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• burning, tingling, or prickling of the scalp or skin
• chills
• dizziness
• erection of body hair
• goose bumps
• heartburn
• increased or altered sensitivity to touch
• irritability
• itchy skin or scalp
• nausea
• stomach pain
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• abnormal heartbeat
• abnormal loss of strength
• headache
• nervousness
• pounding in the ears
• skin rash
• slow heartbeat
• urinary problems (e.g., urinary frequency (urinating more often than usual), retention (difficulty passing urine), pain, or urgency (urgent need to urinate)
• vision problems (e.g., blurred vision, wavy vision, dark spots, sudden loss of vision)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• increased dizziness or faintness
• loss of vision
• persistently elevated supine (lying) blood pressure
• shortness of breath
• signs of an allergic reaction (shortness of breath or difficulty breathing; hives; swelling of the eyes, mouth, lips, or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Abnormal heart rhythms: If you have abnormal heart rhythms, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Bladder problems: Midodrine can cause urinary retention or worsen existing urinary retention. If you have bladder problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Diabetes: If you have diabetes and have experienced low blood pressure when rising from a sitting or lying position to a standing position, your doctor should closely monitor your condition while you are taking this medication.

Heart problems: Midodrine can cause slowing of your heartbeat. Report any slow heartbeat, increased dizziness, or fainting spells to your doctor immediately.

Kidney function: People with reduced kidney function do not clear midodrine from their bodies as quickly as people with regular kidney function. Lower doses of this medication and close monitoring by your doctor may be needed.

Liver function: If you have reduced liver function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Supine hypertension: Midodrine can cause supine hypertension (high blood pressure when lying down), and persistently high supine blood pressure can lead to strokes, heart attacks, heart failure, and kidney problems. People on midodrine should have their supine (lying on the back) and sitting blood pressures monitored regularly. If you have symptoms of supine hypertension (such as pounding in the ears, headache, heartbeat awareness, or blurred vision), stop using midodrine and contact your doctor immediately.

Visual problems: If you have visual problems (e.g., glaucoma), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if midodrine passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children 12 years of age and younger.

There may be an interaction between midodrine and any of the following:

• alpha-agonists (e.g., clonidine, guanfacine)
• alpha-blockers (e.g., alfuzosin, doxazosin, silodosin, tamsulosin)
• amiodarone
• amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
• atomoxetine
• atropine
• beta-blockers (e.g., atenolol, metoprolol, nadolol, propranolol)
• bromocriptine
• bronchodilators (e.g., formoterol, salbutamol, salmeterol, terbutaline)
• caffeine
• decongestant cold medications (e.g., phenylephrine, pseudoephedrine)
• decongestant eye drops and nose sprays (e.g., naphazoline, oxymetazoline, xylometazoline)
• digoxin
• diltiazem
• donepezil
• dopamine
• dronedarone
• epinephrine
• ergot alkaloids (e.g., ergotamine, dihydroergotamine)
• fentanyl
• flecainide
• galantamine
• iodinated contrast agents
• isoproterenol
• ivabradine
• levothyroxine
• linezolid
• methylphenidate
• modafinil
• monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, rasagiline, selegiline, tranylcypromine)
• nabilone
• neostigmine
• norepinephrine
• octreotide
• procainamide
• propafenone
• protein kinase inhibitors (e.g., brigatinib, ceritinib)
• pyridostigmine
• rivastigmine
• somatostatin analogues (e.g., lanreotide, octreotide, pasireotide)
• sphingosine 1-phosphate (S1P) receptor inhibitors (e.g., fingolimod, ozanimod, ponesimod, siponimod)
• theophyllines (e.g., aminophylline, theophylline)
• tizanidine
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• verapamil

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than the ones listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.