Medically reviewed on March 14, 2018
What is Mydfrin?
Phenylephrine is a decongestant that shrinks blood vessels.
Mydfrin (for the eyes) is used to relieve eye redness, dryness, burning, and irritation caused by wind, sun, and other irritants.
Prescription-strength Mydfrin is used to constrict blood vessels in the eye and to dilate (make bigger) the pupil for conditions such as glaucoma, before surgery, and before eye examinations.
Mydfrin may also be used for purposes not listed in this medication guide.
You should not use Mydfrin if you have narrow-angle glaucoma.
Before taking this medicine
You should not use Mydfrin if you are allergic to it, or if you have narrow-angle glaucoma.
Do not use Mydfrin without a doctor's advice if you have:
an eye infection;
an eye injury; or
if you have you have recently had eye surgery.
Any of the conditions above could cause your eyes to absorb Mydfrin into your body, which could lead to dangerous effects on the heart.
Ask a doctor or pharmacist if it is safe for you to use Mydfrin if you have other medical conditions, especially:
any type of heart condition;
coronary artery disease (hardened arteries); or
asthma or sulfite allergy.
FDA pregnancy category C. It is not known whether Mydfrin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.
It is not known whether phenylephrine ophthalmic passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
Do not give this medicine to a child without medical advice.
How should I use Mydfrin?
Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.
Wash your hands before using the eye drops.
To apply the eye drops:
Tilt your head back slightly and pull down your lower eyelid to create a small pocket. Hold the dropper above the eye with the tip down. Look up and away from the dropper and squeeze out a drop.
Close your eyes for 2 or 3 minutes with your head tipped down, without blinking or squinting. Gently press your finger to the inside corner of the eye for 2 to 3 minutes, to keep the liquid from draining into your tear duct.
Use only the number of drops your doctor has prescribed, or as recommended on the medicine label. If you use more than one drop, wait about 5 minutes between drops.
Wait at least 10 minutes before using any other eye drops your doctor has prescribed.
Do not touch the tip of the eye dropper or place it directly on your eye. A contaminated dropper can infect your eye, which could lead to serious vision problems.
Do not use the eye drops if the liquid has changed colors or has particles in it. Call your pharmacist for new medicine.
Your blood pressure may need to be checked while you are using Mydfrin.
Do not use this medicine for longer than 3 days. Call your doctor if your symptoms do not improve, or if they get worse while using Mydfrin.
Long-term use of phenylephrine ophthalmic may damage the blood vessels (veins and arteries) in the eyes.
Store at room temperature away from moisture, heat, and light. Keep the bottle tightly closed when not in use.
What happens if I miss a dose?
Apply the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next dose. Do not use extra medicine to make up the missed dose.
What happens if I overdose?
An overdose of Mydfrin is not expected to be dangerous. Seek emergency medical attention or call the Poison Help line at 1-800-222-1222 if anyone has accidentally swallowed the medication.
What should I avoid while using phenylephrine ophthalmic?
Do not use Mydfrin while wearing contact lenses. Mydfrin may contain a preservative that can discolor soft contact lenses. Wait at least 15 minutes after using this medicine before putting in your contact lenses.
This medicine may cause blurred vision and may impair your reactions. Be careful if you drive or do anything that requires you to be able to see clearly.
Mydfrin side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Although the risk of serious side effects is low when Mydfrin is used in the eyes, side effects can occur if the medicine is absorbed into your bloodstream. Stop using this medicine and call your doctor at once if you have:
fast or irregular heart rate;
pale skin, light-headed feeling;
chest pain or pressure, pain spreading to your jaw or shoulder.
Less serious side effects may be more likely, and you may have none at all.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect Mydfrin?
Tell your doctor if you have used an MAO inhibitor in the past 21 days. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.
Other drugs may interact with phenylephrine ophthalmic, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 7.01.
More about Mydfrin (phenylephrine ophthalmic)
- Mydfrin Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- En Español
- 0 Reviews
- Drug class: mydriatics