What is Mydfrin (Phenylephrine Ophthalmic)?

Phenylephrine ophthalmic causes constriction of blood vessels in the eyes. It also enlarges the pupils, reduces the production of fluid in the eyes, and increases the amount of fluid that drains from the eyes.
Phenylephrine ophthalmic available over-the-counter is used to relieve redness, burning, irritation, and dryness of the eye caused by wind, sun, and other minor irritants. Prescription-strength phenylephrine ophthalmic 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.
Phenylephrine ophthalmic may also be used for purposes other than those listed in this medication guide.

What is the most important information I should know about Mydfrin (Phenylephrine Ophthalmic)?

Do not touch the dropper to any surface, including the eyes or hands. The dropper is sterile. If it becomes contaminated, it could cause an infection in the eye.
If you wear contact lenses, remove them before applying phenylephrine ophthalmic. Ask your doctor if contact lenses can be reinserted after application of the medication. Phenylephrine ophthalmic may contains preservative (benzalkonium chloride), which may cause discoloration of contact lenses.
Do not use phenylephrine ophthalmic more often or continuously for longer than 48 to 72 hours without consulting a doctor. Chronic use of this medication may damage the blood vessels (veins and arteries) in the eyes. Consult a doctor if your symptoms do not improve or appear to worsen.
Use caution when driving, operating machinery, or performing other hazardous activities. Phenylephrine ophthalmic may cause blurred vision. If you experience blurred vision, avoid these activities.

What should I discuss with my healthcare provider before taking Mydfrin (Phenylephrine Ophthalmic)?

Do not use phenylephrine ophthalmic if you have glaucoma, except under the supervision of your doctor.
Do not use phenylephrine ophthalmic after eye surgery, if you have an eye infection, if you have an eye injury, or if you have a problem with the normal tearing of your eyes without the approval and direction of your doctor. Using phenylephrine ophthalmic under these circumstances could lead to absorption of the drug by the body, and side effects could affect the heart.
Before using this medication, tell your doctor if you

• have any type of heart condition, including high blood pressure
• take any medicines to treat a heart condition
• have asthma
• have diabetes; or
• have thyroid problems

You may not be able to use phenylephrine ophthalmic, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.
Phenylephrine ophthalmic is in the FDA pregnancy category C. This means that it is not known whether phenylephrine ophthalmic will be harmful to an unborn baby. Do not use this medication without first talking to your doctor if you are pregnant or could become pregnant during treatment.
It is not known whether phenylephrine ophthalmic passes into breast milk. Do not use phenylephrine ophthalmic without first talking to your doctor if you are breast-feeding a baby.

Mydfrin Side Effects

What are the possible side effects of Mydfrin (Phenylephrine Ophthalmic)?

If you experience any of the following serious side effects, stop using phenylephrine ophthalmic and seek emergency medical attention or contact your doctor immediately:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, face, or tongue; or hives)
• an irregular or fast heart rate; or
• high blood pressure (severe headache, blurred vision, or flushed skin)

Other, less serious side effects may be more likely to occur. Continue to use phenylephrine ophthalmic and talk to your doctor if you experience

• burning, stinging, pain, or increased redness of the eye
• tearing or blurred vision
• headache
• tremor
• nausea
• sweating
• nervousness
• dizziness; or
• drowsiness

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.

Mydfrin Interactions

What other drugs affect Mydfrin (Phenylephrine Ophthalmic)?

Do not use other eye medications during treatment with phenylephrine ophthalmic except under the direction of your doctor.
Although drug interactions between phenylephrine ophthalmic and drugs taken by mouth are not expected, they can occur. Before using this medication, tell your doctor if you are taking any of the following medicines:

• a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), tranylcypromine (Parnate), or phenelzine (Nardil); or
• a beta-blocker such as propranolol (Inderal), metoprolol (Lopressor, Toprol XL), or labetalol (Normodyne, Trandate)

You may not be able to use phenylephrine ophthalmic, or you may require a dosage adjustment or special monitoring during treatment if you are taking any of the medicines listed above.
Drugs other than those listed here may also interact with phenylephrine ophthalmic. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines, including vitamins, minerals, and herbal products.

What should I avoid while taking Mydfrin (Phenylephrine Ophthalmic)?

Use caution when driving, operating machinery, or performing other hazardous activities. Phenylephrine ophthalmic may cause blurred vision. If you experience blurred vision, avoid these activities.
Do not touch the dropper to any surface, including the eyes or hands. The dropper is sterile. If it becomes contaminated, it could cause an infection in the eye.
If you wear contact lenses, remove them before applying phenylephrine ophthalmic. Ask your doctor if contact lenses can be reinserted after application of the medication. Phenylephrine ophthalmic may contain a preservative (benzalkonium chloride), which may cause discoloration of contact lenses.
Do not use phenylephrine ophthalmic more often or continuously for longer than 48 to 72 hours without consulting a doctor. Chronic use of this medication may damage the blood vessels (veins and arteries) in the eyes. Consult a doctor if your symptoms do not improve or appear to worsen.

Mydfrin Dosage

How should I take Mydfrin (Phenylephrine Ophthalmic)?

Use phenylephrine eyedrops exactly as directed by your doctor, or follow the directions that accompany the package. If you do not understand these instructions, ask your doctor, pharmacist, or nurse to explain them to you.
Wash your hands before and after using the eyedrops.
If you wear contact lenses, remove them before applying phenylephrine ophthalmic. Ask your doctor if contact lenses can be reinserted after application of the medication. Phenylephrine ophthalmic may contain a preservative (benzalkonium chloride), which may cause discoloration of contact lenses.
To apply the eyedrops:

• Tilt the head back slightly and pull down on the lower eyelid. Position the dropper above the eye. Look up and away from the dropper. Squeeze out a drop and close the eye. Apply gentle pressure to the inside corner of the eye (near the nose) for about 1 minute to prevent the liquid from draining down the tear duct. Repeat the process in the other eye if needed

Do not use phenylephrine ophthalmic more often or continuously for longer than 48 to 72 hours without consulting a doctor. Chronic use of this medication may damage the blood vessels (veins and arteries) in the eyes. Consult a doctor if your symptoms do not improve or appear to worsen.
Do not touch the dropper to any surface, including the eyes or hands. The dropper is sterile. If it becomes contaminated, it could cause an infection in the eye.
Do not use any eyedrop that is discolored or has particles in it.
Store phenylephrine ophthalmic at room temperature away from moisture and heat. Keep the bottle properly capped.

What happens if I overdose on Mydfrin (Phenylephrine Ophthalmic)?

An overdose of this medication is unlikely to be harmful. If you do suspect an overdose, or if the drops have been ingested (taken by mouth), contact an emergency room or poison control center for advice.

What happens if I miss a dose of Mydfrin (Phenylephrine Ophthalmic)?

Apply the missed dose as soon as you remember. However, if it is almost time for the next regularly scheduled dose, skip the missed dose and apply the next one as directed. Do not use a double dose of this medication.
Edited from everydayhealth.com