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Mydfrin (Phenylephrine hydrochloride) Information

Mydfrin, which contains the active ingredient phenylephrine hydrochloride, is a prescription ophthalmic solution in the alpha-adrenergic agonist drug class. It is primarily used as a sympathomimetic agent to dilate the pupils. Doctors commonly use it before eye examinations, during diagnostic procedures, or before eye surgery to provide a clearer view of the inside of the eye. It is important to note that the brand name Mydfrin has been discontinued in the United States. However, generic equivalents and other brand names (like Altafrin or Neofrin) remain available.

The mechanism of action involves stimulating specific receptors in the eye muscles, causing the iris dilator muscle to contract. This results in a widened pupil and temporarily constricted blood vessels on the surface of the eye, which can also reduce redness caused by irritation from wind or sun.

Mydfrin Side Effects

Mydfrin is generally well-tolerated, but most people experience temporary local reactions as the medication takes effect. Commonly reported effects include temporary stinging or burning upon instillation, blurred vision, sensitivity to light (photophobia), and increased watering of the eyes. You may also notice a browache or headache as the eye muscles adjust.

More serious side effects can occur and require immediate medical attention. Stop taking the medication and seek help if you experience:
• Cardiovascular Issues: Pounding or irregular heartbeat, chest pain, or a sudden, significant increase in blood pressure.
• Nervous System Effects: Tremors, extreme sweating, severe dizziness, or intense anxiety.
• Severe Allergic Reactions: Hives, swelling of the face, tongue, or throat, or difficulty breathing.
• Vision Emergencies: Sudden eye pain or seeing "halos" (bright circles) around lights, which could indicate a sudden rise in eye pressure (glaucoma attack).

Mydfrin Precautions

Do not use Mydfrin if you have a known allergy to phenylephrine hydrochloride or any of the inactive ingredients in the medication. Avoid use if you have narrow-angle glaucoma, as the medication can dangerously increase intraocular pressure. Before starting treatment, inform your doctor of your complete medical history, especially if you have hypertension, heart disease, hyperthyroidism, liver disease, kidney disease, or consume large amounts of alcohol.

Tell your doctor about all medications you are taking, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements. It is critical to disclose if you have used an MAO inhibitor (a type of antidepressant) in the past 21 days, as this combination can cause a dangerous spike in blood pressure. Mydfrin may interact with tricyclic antidepressants (TCAs) and beta blockers.

Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. It is unknown if phenylephrine harms an unborn baby or passes into breast milk. It should only be used during pregnancy or while breastfeeding if clearly needed and discussed with a physician.

Use Mydfrin exactly as your doctor tells you. To apply, wash your hands and tilt your head back. Pull down the lower lid and place one drop in the pocket. To prevent the drug from entering your bloodstream, apply gentle pressure to the inner corner of the eye (near the nose) for 2 to 3 minutes after instillation. Because your pupils will be sensitive to light, wear sunglasses and avoid driving until your vision returns to normal. Do not use these drops while wearing soft contact lenses, as the preservative (benzalkonium chloride) can discolor them. Wait at least 15 minutes after application before reinserting your lenses. Store at room temperature away from light; if the solution turns dark or cloudy, discard it.

Do I need a prescription to order Mydfrin?

No, a prescription is not required from your physician to order Mydfrin.