Mydcombi (phenylephrine HCl/tropicamide)

To produce mydriasis for funduscopic examination of the eye, 1 or 2 drops of a 0.5% solution of tropicamide may be instilled onto the eye(s) 15-20 minutes before examination. In patients with heavily pigmented irides, higher solution concentrations may be required. To produce cycloplegia for refraction, a 1% solution should be used; 1 or 2 drops of this solution may be instilled onto the eye(s) and repeated in 5 minutes. The examination must be performed within 30 minutes after the second instillation. If the patient is not examined within 20-30 minutes, an additional drop of the 1% solution should be instilled.

When a combination preparation containing tropicamide and hydroxyamphetamine hydrobromide is used to produce mydriasis, 1 or 2 drops of the solution may be instilled onto the eye(s). Patients with lighter irides may experience slightly greater mydriasis than patients with darker irides.

Phenylephrine hydrochloride ophthalmic solutions are applied topically to the conjunctiva or cornea. A local anesthetic other than butacaine (See Chemistry and Stability: Stability) may be instilled prior to phenylephrine to prevent stinging and lacrimation.

Tropicamide is applied topically to the eye. To avoid excessive systemic absorption, finger pressure should be applied on the lacrimal sac for 1-2 minutes following topical instillation of the solution. Care should be taken to avoid contamination of the solution container.

No dosing information is available for this tab.

No dosing information is available for this tab.

Concomitant administration of phenylephrine with cycloplegic antimuscarinic drugs such as atropine sulfate, cyclopentolate hydrochloride, homatropine hydrobromide, or scopolamine hydrobromide produces increased dilation of the pupil which is of clinical value.

Administration of a 10% solution of phenylephrine hydrochloride to patients pretreated with 2% pilocarpine hydrochloride produces mydriasis but to a lesser degree than occurs in patients who are not receiving the miotic. Pilocarpine may prevent or reduce visual disturbances and the risk of increased intraocular pressure associated with mydriasis in some patients and may be used to hasten recovery from mydriasis after ophthalmologic examination. Phenylephrine may reduce ciliary and conjunctival congestion and accommodative myopia often encountered when miotics are used alone in the treatment of glaucoma, without compromising the effectiveness of glaucoma therapy.

Phenylephrine must be administered under careful supervision and in reduced dosage if used within 21 days after the patient has received a monoamine oxidase inhibitor because potentiation of the pressor effects of phenylephrine may result. The pressor response to phenylephrine may also be potentiated if a tricyclic antidepressant is administered concomitantly.

If phenylephrine is administered to a patient undergoing chronic oral therapy with guanethidine, the pupillary response to phenylephrine is greatly increased and the pressor response may also be potentiated. Phenylephrine should be administered cautiously to patients receiving guanethidine.

The mydriatic response to phenylephrine is decreased in patients receiving levodopa.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

Moderate Interaction: Assess the risk to the patient and take action as needed.

Sympathomimetics/Rauwolfia Alkaloids

SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed.

MECHANISM OF ACTION: Reserpine depletes catecholamine stores within the peripheral vascular adrenergic nerve endings, thus indirect acting sympathomimetics are unable to trigger the release of catecholamines. The reserpine-induced catecholamine release increases sensitivity to the effects of direct acting sympathomimetics.

CLINICAL EFFECTS: Increased effects of direct acting sympathomimetics. Decreased effects of indirect acting sympathomimetics. Mixed acting sympathomimetics will show effects based on the predominance of either direct or indirect activity.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: If these agents are administered concurrently, monitor blood pressure. The dose of the sympathomimetic may need to be adjusted.

DISCUSSION: This interaction has been well documented in animal studies and human case reports have confirmed the interaction. Reserpine has been shown to decrease the response to epinephrine administered for hypotension. Reserpine has also been shown to decrease the effectiveness of ophthalmic epinephrine, a direct acting sympathomimetic. Ophthalmic phenylephrine has been shown to decrease the hypotensive effects of reserpine.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

• Angle-closure glaucoma
• Ocular hypertension

• Atherosclerotic cardiovascular disease
• Benign prostatic hyperplasia
• Cardiac arrhythmia
• Coronary artery disease
• Diabetes mellitus
• Hypertension
• Hyperthyroidism

There is no enhanced messaging for this drug.

Rare or Very Rare

• Acute cognitive impairment
• Behavioral disorders
• Cardiac arrhythmia
• Dizziness
• Drowsy
• Drug-induced psychosis
• Dyskinesia
• Fatigue
• Flushing
• Hallucinations
• Hyperhidrosis
• Hypertension
• Pallor
• Polydipsia
• Skin rash
• Slurred speech
• Tachycardia
• Tachycardia
• Tremor
• Xerostomia

More Frequent

• Eye tearing
• Headache disorder
• Ocular irritation
• Ocular pain
• Photophobia

Less Frequent

• Blurred vision
• Headache disorder
• Ocular pain
• Photophobia

No enhanced messaging available.

No enhanced messaging available.

Animal reproduction studies have not been performed with phenylephrine. It is not known whether topically applied phenylephrine can cause fetal harm when administered to pregnant women. Parenterally administered phenylephrine in late pregnancy or labor may cause fetal anoxia. (See Cautions: Pregnancy and Lactation, in Phenylephrine Hydrochloride 12:12.04.) Topically applied phenylephrine should be used during pregnancy only when clearly needed.

Animal reproduction studies have not been performed with tropicamide. It is not known whether tropicamide can cause fetal harm when administered to pregnant women. Tropicamide should be used during pregnancy only when clearly needed.

Since it is not known whether phenylephrine is distributed into milk, the drug should be used with caution in nursing women.

It is not known whether tropicamide is distributed into milk. Because many drugs are distributed into milk, tropicamide should be used with caution in nursing women.

No enhanced messaging available.