Topical Phenylephrine (AnuMed) - Uses, Dose, Warnings, MOA

Topical Phenylephrine (AnuMed) is a sympathetic alpha-adrenergic receptor agonist that can cause vasoconstriction when applied topically. It is used to treat piles.

Topical Phenylephrine Uses:

It is used as an OTC medicine for the treatment of hemorrhoids (piles).

Topical Phenylephrine (AnuMed) Dose in Adults

Topical Phenylephrine (AnuMed) Dose in the treatment of Hemorrhoids: Rectal:

Ointment:
- Apply to the clean, dry area up to four times a day
Suppository:
- Insert one suppository rectally up to four times a day

Topical Phenylephrine (AnuMed) Dose in Childrens

Topical Phenylephrine (AnuMed) Dose in the treatment of Hemorrhoids, anorectal protection:

Children ≥12 years and Adolescents:
- Ointment: Topical or rectal:
  - Apply to the rectal area or by the applicator into the rectum up to four times a day (after each bowel movements and in the morning and night)
- Suppository: Rectal:
  - Insert one suppository into the rectum up to four times a day (eg, morning, night, and after each bowel movements)

Pregnancy Risk Category: C

When administered intravenously, phenylephrine crosses over the placental boundary.
Refer to the Phenylephrine (Systemic) monograph for details.
There are limited data available on the topical application of phenylephrine to hemorhoids during pregnancy.
Patients with hypertension or diabetes should not use the topical application while pregnant.

Use of phenylephrine during breastfeeding

It is unknown if phenylephrine can be excreted into breastmilk.

Use in Renal Disease:

No dosage adjustment has been recommended by the manufactuer.

Use in Liver Diseases:

No dosage adjustments have been recommended by the manufacturer.

Side effects of Topical Phenylephrine (AnuMed):

Rare systemic effects may occur. See: Phenylephrine Injection Side effects

Contraindications to Topical Phenylephrine (AnuMed):

Hypersensitivity to phenylephrine and any component of the formulation
Hypertension;
Tachycardia ventriculare

Warnings and precautions

Cardiovascular disease, which includes ischemic heart disease.
- Be aware that the drug is not fully absorbed and can cause angina or ventricular arrhythmias.
Diabetes mellitus:
- Be careful. Some patients may experience an increase in their diabetes control.
Hyperthyroidism:
- Please exercise caution. Hyperthyroidism symptoms may get worse.

Phenylephrine (topical): Drug Interaction

Risk Factor C (Monitor therapy)
Alpha1-Blockers	May diminish the vasoconstricting effect of Alpha1-Agonists. Similarly, Alpha1Agonists may antagonize Alpha1-Blocker vasodilation.
AtoMOXetine	May enhance the hypertensive effect of Sympathomimetics. AtoMOXetine may enhance the tachycardic effect of Sympathomimetics.
Cannabinoid-Containing Products	May enhance the tachycardic effect of Sympathomimetics. Exceptions: Cannabidiol.
Doxofylline	Sympathomimetics may enhance the adverse/toxic effect of Doxofylline.
Guanethidine	May enhance the arrhythmogenic effect of Sympathomimetics. Guanethidine may enhance the hypertensive effect of Sympathomimetics.
Solriamfetol	Sympathomimetics may enhance the hypertensive effect of Solriamfetol.
Sympathomimetics	May enhance the adverse/toxic effect of other Sympathomimetics.
Tedizolid	May enhance the hypertensive effect of Sympathomimetics. Tedizolid may enhance the tachycardic effect of Sympathomimetics.
Tricyclic Antidepressants	May enhance the therapeutic effect of Alpha1-Agonists. Tricyclic Antidepressants may diminish the therapeutic effect of Alpha1-Agonists.
Risk Factor D (Consider therapy modification)
Cocaine (Topical)	May enhance the hypertensive effect of Sympathomimetics. Management: Consider alternatives to use of this combination when possible. Monitor closely for substantially increased blood pressure or heart rate and for any evidence of myocardial ischemia with concurrent use.
Linezolid	May enhance the hypertensive effect of Sympathomimetics. Management: Reduce initial doses of sympathomimetic agents, and closely monitor for enhanced pressor response, in patients receiving linezolid. Specific dose adjustment recommendations are not presently available.
Risk Factor X (Avoid combination)
Ergot Derivatives	May enhance the hypertensive effect of Alpha1-Agonists. Ergot Derivatives may enhance the vasoconstricting effect of Alpha1-Agonists. Exceptions: Ergoloid Mesylates; Nicergoline.
Iobenguane Radiopharmaceutical Products	Alpha1-Agonists may diminish the therapeutic effect of Iobenguane Radiopharmaceutical Products. Management: Discontinue all drugs that may inhibit or interfere with catecholamine transport or uptake for at least 5 biological half-lives before iobenguane administration. Do not administer these drugs until at least 7 days after each iobenguane dose.
Monoamine Oxidase Inhibitors	May enhance the hypertensive effect of Alpha1-Agonists. While linezolid is expected to interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to linezolid specific monographs for details. Exceptions: Linezolid; Tedizolid.

Monitoring Parameters:

Monitor the response to therapy.
Observe for symptoms of sympathetic overdrive such as tachycardia and hypertension.

How to administer Topical Phenylephrine (AnuMed)?

Ointment:

Clean the anorectal area with a wipe. Gently dry the area by padding. apply the ointment gently into the outer anal canal and external area.

Suppository:

Insert the suppository after each bowel movement and cleansing the area into the lower anal canal.

Mechanism of action of Topical Phenylephrine (AnuMed):

Phenylephrine, a powerful and direct-acting alpha–adrenergic stimulating drug with minimal beta-adrenergic activation, is potent.
It causes local vasoconstriction when applied topically.