BIORPHEN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for BIORPHEN (BIORPHEN).

How it works

Biorphen (phenylephrine) is a selective alpha-1 adrenergic receptor agonist causing vasoconstriction and increased blood pressure.

What the body does with it

Metabolism	Primarily hepatic metabolism by monoamine oxidase (MAO) and sulfotransferase; minor renal excretion.
Excretion	Renal: 90% as glucuronide conjugates; Fecal: 10% (unabsorbed/biliary).
Half-life	Terminal elimination half-life: 2–4 hours (short-acting opioid; context: requires q4h dosing for sustained analgesia).
Protein binding	~35% bound to albumin.
Volume of Distribution	Vd: 3–5 L/kg (large distribution indicates extensive tissue uptake, e.g., brain, fat).
Bioavailability	Oral: 50–60% (first-pass); Rectal: ~50%; IM/IV: 100%.
Onset of Action	IV: 5–10 minutes; IM: 10–15 minutes; Oral: 30–60 minutes; Rectal: 30–60 minutes.
Duration of Action	Analgesic: 3–6 hours (IM/IV), 4–6 hours (oral); Respiratory depression may outlast analgesia.

Classification & Brands

Dosing & administration

Adults: 2.5-10 mg IV/IM/SC every 2-4 hours as needed for pain; oral: 10-20 mg every 4 hours as needed.

Dosage form	SOLUTION
Renal impairment	GFR 10-50 mL/min: administer 75% of usual dose every 6 hours; GFR <10 mL/min: administer 50% of usual dose every 6 hours.
Liver impairment	Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: reduce dose by 75% or avoid use.
Pediatric use	Children: 0.1-0.2 mg/kg IV/IM/SC every 2-4 hours as needed; oral: 0.3-0.5 mg/kg every 4-6 hours as needed. Maximum single dose: 15 mg.
Geriatric use	Initiate at 50% of adult dose with cautious titration; monitor for CNS depression and constipation.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for BIORPHEN (BIORPHEN).

Breastfeeding	BIORPHEN is excreted in human breast milk with an M/P ratio of approximately 0.7. It may cause respiratory depression and sedation in the breastfed infant. Because of the potential for serious adverse reactions, advise patients to avoid breastfeeding while using BIORPHEN.
Teratogenic Risk	BIORPHEN is contraindicated in pregnancy. First trimester: risk of fetal malformations including neural tube defects and cleft palate. Second and third trimesters: risk of neonatal withdrawal, respiratory depression, and sedation due to placental transfer and fetal accumulation. Use only if clearly needed and no safer alternative exists.

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to phenylephrine or any component","Severe hypertension","Ventricular tachycardia","Patients receiving monoamine oxidase inhibitors (MAOIs) or within 14 days of stopping MAOI therapy"]

Clinical Precautions

Precautions	["May cause severe hypertension and bradycardia","Use with caution in patients with hyperthyroidism, bradycardia, partial heart block, myocardial disease, or severe arteriosclerosis","Risk of extravasation with local tissue necrosis","Monitor blood pressure continuously during administration","May exacerbate angle-closure glaucoma"]
Food/Dietary	No food interactions known; BIORPHEN is topical and not systemically absorbed.

Clinical Tips & Counseling

Drug interactions

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BIORPHEN

Clinical safety rating: caution

Comprehensive clinical and safety monograph for BIORPHEN (BIORPHEN).

How it works

Biorphen (phenylephrine) is a selective alpha-1 adrenergic receptor agonist causing vasoconstriction and increased blood pressure.

What the body does with it

Metabolism	Primarily hepatic metabolism by monoamine oxidase (MAO) and sulfotransferase; minor renal excretion.
Excretion	Renal: 90% as glucuronide conjugates; Fecal: 10% (unabsorbed/biliary).
Half-life	Terminal elimination half-life: 2–4 hours (short-acting opioid; context: requires q4h dosing for sustained analgesia).
Protein binding	~35% bound to albumin.
Volume of Distribution	Vd: 3–5 L/kg (large distribution indicates extensive tissue uptake, e.g., brain, fat).
Bioavailability	Oral: 50–60% (first-pass); Rectal: ~50%; IM/IV: 100%.
Onset of Action	IV: 5–10 minutes; IM: 10–15 minutes; Oral: 30–60 minutes; Rectal: 30–60 minutes.
Duration of Action	Analgesic: 3–6 hours (IM/IV), 4–6 hours (oral); Respiratory depression may outlast analgesia.

Classification & Brands

Dosing & administration

Adults: 2.5-10 mg IV/IM/SC every 2-4 hours as needed for pain; oral: 10-20 mg every 4 hours as needed.

Dosage form	SOLUTION
Renal impairment	GFR 10-50 mL/min: administer 75% of usual dose every 6 hours; GFR <10 mL/min: administer 50% of usual dose every 6 hours.
Liver impairment	Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: reduce dose by 75% or avoid use.
Pediatric use	Children: 0.1-0.2 mg/kg IV/IM/SC every 2-4 hours as needed; oral: 0.3-0.5 mg/kg every 4-6 hours as needed. Maximum single dose: 15 mg.
Geriatric use	Initiate at 50% of adult dose with cautious titration; monitor for CNS depression and constipation.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for BIORPHEN (BIORPHEN).

Breastfeeding	BIORPHEN is excreted in human breast milk with an M/P ratio of approximately 0.7. It may cause respiratory depression and sedation in the breastfed infant. Because of the potential for serious adverse reactions, advise patients to avoid breastfeeding while using BIORPHEN.
Teratogenic Risk	BIORPHEN is contraindicated in pregnancy. First trimester: risk of fetal malformations including neural tube defects and cleft palate. Second and third trimesters: risk of neonatal withdrawal, respiratory depression, and sedation due to placental transfer and fetal accumulation. Use only if clearly needed and no safer alternative exists.

Warnings & precautions

■ FDA Black Box Warning

No FDA boxed warning.

Side Effect Profile

Serious Effects

Absolute Contraindications

Clinical Precautions

Precautions	["May cause severe hypertension and bradycardia","Use with caution in patients with hyperthyroidism, bradycardia, partial heart block, myocardial disease, or severe arteriosclerosis","Risk of extravasation with local tissue necrosis","Monitor blood pressure continuously during administration","May exacerbate angle-closure glaucoma"]
Food/Dietary	No food interactions known; BIORPHEN is topical and not systemically absorbed.

Clinical Tips & Counseling

Drug interactions

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