BIORPHEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BIORPHEN (BIORPHEN).
Biorphen (phenylephrine) is a selective alpha-1 adrenergic receptor agonist causing vasoconstriction and increased blood pressure.
| 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. |
| Molecular Weight | 401.5 |
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. |
| 1st trimester | Avoid; not recommended due to potential teratogenic effects. |
| 2nd trimester | Avoid; not recommended unless benefit outweighs risk. |
| 3rd trimester | Avoid; may cause neonatal respiratory depression and withdrawal. |
Clinical note
Comprehensive clinical and safety monograph for BIORPHEN (BIORPHEN).
| Placental transfer | Crosses placenta with fetal concentrations approaching maternal levels. |
| Breastfeeding | Contraindicated due to excretion into breast milk and risk of respiratory depression and withdrawal in infants. Use alternative agents. |
| Lactation Rating | L5 - Contraindicated |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
Hypersensitivity to buprenorphine or naloxoneSevere respiratory depressionAcute or severe bronchial asthmaKnown or suspected gastrointestinal obstructionConcurrent use of MAOIs or within 14 days
| 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. |
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| 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. |
| Fetal Monitoring | Monitor maternal respiratory function, sedation level, and signs of withdrawal. Fetal monitoring includes assessment of fetal heart rate, amniotic fluid index, and fetal growth ultrasound due to risk of IUGR. In late pregnancy, monitor for neonatal respiratory depression and withdrawal after delivery. |
| Fertility Effects | BIORPHEN may impair fertility in females by disrupting menstrual cycles and ovulation. In males, it may reduce sperm count and motility. Effects are typically reversible upon discontinuation. |
| Clinical Pearls |
| BIORPHEN (bioresmethrin) is a pyrethroid insecticide used topically for pediculosis. Avoid contact with eyes and mucous membranes. Do not use on open wounds or broken skin. Reapply after 7-10 days if live lice persist. Resistance is rare but monitor efficacy. |
| Patient Advice | Apply only to dry hair and scalp, avoiding eyes. · Leave on for 10 minutes, then rinse thoroughly. · Use a fine-toothed comb to remove nits. · Do not use more than once daily or exceed recommended duration. · Wash bedding and clothing in hot water. · Inform doctor if itching or irritation persists. |