ALLERFED

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ALLERFED (ALLERFED).

How it works

ALLERFED is a combination of an antihistamine (fexofenadine) and a decongestant (pseudoephedrine). Fexofenadine is a selective peripheral H1-receptor antagonist that blocks histamine effects, reducing allergy symptoms. Pseudoephedrine is a sympathomimetic amine that acts as a decongestant via alpha-adrenergic receptor activation, causing vasoconstriction of nasal mucosa.

What the body does with it

Metabolism	Fexofenadine is minimally metabolized (<5%) in the liver; primarily excreted unchanged in feces (80%) and urine (11%). Pseudoephedrine is partially metabolized in the liver by N-demethylation and excreted mostly unchanged in urine.
Excretion	Primarily renal (approximately 60-70% as unchanged drug and metabolites); minor biliary (10-15%); fecal (5-10%).
Half-life	Terminal elimination half-life 20-24 hours; clinically significant for once-daily dosing in seasonal allergic rhinitis.
Protein binding	80-85% bound to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Vd 5-7 L/kg, indicating extensive tissue distribution beyond plasma volume.
Bioavailability	Oral: 40-50% due to first-pass metabolism; intranasal: 70-80%.
Onset of Action	Oral: 1-2 hours; intranasal: 30 minutes.
Duration of Action	Oral: 24 hours; intranasal: 12-24 hours. Note: continuous use may require dose adjustment.

Classification & Brands

Dosing & administration

1 tablet (pseudoephedrine 60 mg / triprolidine 2.5 mg) orally every 4-6 hours; not to exceed 4 doses per 24 hours.

Dosage form	TABLET
Renal impairment	CrCl 30-50 mL/min: administer every 6-8 hours. CrCl 10-29 mL/min: administer every 8-12 hours. CrCl <10 mL/min: not recommended.
Liver impairment	Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval. Child-Pugh Class C: avoid use.
Pediatric use	Children 6-12 years: 1/2 tablet (pseudoephedrine 30 mg / triprolidine 1.25 mg) orally every 4-6 hours; max 2 doses per 24 hours. Children <6 years: not recommended.
Geriatric use	Initiate at half the adult dose; monitor for anticholinergic effects, dizziness, and hypertension; maximum 2 doses per 24 hours.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for ALLERFED (ALLERFED).

Breastfeeding	Excreted in breast milk with M/P ratio of approximately 0.5. American Academy of Pediatrics considers compatible with breastfeeding; however, use with caution due to potential for irritability and drowsiness in infant.
Teratogenic Risk	FDA Pregnancy Category C. First trimester: Limited human data; animal studies suggest possible increased risk of minor malformations. Second/third trimester: Use associated with reduced uterine blood flow and fetal tachycardia; avoid near term due to risk of prolonged QT interval in neonate.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to any component","Severe hypertension","Severe coronary artery disease","Use with or within 14 days of MAOIs","Narrow-angle glaucoma","Urinary retention","Severe renal impairment (CrCl <30 mL/min)"]

Clinical Precautions

Precautions	["Severe hypertension","Coronary artery disease","Ischemic heart disease","Increased intraocular pressure","Diabetes","Thyroid disease","Prostatic hypertrophy","Renal impairment","Use with caution in elderly","Avoid with MAOIs or within 14 days of stopping"]
Food/Dietary	Avoid high-tyramine foods (e.g., aged cheeses, cured meats, fermented foods) if taking MAOIs concurrently. Grapefruit juice may increase absorption of triprolidine. Caffeine may enhance stimulant effects of pseudoephedrine.

Clinical Tips & Counseling

Drug interactions

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ALLERFED

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ALLERFED (ALLERFED).

How it works

What the body does with it

Metabolism	Fexofenadine is minimally metabolized (<5%) in the liver; primarily excreted unchanged in feces (80%) and urine (11%). Pseudoephedrine is partially metabolized in the liver by N-demethylation and excreted mostly unchanged in urine.
Excretion	Primarily renal (approximately 60-70% as unchanged drug and metabolites); minor biliary (10-15%); fecal (5-10%).
Half-life	Terminal elimination half-life 20-24 hours; clinically significant for once-daily dosing in seasonal allergic rhinitis.
Protein binding	80-85% bound to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Vd 5-7 L/kg, indicating extensive tissue distribution beyond plasma volume.
Bioavailability	Oral: 40-50% due to first-pass metabolism; intranasal: 70-80%.
Onset of Action	Oral: 1-2 hours; intranasal: 30 minutes.
Duration of Action	Oral: 24 hours; intranasal: 12-24 hours. Note: continuous use may require dose adjustment.

Classification & Brands

Dosing & administration

1 tablet (pseudoephedrine 60 mg / triprolidine 2.5 mg) orally every 4-6 hours; not to exceed 4 doses per 24 hours.

Dosage form	TABLET
Renal impairment	CrCl 30-50 mL/min: administer every 6-8 hours. CrCl 10-29 mL/min: administer every 8-12 hours. CrCl <10 mL/min: not recommended.
Liver impairment	Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval. Child-Pugh Class C: avoid use.
Pediatric use	Children 6-12 years: 1/2 tablet (pseudoephedrine 30 mg / triprolidine 1.25 mg) orally every 4-6 hours; max 2 doses per 24 hours. Children <6 years: not recommended.
Geriatric use	Initiate at half the adult dose; monitor for anticholinergic effects, dizziness, and hypertension; maximum 2 doses per 24 hours.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for ALLERFED (ALLERFED).

Breastfeeding	Excreted in breast milk with M/P ratio of approximately 0.5. American Academy of Pediatrics considers compatible with breastfeeding; however, use with caution due to potential for irritability and drowsiness in infant.
Teratogenic Risk	FDA Pregnancy Category C. First trimester: Limited human data; animal studies suggest possible increased risk of minor malformations. Second/third trimester: Use associated with reduced uterine blood flow and fetal tachycardia; avoid near term due to risk of prolonged QT interval in neonate.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Clinical Precautions

Precautions	["Severe hypertension","Coronary artery disease","Ischemic heart disease","Increased intraocular pressure","Diabetes","Thyroid disease","Prostatic hypertrophy","Renal impairment","Use with caution in elderly","Avoid with MAOIs or within 14 days of stopping"]
Food/Dietary	Avoid high-tyramine foods (e.g., aged cheeses, cured meats, fermented foods) if taking MAOIs concurrently. Grapefruit juice may increase absorption of triprolidine. Caffeine may enhance stimulant effects of pseudoephedrine.

Clinical Tips & Counseling

Drug interactions

Loading safety data…

Clinical Pearls	Allerfed combines pseudoephedrine and triprolidine. Use with caution in hypertension, cardiovascular disease, and glaucoma. Avoid in patients with severe hypertension or coronary artery disease. Limit duration to 5-7 days to avoid rebound congestion. Anticholinergic effects may cause urinary retention in BPH.
Patient Advice	Take with food or milk to reduce stomach upset. · Do not exceed recommended dose; avoid taking more than every 4-6 hours. · Avoid alcohol while taking this medication. · If symptoms persist for more than 7 days, consult your doctor. · May cause drowsiness; avoid driving or operating heavy machinery until you know how you react.