Monday, May 17, 2010

Acetaminophen and phenylephrine

MEDICATION SAFETY ISSUES
Duplicate therapy issues: This product contains acetaminophen, which may be a component of combination products. Do not exceed the maximum recommended daily dose of acetaminophen.

U.S. BRAND NAMES — Alka-Seltzer Plus® Sinus Formula [OTC]; Cetafen Cold® [OTC]; Contac® Cold + Flu Maximum Strength Non-Drowsy [OTC]; Excedrin® Sinus Headache [OTC]; Mapap® Sinus Congestion and Pain Daytime [OTC]; Sinus Pain & Pressure [OTC]; Sinutab® Sinus [OTC]; Sudafed PE® Sinus Headache [OTC]; Tylenol® Sinus Congestion & Pain Daytime [OTC]; Vicks® DayQuil® Sinus [OTC]

PHARMACOLOGIC CATEGORY
Analgesic, Miscellaneous
Decongestant

DOSING: ADULTS — Sinus pain/pressure: Oral: General dosing guidelines, refer to specific product labeling: Acetaminophen 325 mg and phenylephrine 5 mg/caplet: Take 2 caplets every 4 hours as needed; maximum: 12 caplets/24 hours

DOSING: PEDIATRIC — Children ≥ 12 years: Refer to adult dosing.

DOSING: ELDERLY — Refer to adult dosing.

DOSAGE FORMS — Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Caplet, oral:
Contac® Cold + Flu Maximum Strength Non Drowsy: Acetaminophen 500 mg and phenylephrine hydrochloride 5 mg
Excedrin® Sinus Headache: Acetaminophen 325 mg and phenylephrine hydrochloride 5 mg
Mapap® Sinus Congestion and Pain Daytime, Sinutab® Sinus, Sudafed PE® Sinus Headache: Acetaminophen 325 mg and phenylephrine hydrochloride 5 mg
Tylenol® Sinus Congestion & Pain Daytime: Acetaminophen 325 mg and phenylephrine hydrochloride 5 mg [Cool Burst™ flavor]

Capsule, liquicap, oral:
Vicks® DayQuil® Sinus: Acetaminophen 325 mg and phenylephrine hydrochloride 5 mg [ethanol free]

Gelcap, oral:
Tylenol® Sinus Congestion & Pain Daytime: Acetaminophen 325 mg and phenylephrine hydrochloride 5 mg

Gelcap, rapid release, oral:
Tylenol® Sinus Congestion & Pain Datyime: Acetaminophen 325 mg and phenylephrine hydrochloride 5 mg

Tablet for solution, oral [effervescent]:
Alka-Seltzer Plus® Sinus Formula: Acetaminophen 250 mg and phenylephrine hydrochloride 5 mg [contains sodium 477 mg/tablet and phenylalanine 4.2 mg/tablet; lemon zest flavor]

Tablet, oral:
Cetafen Cold®: Acetaminophen 500 mg and phenylephrine hydrochloride 5 mg
Sinus Pain & Pressure: Acetaminophen 500 mg and phenylephrine hydrochloride 5 mg

DOSAGE FORMS: CONCISE
Caplet, oral:
Contac® Cold + Flu Maximum Strength Non Drowsy [OTC]: Acetaminophen 500 mg and phenylephrine 5 mg
Excedrin® Sinus Headache [OTC], Mapap® Sinus Congestion and Pain Daytime [OTC], Sinutab® Sinus [OTC], Sudafed PE® Sinus Headache [OTC]: Acetaminophen 325 mg and phenylephrine 5 mg
Tylenol® Sinus Congestion & Pain Daytime [OTC]: Acetaminophen 325 mg and phenylephrine 5 mg [Cool Burst™ flavor]

Capsule, liquicap, oral:
Vicks® DayQuil® Sinus [OTC]: Acetaminophen 325 mg and phenylephrine 5 mg

Gelcap, oral:
Tylenol® Sinus Congestion & Pain Daytime [OTC]: Acetaminophen 325 mg and phenylephrine 5 mg

Gelcap, rapid release, oral:
Tylenol® Sinus Congestion & Pain Daytime [OTC]: Acetaminophen 325 mg and phenylephrine 5 mg

Tablet for solution, oral [effervescent]:
Alka-Seltzer Plus® Sinus Formula [OTC]: Acetaminophen 250 mg and phenylephrine 5 mg

Tablet, oral:
Cetafen Cold® [OTC], Sinus Pain & Pressure [OTC]: Acetaminophen 500 mg and phenylephrine 5 mg

GENERIC EQUIVALENT AVAILABLE — Yes: Caplet

ADMINISTRATION — Caplets and gelcaps should be swallowed whole; do not crush, chew, or dissolve. Effervescent tablets should be dissolved in 4 ounces of water.

USE — Temporary relief of sinus/nasal congestion and pressure, headache, and minor aches and pains

ADVERSE REACTIONS SIGNIFICANT — See individual agents.

CONTRAINDICATIONS — Hypersensitivity to acetaminophen, phenylephrine, or any component of the formulation; with or within 14 days of MAO inhibitor therapy

WARNINGS / PRECAUTIONS
Disease-related concerns: Cardiovascular disease: Use with caution in patients with cardiovascular disease (including hypertension and ischemic heart disease). Diabetes: Use with caution in patients with diabetes mellitus. Ethanol use: Use with caution in patients with alcoholic liver disease; consuming ≥ 3 alcoholic drinks/day may increase the risk of liver damage. Hepatic impairment: Use caution in patients with hepatic impairment; acetaminophen may cause severe hepatic toxicity with acute overdose. Prostatic hyperplasia/urinary obstruction: Use with caution in patients with prostatic hyperplasia and/or GU obstruction. Thyroid dysfunction: Use with caution in patients with thyroid dysfunction.

Special populations: Elderly: Use with caution in the elderly; more likely to experience adverse reactions to sympathomimetics. Pediatrics: Use with caution in children; do not exceed pediatric dosing recommendations. Not for OTC use in children <12 years of age.

Dosage form specific issues: Phenylalanine: Some products may contain phenylalanine. Sodium: Some products may contain sodium; use with caution in sodium restricted patients.

Other warnings/precautions: Dosage limit: Limit acetaminophen dose to <4>3 days. Discontinue and contact healthcare provider if nervousness, dizziness, or sleeplessness occur.

METABOLISM / TRANSPORT EFFECTS — Acetaminophen: Substrate (minor) of CYP1A2, 2A6, 2C9, 2D6, 2E1, 3A4; Inhibits CYP3A4 (weak)

DRUG INTERACTIONS
Anticonvulsants (Hydantoin): May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy

Atomoxetine: May enhance the hypertensive effect of Sympathomimetics. Atomoxetine may enhance the tachycardic effect of Sympathomimetics. Risk C: Monitor therapy

Barbiturates: May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy

Cannabinoids: May enhance the tachycardic effect of Sympathomimetics. Risk C: Monitor therapy

CarBAMazepine: May increase the metabolism of Acetaminophen. This may 1) diminish the effect of acetaminophen; and 2) increase the risk of liver damage. Risk C: Monitor therapy

Cholestyramine Resin: May decrease the absorption of Acetaminophen. Effect is minimal if cholestyramine is administered 1 hour after acetaminophen. Risk D: Consider therapy modification

Imatinib: May increase the serum concentration of Acetaminophen. Risk D: Consider therapy modification

Iobenguane I 123: Sympathomimetics may diminish the therapeutic effect of Iobenguane I 123. Risk X: Avoid combination

Isoniazid: May enhance the adverse/toxic effect of Acetaminophen. Risk C: Monitor therapy

MAO Inhibitors: May enhance the hypertensive effect of Alpha1-Agonists. Risk X: Avoid combination

Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates. Risk C: Monitor therapy

Sympathomimetics: May enhance the adverse/toxic effect of other Sympathomimetics. Risk C: Monitor therapy

Tricyclic Antidepressants: May enhance the vasopressor effect of Alpha1-Agonists. Risk D: Consider therapy modification

Vitamin K Antagonists (eg, warfarin): Acetaminophen may enhance the anticoagulant effect of Vitamin K Antagonists. Most likely with daily acetaminophen doses >1.3 g for >1 week. Risk C: Monitor therapy

ETHANOL / NUTRITION / HERB INTERACTIONS — See individual agents.

DIETARY CONSIDERATIONS — Alka-Seltzer Plus® Sinus Formula contains sodium 477 mg/tablet and phenylalanine 4.2 mg/tablet

MECHANISM OF ACTION — Acetaminophen inhibits the synthesis of prostaglandins in the central nervous system and peripherally blocks pain impulse generation. Phenylephrine causes vasoconstriction of the arterioles of the nasal mucosa.

PHARMACODYNAMICS / KINETICS — See individual agents.

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