Dosing & Uses
Dosage Forms & Strengths
acetaminophen/doxylamine/dextromethorphan/phenylephrine
capsule
- 325mg/6.25mg/10mg/5mg
Congestion, Rhinorrhea, Cough, Sore Throat, Headache, Fever, Minor Aches & Pains
2 caps PO q4hr PRN; not to exceed 12 caps/day
Dosage Forms & Strengths
acetaminophen/doxylamine/dextromethorphan/phenylephrine
capsule
- 325mg/6.25mg/10mg/5mg
Congestion, Rhinorrhea, Cough, Sore Throat, Headache, Fever, Minor Aches & Pains
<12 Years
- Ask a pediatrician
≥12 Years
- 2 caps PO q4hr PRN; not to exceed 12 caps/day
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Adverse Effects
Frequency Not Defined
Hypertension
Reflex tachycardia
Severe peripheral and visceral vasoconstriction
Dizziness
Drowsiness
Excitability
Headache
Restlessness
Tremor
Dermatologic rash
GI disturbances
Anemia blood dyscrasias (neutropenia, pancytopenia, leukopenia)
Bilirubin & alkaline phosphatase may increase
Dry mouth, throat, and nose
Thickening of mucus in nose or throat
Warnings
Contraindications
Hypersensitivity
Asthma
Narrow-angle glaucoma
Symptomatic prostate hypertrophy
Bladder-neck obstruction
Stenosing peptic ulcer
G-6-PD deficiency
Severe hepatic impairment
Cautions
Acetaminophen hepatotoxicity possible in chronic alcoholics following various dose levels; severe or recurrent pain or high or continued fever may indicate a serious illness
Acetaminophen contained in many OTC products & combined use with these products may result in toxicity due to cumulative doses exceeding recommended maximum dose
Do not take dextromethorphan for persistent or chronic cough associated with smoking, asthma, or emphysema, or if it is accompanied by excessive phlegm unless directed by a healthcare provider
Dextromethorphan may slow respiration rate
Doxylamine may exacerbate angle closure glaucoma, hyperthyroidism, peptic ulcer, or urinary tract obstruction; xerostomia may occur
Pregnancy & Lactation
Pregnancy category: C
Lactation: excreted in breast milk, use caution
Pregnant or breastfeeding patients should seek advice of health professional before using OTC drugs
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Acetaminophen: blocks pain impulse generation peripherally & may inhibit the generation of prostaglandin in the CNS; reduces fever by inhibiting the hypothalamic heat-regulating center
Acetaminophen: Risk for rare, but serious skin reactions that can be fatal; these reactions include Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP); symptoms may include skin redness, blisters and rash
Dextromethorphan: cough suppressant that acts centrally on the cough center in the medulla
Doxylamine competitively blocks histamine from binding to H1 receptors; significant antimuscarinic activity and penetrates CNS, which causes pronounced tendency to induce sedation
Phenylephrine is a vasoconstrictor and a decongestant that relieves symptoms resulting from irritation of upper respiratory tract tissue; shrinks swollen mucous membranes, reduces nasal congestion and tissue hyperemia
Pharmacokinetics
Acetaminophen
- Peak plasma time: 10-60 min (PO immediate release); 60-120 min (PO extended release); 6 hr (PO 500 mg tablet); 8 hr (PO 650 mg extended release tablet)
- Vd: 1 L/kg
- Protein binding: 10-25%
- Metabolism: Liver (microsomal enzyme systems); conjugation (glucuronic acid)
- Half-life: 1.25-3hr
- Excretion: Urine
Dextromethorphan
- Onset: 15-30 min
- Duration: 3-6 hr
- Metabolism: Hepatic P450 enzyme CYP2D6
- Excretion: Urine
- Half-life: 2-4 hr (extensive metabolizers); 24 hr (poor metabolizers)
- Peak plasma time: 2-3 hr
Phenylephrine
- Half-life: 2-3 hr
- Onset: 10-15 min
- Duration: 15 min
- Bioavailability: < 38%
- Excretion: Urine (80-90%)
- Peak plasma time: 0.75-2 hr
- Vd: 26-61 L
- Vdss: 340 L
Doxylamine
- Peak plasma time: 2-3 hr
- Half-life: 10-12 hr
- Excretion: Urine
- Metabolism: Liver (CYP450)