doxylamine/dextromethorphan (Vicks NyQuil Cough, Safetussin PM)
Classes: Antitussives, Non-narcotic Combos
Dosing and uses of Vicks NyQuil Cough, Safetussin PM (doxylamine/dextromethorphan)
Adult dosage forms and strengths
doxylamine/dextromethorphan
oral liquid
- (3.125mg/7.5mg)/5mL
- (6.25mg/15mg)/15mL
Cough, Rhinorrhea & Sneezing
Vicks NyQuil Cough: 30 mL PO q6hr; not to exceed 4 doses/day
Safetussin PM: 20 mL PO q6hr (3.125 mg/7.5 mg per 5 mL)
Pediatric dosage forms and strengths
doxylamine/dextromethorphan
oral liquid
- (3.125mg/7.5mg)/5mL
- (6.25mg/15mg)/15mL
Cough, Rhinorrhea & Sneezing
Vicks NyQuil Cough
- <4 years old: Do not use
- 4-12 years old: Ask a pediatrician
- >12 years old: 30 mL PO q6hr; not to exceed 4 doses/day
Safetussin Pm
- <4 years old: Do not use
- 4-12 years old: Ask a pediatrician
- 12 years or older: 20 mL PO q6hr (3.125 mg/7.5 mg per 5 mL)
Vicks NyQuil Cough, Safetussin PM (doxylamine/dextromethorphan) adverse (side) effects
Common Adverse effects
Dizziness
Drowsiness
GI disturbances
Dry mouth, throat, and nose
Thickening of mucus in nose or throat
Warnings
Contraindications
Hypersensitivity
Asthma attacks
Narrow-angle glaucoma
Symptomatic prostate hypertrophy
Bladder-neck obstruction
Stenosing peptic ulcer
Cautions
Doxylamine: May exacerbate angle closure glaucoma, hyperthyroidism, peptic ulcer, or urinary tract obstruction; xerostomia may occur
Dextromethorphan: Do not take 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; may decrease respiration rate
Pregnancy and 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 of Vicks NyQuil Cough, Safetussin PM (doxylamine/dextromethorphan)
Mechanism of action
Doxylamine: competitively blocks histamine from binding to H1 receptors; significant antimuscarinic activity & penetrates CNS, which causes pronounced themdency to induce sedation
Dextromethorphan: cough suppressant that acts centrally on the cough center in medulla
