What are the ingredients in DayQuil (acetaminophen, dextromethorphan, phenylephrine)?

Ingredients in DayQuil

DayQuil contains three primary active ingredients: acetaminophen (pain reliever/fever reducer), dextromethorphan (cough suppressant), and phenylephrine (nasal decongestant).

Active Ingredients and Their Functions

1. Acetaminophen

   • Function: Analgesic and antipyretic (pain reliever and fever reducer)
   • Mechanism: Reduces pain and fever but lacks anti-inflammatory properties 1
   • Typical amount: 325-650 mg per dose
   • Safety considerations:
     • Maximum daily limit of 3-4g to prevent liver toxicity
     • FDA recommends limiting to 325 mg per tablet/capsule in prescription products 1

2. Dextromethorphan

   • Function: Antitussive (cough suppressant)
   • Mechanism: Suppresses cough reflex by acting on the cough center in the brain 2
   • Typical amount: 10-15 mg per dose
   • Safety considerations:
     • Non-sedating at therapeutic doses
     • Potential for abuse at high doses (over 1500 mg/day) which can cause psychosis 3

3. Phenylephrine

   • Function: Nasal decongestant
   • Mechanism: Alpha-1 adrenergic receptor agonist that constricts blood vessels in nasal passages 1, 4
   • Typical amount: 10 mg per dose
   • Safety considerations:
     • Less effective than pseudoephedrine as it undergoes extensive first-pass metabolism 1
     • Should be used with caution in patients with cardiovascular disease, hypertension, hyperthyroidism, or glaucoma 1

Clinical Efficacy

DayQuil has been shown to be effective in managing common cold symptoms. In clinical studies, it demonstrated efficacy comparable to other cold medications in controlling symptoms while offering fewer adverse effects and better quality of life scores 5.

Important Precautions

• Acetaminophen safety: Monitor total daily intake, especially when using multiple products containing acetaminophen, to prevent liver damage 1
• Cardiovascular risks: Phenylephrine may affect blood pressure and should be used with caution in patients with cardiovascular conditions 1
• Drug interactions:
  • Dextromethorphan may interact with MAOIs and other serotonergic medications 2
  • Phenylephrine may interact with antihypertensives and other sympathomimetics 1

Special Populations

• Elderly patients: Start with lower doses due to increased sensitivity to side effects, especially with phenylephrine 1, 4
• Patients with liver disease: Use acetaminophen with caution or at reduced doses 1
• Patients with renal impairment: Consider lower doses of phenylephrine as increased responsiveness has been observed 4

Common Pitfalls

1. Exceeding recommended acetaminophen doses: Many OTC products contain acetaminophen, which can lead to unintentional overdose when multiple products are used 1
2. Using for extended periods: These medications are intended for short-term symptom relief only
3. Using phenylephrine in high-risk patients: Those with cardiovascular disease, hypertension, or glaucoma should exercise caution 1

DayQuil is formulated as a multi-symptom cold and flu relief medication that addresses pain, fever, cough, and congestion through its three primary active ingredients, making it suitable for daytime use as it doesn't contain sedating antihistamines found in nighttime formulations.