Nyquil Liquicap Ingredients

NyQuil Sinus LiquiCaps are an over-the-counter medication indicated to alleviate symptoms associated with nasal inflammation, the common cold or flu, such as nasal congestion or sinus pressure. Patients over the age of 12 can take two NyQuil Sinus LiquiCaps every four hours and should not take more than eight liquicaps per day. This medication contains three active ingredients, which may lead to minor side effects in certain patients.

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If you are experiencing serious medical symptoms, seek emergency treatment immediately.


Acetaminophen is an analgesic medication used to alleviate sensations of headache or sinus pain in patients taking NyQuil Sinus LiquiCaps 1. Prolonged or excessive use of acetaminophen can lead to severe liver damage in certain patients 1. Side effects associated with acetaminophen are rare, though certain patients may experience an allergic reaction, warns Medline Plus, a medical information website supported by the National Institutes of Health and the U.S. National Library of Medicine 12.

Doxylamine Succinate

Ambroxol Hydrochloride Side Effects

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Doxylamine succinate is a type of medication that helps relieve allergic symptoms, such as sneezing, in treated patients. This drug is part of a class of medications called antihistamines, which block the action of histamine--an allergy-inducing substance within the human body. Side effects associated with doxylamine succinate can include dizziness and drowsiness, which may negatively affect a patient's ability to remain focused and alert during usual daily activities.

Phenylephrine HCl

Phenylephrine HCl is a nasal decongestant that helps decrease nasal pressure and congestion in patients taking NyQuil Sinus LiquiCaps 2. This medication works by decreasing inflammation within the vessels that supply blood to the nasal passageways. Side effects associated with phenylephrine HCl include sleeplessness, nervousness and dizziness, which should be discussed with a doctor if they occur, explains Medline Plus 12.

Inactive Ingredients

Active Ingredients in Sinutab

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The inactive ingredients in NyQuil Sinus LiquiCaps include coloring (FD&C Blue No. 1), glycerin, gelatin, polyethylene glycol, propylene glycol, povidone, purified water, titanium dioxide and sorbitol special. These inactive ingredients contribute to the color, shape and consistency of the liquicaps and typically are not associated with any type of side effects in treated patients.