Nyquil

may be taken at bedtime for relief of major symptoms associated with colds and influenza such as nasal congestion, sniffing, headache, minor aches and pains and coughing.

Acetaminophen (Nyquil) is a pain reliever and fever reducer.

Dextromethorphan (Nyquil) is a cough suppressant. It affects the cough reflex in the brain that triggers coughing.

Doxylamine (Nyquil) is an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.

Pseudoephedrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Acetaminophen (Nyquil), Dextromethorphan (Nyquil), Doxylamine (Nyquil), and pseudoephedrine is a combination medicine used to treat headache, fever, body aches, cough, runny nose, sneezing, itching, and watery eyes caused by allergies, the common cold, or the flu.

This medicine will not treat a cough that is caused by smoking, asthma, or emphysema.

Acetaminophen (Nyquil), Dextromethorphan (Nyquil), Doxylamine (Nyquil), and pseudoephedrine may also be used for purposes not listed in this medication guide.

Usual Adult Dose for Cold Symptoms

Acetaminophen (Nyquil)/Dextromethorphan (Nyquil)/Doxylamine (Nyquil)/PSE 325 mg-15 mg-6.25 mg-30 mg oral capsule: 1 to 2 capsules orally every 6 hours not to exceed 8 capsules daily.

Usual Pediatric Dose for Cold Symptoms

Acetaminophen (Nyquil)/Dextromethorphan (Nyquil)/Doxylamine (Nyquil)/PSE 325 mg-15 mg-6.25 mg-30 mg oral capsule:

12 yrs and older: 1 to 2 capsules orally every 6 hours not to exceed 8 capsules daily.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Precautions

The FDA has not approved use of over-the-counter cough and cold medications to children aged less than 2 years, and proper dosing for children in this age group has not been studied. Clinicians should be aware of the risk for serious illness or fatal overdose from administration of cough and cold medications to children aged less than 2 years. Clinicians should be certain that caregivers understand 1) the importance of administering cough and cold medications only as directed and 2) the risk for overdose if they administer additional medications that might contain the same ingredient.

Dialysis

Data not available

See also:
What is the most important information I should know about Nyquil?

Safety during pregnancy has not been established. Do not administer concurrently with monoamine oxidase inhibitors or in patients with known hypersensitivity to any of the active ingredients.

Use Nyquil as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Nyquil may be taken with or without food.
• Use a measuring device marked for medicine dosing. Ask your pharmacist for help if you are unsure of how to measure your dose.
• If you miss a dose of Nyquil, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Nyquil.

See also:
What other drugs will affect Nyquil?

This product should not be used with the following medications because very serious (rarely fatal) interactions may occur: MAO inhibitors (e.g., furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine), sibutramine.

If you are currently using any of these medications listed above, tell your doctor or pharmacist before starting this medication. Avoid taking MAO inhibitors within 2 weeks of starting or stopping this medication.

Before using this product, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially: antispasmodics (e.g., atropine, belladonna alkaloids), beta blockers (e.g., metoprolol, atenolol), drugs for Parkinson’s disease (e.g., anticholinergics such as benztropine, trihexyphenidyl), guanethidine, certain inhaled anesthetics (e.g., halothane), memantine, methyldopa, reserpine, scopolamine, tricyclic antidepressants (e.g., amitriptyline, desipramine).

Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-seizure drugs (e.g., carbamazepine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., chlorpromazine, risperidone, amitriptyline, trazodone).

Check the labels on all your medicines (e.g., cough-and-cold products, diet aids) because they may contain ingredients that could affect your heart rate/blood pressure or cause drowsiness. Ask your pharmacist about the safe use of those products.

See also:
What are the possible side effects of Nyquil?

PARACETAMOL: Sensitivity reactions resulting in reversible skin rash or blood disorders may occur. Patients suffering from kidney or liver disease should take paracetamol under medical supervision.

Dextromethorphan (Nyquil) HYDROBROMIDE: May cause drowsiness, dizziness, excitation, mental confusion and gastro-intestinal disturbances. Should be administered with caution to patients with liver disease and to asthmatic patients. High doses cause respiratory depression.

Doxylamine (Nyquil) SUCCINATE: Doxylamine (Nyquil) Succinate may cause sedation varying from slight drowsiness to deep sleep and including inability to concentrate, lassitude, dizziness, hypotension, muscular weakness and inco-ordination.

Other side effects include gastro-intestinal disturbances such as nausea, vomiting, diarrhoea or constipation and epigastric pain. Doxylamine (Nyquil) Succinate may also produce headache, blurred vision, tinnitus, elation or depression, irritability, nightmares, anorexia, difficulty in micturition, dryness of the mouth, tightness of the chest and tingling, heaviness and weakness of the hands. Symptoms of stimulation may include insomnia, nervousness, tachycardia, tremors, muscle twitching and convulsions.

Large doses may precipitate fits in epileptics. Allergy and dermatological reactions may occur. Blood disorders including agranulocytosis and haemolytic anemia, have been reported. Doxylamine (Nyquil) Succinate may enhance the sedative effect of central nervous system depressants including alcohol barbiturates, hypnotic analgesics, sedatives and tranquillizers.

Effects of anticholinergic drugs such as atropine and tricyclic antidepressants, may be enhanced by the concomitant administration of Doxylamine (Nyquil) Succinate. Doxylamine (Nyquil) Succinate may effect the metabolism of drugs in the liver.

Doxylamine (Nyquil) should be used with care in conditions such as glaucoma and prostatic hypertrophy.

EPHEDRINE SULPHATE: Ephedrine Sulphate may give rise to side-effects such as giddiness headache, nausea, vomiting, sweating, thirst, tachycardia, precordial pain, palpitations, difficulty in micturition, muscular weakness and tremors, anxiety, restlessness and insomnia. Ephedrine Sulphate should be avoided in patients with most types of cardiovascular disease, hypertension, hyperthyroidism, hyperexcitability, phaechromocytoma and closed-angle glaucoma. In patients with prostatic enlargement, it may increase difficulty with micturition. It should be used with caution in patients receiving chloroform, cyclopropane, halothane or other halogenated anaesthetics.

The effects of Ephedrine are diminished by guanethidine, reserpine and probably methyldopa and may be diminished or enhanced by tricyclic antidepressants. Ephedrine may also diminish the effects of guanethidine and may increase the possibility of arrhythmias in digitalised patients.