Cold, allergies and flu have all become common ailments in our lives. You may take an over-the-counter drug to treat many of these minor health conditions. Nyquil is one such drug. It is widely used for the treatment of flu and cold. But, do you know how long nyquil lasts in your body? Read on for more details on this.

Over-the-counter drugs are usually considered to have very minimal or nil hangover effects. But, it becomes essential to know how long a popular OTC drug like nyquil lasts in your body. Nyquil is a drug widely used for the treatment of signs of common cold or flu. The most common signs of these medical conditions are cough, soreness of throat, runny nose, sneezing, pains and headache. Nyquil is sold as a pill as well as in a liquid form. Between these two forms, liquid version is more popular.

There are three very active items in nyquil namely, doxylamine (an antihistamine that works by reducing allergic symptoms such as itchiness, soreness of throat, runny nose, etc.; as the name indicates this drug is an effective blocker of allergy-causing histamines), acetaminophen (this substance is a reliever of pain & fever; its main function is to decrease temperature of your body) and dextromethorphan (this is a suppressant of coughs; it works on your brain and reduces your need to cough). Nyquil has the combined strengths of all these three active chemicals. You may need to remember that this drug is not used for the case management of respiratory disorders or breathing difficulties (commonly experienced as part of asthma or bronchitis).

One of its most chemicals doxylamine stops the effects of certain histamines. The natural outcome of this activity is sleepiness. This active chemical is a standard item in all formulations of nyquil. Hence, regardless of the various formulations and secondary inputs added to Nyquil, sleepiness is a constant side effect caused by this drug.

Side-effects of nyquil and precautions needed

Many cold or cough products (especially those sold as OTC drugs) have limitations while administered onto kids. Hence, such drugs are rarely given to children less than 7 years of age. Also, a few long-action pills are not administered onto children aged 13 years and below. You are hence advised to talk to your treating doctor (or a qualified and trained pediatrician) for more inputs on this front.

The common side effects caused by intake of nyquil are – blurring of eyesight, dizziness, nausea, etc. You are advised to seek medical help if these signs continue for a longer time. An overdose of this drug may cause agitation, nervousness, confusion, passing out, etc. In some instances, severe breathing problems have been reported. Among children, an overdose can trigger excessive dizziness and convulsions.

Before starting to take nyquil, it is recommended to keep the treating doctor informed about your medical history and your family’s clinical history. Tell your physician if you have medical conditions such as mood shifts, incontinence, convulsions, respiratory problems, etc. Also, inform your pharmacist and treating doctor if you have renal disorders, diabetes, cardiac disorders, eye problems such as glaucoma, hormonal issues (like increased production of thyroid), etc.

How long does nyquil last in your body?

Nyquil is used when you develop symptoms such as headache and runny nose. The medication may begin its action within 30 minutes. As sleep is a good medicine for flu or common cold, nyquil puts you to sleep. Also, you may be tossing and turning on your bed when you are down with flu; this drug mainly focuses on getting your body to rest through deep sleep. Above all, nyquil is prescribed as a drug to be used during nights. So, it naturally contains substances that actively boost deep sleep.

However, the drug’s effects are found to last longer. This can be experienced through a feeling of drowsiness and tired eyes – as soon as you are out of your bed. You may also find your eyesight becoming blurred. These effects may show up regardless of how many hours you slept.

Number of hours a drug’s residual effects last is best known through half-life of its key chemicals. (1) Dextromethorphan (cough suppressant) has a half-life of about 4 to 5 hours. This chemical may take more than 15 to 30 hours for its complete discharge from your system; (2) Acetaminophen (reducer of fevers) – Its half-life is noted as 2.5 hours. Hence, it may take almost 24 hours to complete get rid of it from your body and (3) Doxylamine (works against allergy-triggering histamines) may be discharged in nearly 11 hours.

Based on the above, you may note most of its chemicals are discharged from the body in about 12 hours. Anti-histaminic substances are the last to get out of your body; these are known to induce sleep as they fight allergens. In some formulations, manufacturers may add substances like pseudoephedrine, which may consume longer times to get out of your system. So, for all traces of this drug to be removed from your body, it may take upto 3 days from the time of your last dosage.

On the contrary, if acute dizziness and confusion is observed for more than 3 days, do not hesitate to seek medical help immediately. You can contact 911 or a local poison control center to take medical care at the earliest possible time.


Other factors influencing the aftereffects of nyquil

Half-lives are only one side of the story. Nyquil’s sleep inducing effects may also be influenced by other factors. The most common factors include – your body mass index (BMI), rate of metabolism, age, gender, intensity of dosage of nyquil (both quantum of doses as well as time interval between doses), foods eaten and the other medications administered while taking this drug.

Doctors may tell patients to expect a mild blurring of eyesight as well as extremely tired eyes. To be on the safer side, you may need to give at least six to seven hours from time of the last dose to come back to a normal state. After the lapse of this time, you will be ready to start work. But, for about twelve hours from your last dose of nyquil never do stressful work. Also, keep away from driving or operating heavy machinery during this period.


Other related precautions

Nyquil may interact with a few other medications. Co-administration of drugs such as isocarboxazid, selegiline and methylene (blue) needs to be avoided. These drugs aside, topical anti-allergic creams and lotions may also interact with nyquil. Stay clear of drugs such as ketoconazole or diphenhydramine lotion or sprays while taking this drug. A few types of antihistamine drugs (like cetirizine, etc.) are also to be avoided.

There are a few medications that may cause dizziness. These medicines are to be avoided while consuming nyquil. These are sleep inducing drugs (such as lorazepam, alprazolam, etc.) and muscle relaxing medications (like cyclobenzaprine, etc.).

Your doctor may ask you to stop taking alcohol or minimize its consumption while taking this drug. You may also need to inform your treating doctor if you are consuming opioids, drugs for relieving pains or coughs – such as hydrocodone, etc.

In essence, nyquil is widely used to treat symptoms of flu. Three (3) active substances in nyquil help bring about a cure – these are doxylamine (an antihistamine), acetaminophen (reliever of fever) and dextromethorphan (suppressant of coughs). Side effects triggered by intake of nyquil include – dizziness, nausea, etc. A likely overdose can lead to confusion and passing out. In children, an overdose may cause convulsions. Before starting to take nyquil, tell your doctor if you experience mood shifts, incontinence, convulsions, respiratory problems, etc. Also, share details about renal disorders, diabetes, cardiac disorders, eye problems – such as glaucoma, hormonal issues (like increased production of thyroid), etc. – if any.

Based on half-lives of active items, chemicals in nyquil are found to get eliminated in about 12 hours. However, anti-histamine chemicals are the last to be discharged from your body. As these chemicals are known for their sleep inducing properties, the drowsy effects last for slightly more than 12 hours. But, it may take upto 3 full days for the entire traces of nyquil’s various constituents to be eliminated from your system. The three days may be counted from the time of your last dosage of nyquil. But, if drowsiness or dizziness is acute and are observed to persist longer than 3 days, do not hesitate to seek medical help immediately. You can contact 911 or call an emergency hotline number to avail needful assistance without any possible delay.


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