Claritin and DayQuil interaction

Can you take Claritin and DayQuil together

What is Claritin

Claritin is a Brand name for antihistamine drug that contains loratadine as an active ingredient. Loratadine is second generation, long-acting, non-sedating antihistamine drug that reduces the effects of natural histamine during allergic reactions in the body.

It is used for relieving the symptoms of hives, skin rash, itching, sneezing, runny nose, watery eyes and other allergy or cold symptoms. Claritin can be also used for the treatment of chronic skin hives and itching.

Claritin D is a product that except loratadine, also contain pseudoephedrine as an active ingredient and it can be used for the treatment of nasal congestion.

Claritin is available in following dosage forms and strengths: solution (5mg/5ml), syrup (1mg), tablet (10mg), chewable tablet (5mg), orally disintegrated tablet (5 and 10mg), capsule and liquid filled capsule (10mg).

Other products on the market containing loratadine are: Alavert, Claritin D, Claritin Reditab, Clear-Atadine, Dimetapp ND, ohm Allergy Relief, QlearQuil All Day & Night, Tavist ND, Wal-itin.


What is DayQuil

DayQuil is a brand name for OTC medication which is used for relieving symptoms of common cold and flu. There are several formulations of DayQuil on the market: DayQuil Cough (liquid dosage form containing dextromethorphan 15mg), DayQuil Cold & Flu (liquid and liquicaps containing dextromethorphan 10mg, acetaminophen 325 mg and phenylephrine 5 mg), DayQuil Severe Cold & Flu (liquid and caplets containing acetaminophen 325 mg, dextromethorphan 10 mg, guaifenesin 200 mg and phenylephrine 5 mg), DayQuil Mucus Control DM (liquid containing dextromethorphan 10 mg and guaifenesin 200 mg) and Dayquil Sinex (liquicaps containing acetaminophen 325 mg and phenylephrine 5 mg and nasal spray containing oxymetazoline HCl 0.05%)

Other Brand names on the market containing similar combination are: NyQuil, Alka-Seltzer Plus Day Cold, Theraflu, Tylenol Alka-Seltzer Plus Day Sinus Congestion, Allergy & Cough, Alka-Seltzer Plus Severe Sinus Congestion & Cough and others.

claritin and dayquil mix

How does Claritin and DayQuil work in the body

Loratadine is a long acting second generation antihistamine. Loratadine has similar pharmacology effects to other antihistamines, but unlike other H1-antagonists, loratidine has more competitive, specific, and selective antagonism properties for H1 receptors.

Exact mechanism of prolonged antihistamine effects is unknown, but it may be because of drug’s slow dissociation from the H1 receptor or because of the formation of its active metabolite desloratidine.

Loratadine does not penetrate blood-brain barrier effectively and has a low affinity for H1-receptors in CNS than other antihistamine drugs. Studies showed that loratadine has a low affinity for cholinergic receptors and does not have any significant alpha-adrenergic antagonist in-vitro activity.

Loratadine can also suppress the release of histamine and leukotrienes mastocytes in animals, and the release of leukotrienes, however the clinical importance of this is still unknown.

Dextromethorphan acts on cough center in medulla by decreasing sensitivity of cough receptors and by interrupting impulse transmission. This compound is an antagonist of NMDA receptor and a non-competitive channel blocker. It is one of the most widely used antitussives.

Guaifenesin acts by reducing the viscosity and increasing the volume of secretions in the trachea and bronchi. By reducing the adhesiveness and viscosity of secretions, guaifenesin increases the mucociliary mechanism efficacy in removing secretions which has been accumulated in the upper and lower airways. Studies have also shown that guaifenesin has muscle relaxant and anticonvulsant properties due to antagonism effects on NMDA receptors.

Pseudoephedrine is sympathomimetic amine with direct action on the adrenergic receptor system. The vasoconstriction is produced after α-adrenergic receptors activation that are located on the muscles lining of the walls of blood vessels.

The constricted blood vessels allow less fluid to leave the blood vessels and enter the nose, throat and sinuses, so results are: decreased inflammation of nasal membranes and decreased mucus production.

In bronchi, due to β2-adrenergic receptors activation, this substance can produce relaxation of smooth muscle, causing bronchial dilation and decreasing congestion and breathing difficulties.

Acetaminophen is highly selective COX-2 inhibitor that inhibits prostaglandin synthesis. It can inhibit COX-2 in CNS. Acetaminophen also acts on the hypothalamic heat regulating centers to produce antipyresis.

Phenylephrine is sympathomimetic with direct action on the adrenergic receptor system. The vasoconstriction is produced after α-adrenergic receptors activation.

Can patients take Claritin and DayQuil together

It is not recommendable to take Claritin and DayQuil together, and patients should not take them at the same time. Dayquil products are for colds and flu, and patients should not take antihistamines such as Claritin when they have a cold anyway.

Antihistamines can slow the clearance of secretions and they may prolong viral respiratory. Also, both medications may have antihisstamines and decongestants already, so there is a risk that patient may duplicate the doses of these drugs.

The best option is to try just taking the Dayquil and if it is not sufficient, then patient should go to allergist who may prescribe Claritin instead of DayQuil or some other therapy.

The table below shows side effects after Claritin and DayQuil administration in recommendable doses. The incidence can be significantly increased if these drugs are overdosed or taken together.

Very common side effects >10% Headache (12%)
Common side effects 1-10% Drowsiness (8%) Somnolence (8%), Asthma symptoms (3-7%), Nervousness (4%), Dysphonia (4%), Hyperkinesia (3%), Fatigue (3-4%), Hyperkinesia (3%), Dry mouth (3%), Dysphonia (2%), Malaise (2%), Upper Respiratory Tract Infection (2%), Conjunctivitis (2%), Abdominal pain (2%)
Frequency Not Defined Hypertension, Tachycardia, Hypotension, Reflex tachycardia, Severe peripheral and visceral vasoconstriction, Tremor, Dizziness, Excitability, Headache, Sedation, Sleepiness, Restlessness, Dermatologic rash, Increased appetite, Xerostomia, Anemia, blood dyscrasias (neutropenia, pancytopenia, leukopenia), Bilirubin and alkaline phosphatase may increase, Urinary retention, Rash, Itching, Hives.

Special precautions and warnings during Claritin and DayQuil administration:

  • Patients should tell their doctor and pharmacist if they are allergic to Claritin or DayQuil, or any other medications, or any of the active or no active ingredients in Claritin and DayQuil products.
  • Patients should tell their doctor and pharmacist what prescription and nonprescription medicines, nutritional supplements, herbal products or vitamins, they are taking or plan to take. Patients shouldn’t use DayQuil if they have used MAO inhibitors drugs such as furazolidone (Furoxone), phenelzine (Nardil), isocarboxazid (Marplan), selegiline (Eldepryl, Emsam, Zelapar), rasagiline (Azilect), or tranylcypromine (Parnate) in the last 14 days. Drug interactions can occur, leading to serious side effects.
  • Patients should also limit alcoholic beverages while using these drugs.
  • DayQuil can make patients dizzy or drowsy. They should not drive, use machinery, or do any activity that requires alertness.
  • Patients should avoid these medications if they also take caffeine pills, diet pills, or other stimulants. Taking decongestants (pseudoefedrine, phenylephrine) together with stimulants can increase the risk of unpleasant side effects.
  • Medicines such as sedatives, sleeping pills, narcotic pain medicines, medicine for seizures, anxiety or depression, and muscle relaxers can add sedation and sleepiness that can be also caused by dextromethorphan, phenylephrine and pseudoephedrine.
  • Women should tell the doctor if they are pregnant, plan to become pregnant, or are breastfeeding. These drugs shouldn’t be used during pregnancy and breastfeeding.
  • Patients should tell their doctor if they have or have ever had asthma or some liver or kidney disease.
  • If patients have phenylketonuriathey should know that some orally disintegrated products may contain aspartame that forms phenylalanine in the body.
  • Children younger than 4 years should also avoid these medicines. These medicines shouldn’t be taken for longer than 7 days in a row.
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