What's the best time of day to take ZYRTEC®? Any time of day works. And ZYRTEC® will continue to work for 24 hours.
For many people with allergies, symptoms are the worst around 4 a.m. to 6 a.m. Taking an antihistamine at bedtime may help you or your child feel better in the morning during allergy season.
Official answer. Cetirizine can be taken at any time of the day. In most people it is non-sedating, so they take it in the morning. However, a percentage of people do find it to be sedating so if it does make you drowsy it is best to take it in the evening.
The Journal of Clinical Sleep Medicine in its guidelines for sleep medications does not recommend the use of antihistamines for chronic insomnia. Sedating antihistamines can lead to dry mouth, constipation, retention of urine in the bladder, blurred vision and a drop of blood pressure upon standing.
Zyrtec-D (cetirizine / pseudoephedrine) relieves allergies and congestion without causing daytime sleepiness, but it can keep you up at night.
Drowsiness, tiredness, and dry mouth may occur. Stomach pain may also occur, especially in children. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
Cetirizine is a second-generation antihistamine that crosses the blood–brain barrier, has been previously associated with insomnia and nocturnal awakenings, and can cause tolerance with long-term use.
To sum it up, all first-generation H1 antihistamines should be taken close to bedtime or when you're able to sleep. Second-generation H1 antihistamines and H2 blockers can typically be taken at any time of the day. One exception to this is cetirizine, which can cause drowsiness for up to 14% of those who take it.
Newer antihistamines like cetirizine (Zyrtec), desloratadine (Clarinex), fexofenadine (Allegra), levocetirizine (Xyzal), and loratadine (Claritin, Alavert), may be better options and are less likely to cause drowsiness.
Is it safe to take Zyrtec every day? Yep. "When taken in the recommended doses, antihistamines can be taken daily. This is especially true with Zyrtec, since it doesn't show decreasing effectiveness if used daily," says Sima Patel, MD, an allergist at New York Allergy & Sinus Centers.
by Drugs.com
The elimination half-life of Zyrtec is between 8 to 9 hours. It takes approximately 5.5 x elimination half-life for a medicine to be cleared from your system. For Zyrtec this is 5.5 x 9 hours which is about 2 days.
Adults and children 6 years and older Chew and swallow 2 tablet (10 mg) once daily; do not take more than 1 tablet (10 mg) in 24 hours.
While it is just now showing up in the FDA Enforcement report, Perrigo initiated the recall of the antihistamine in late September after it found that the products potentially contained an impurity.
Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: difficulty urinating, fast/irregular/pounding heartbeat, shaking (tremor), mental/mood changes (such as anxiety, confusion, nervousness, restlessness), weakness.
Postnasal drip caused by allergies can be managed with OTC antihistamines and decongestants. Note that older antihistamines like Benadryl and Chlor-Trimeton can actually thicken mucus; instead, try Claritin, Alavert, Allegra, Zyrtec, Xyzal or Clarinex.
Once-daily antihistamines, such as Claritin, reach their peak eight to 12 hours after you take them, so using them at dinnertime or before bed means better control of morning symptoms.
To help you sleep, you'll usually take diphenhydramine 20 minutes before you go to bed. It normally takes about 30 minutes to work. Common side effects include feeling sleepy, dizzy or unsteady on your feet. You may also have difficulty concentrating and have a dry mouth.
Whether your allergy symptoms are a result of dust and pet dander or other allergens, the symptoms usually get worse at night the moment you lie down. This is because whatever was clogging your nasal passages will flow into your upper airway when you lie down flat.
You should not use Zyrtec-D if you have narrow-angle glaucoma, severe high blood pressure (hypertension), severe coronary artery disease, if you are unable to urinate, or if you are allergic to hydroxyzine (Atarax, Vistaril). Do not use this medicine if you have taken an MAO inhibitor in the past 14 days.
Downsides
A headache, sore throat, abdominal pain, fatigue, drowsiness, or coughing. Other side effects are uncommon. Stop using Zyrtec if you develop an allergy to Zyrtec. Generally does not cause drowsiness, although more likely to do so at higher dosages.
Zyrtec may interact with other medicines that make you sleepy (such as other cold or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for seizures, depression, or anxiety). Tell your doctor all medications and supplements you use.
Most antihistamines are known to cause drowsiness during the day. This may be a problem for people who operate heavy machinery or otherwise must remain alert. These drugs also aren't effective for severe anxiety or depression, and they're not a long-term treatment for any anxiety disorder.
Even so, newer antihistamines like Allegra and Zyrtec are known to cause side effects like nausea, diarrhea, headache, back pain, and lethargy. In recent years, another side effect has been added to the list: weight gain.
Antihistamines like diphenhydramine (Benadryl) and cetirizine (Zyrtec) aren't known to raise blood pressure when used alone. Antihistamines are part of many combination over-the-counter (OTC) cough and cold products. They may be combined with a medication that can raise your blood pressure.