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Home > Drug Category > Allergy Medication > Reactine and Equivalent

Reactine Information

Reactine (cetirizine) is a second-generation antihistamine widely used to relieve the symptoms of various allergies. It is highly effective in treating seasonal allergies, such as hay fever, as well as perennial allergies caused by allergens like dust mites and pet dander. The symptoms it relieves include sneezing, a runny nose, watery eyes, and an itchy nose and throat. Reactine is also indicated for the treatment of chronic idiopathic urticaria (hives) and the associated itching. Unlike older, first-generation antihistamines, Reactine is considered non-drowsy at recommended doses. However, some individuals may still experience mild sedation.

The mechanism of action for cetirizine involves the selective blocking of the histamine H1 receptor. Histamine is a key chemical released by the body during an allergic reaction, and its interaction with H1 receptors is responsible for the classic symptoms of allergies. By blocking these receptors, Reactine prevents histamine from triggering the allergic response, thereby reducing inflammation and symptoms. It has a high affinity for the H1 receptor and a rapid onset of action, with effects often noticed within one hour. Because it is a second-generation antihistamine, it does not readily cross the blood-brain barrier at therapeutic doses, which is why it causes significantly less sedation than first-generation antihistamines like diphenhydramine. In Canada, Reactine is available over-the-counter in various formulations, including tablets, chewable tablets, and liquid gels. The standard dose for adults and children 12 years of age and older is 10 mg once daily. For children aged 6 to 11, the dose is typically 5 mg to 10 mg once daily. It provides 24-hour relief, making a once-daily dose convenient for most patients. It can be taken with or without food, as food does not significantly impact its absorption or effectiveness.

Reactine Side Effects

While Reactine is generally well-tolerated, some individuals may still experience side effects. The most common side effects reported are often mild and include headache, dizziness, and mild drowsiness or fatigue. Other less common side effects can include dry mouth, stomach pain, or a sore throat. These effects are usually temporary and may go away as your body adjusts to the medication.

However, more serious side effects can occur, although they are rare. If you experience any of the following, you should stop taking the medication and seek immediate medical attention:

• Paradoxical Central Nervous System Effects: While rare, some individuals may experience a paradoxical reaction to cetirizine, which can lead to restlessness, agitation, or irritability, particularly in children. In some cases, this may be accompanied by vivid dreams or nightmares.

• Hypersensitivity Reactions: Though rare, a severe allergic reaction to Reactine is possible. Symptoms of a severe allergic reaction may include a rash, hives, swelling of the face, lips, or tongue, and difficulty breathing.

• Severe Drowsiness: Although marketed as non-drowsy, some individuals, especially at higher doses or when combined with other central nervous system depressants, may experience significant and incapacitating drowsiness. This can be dangerous when driving or operating machinery.

Reactine Precautions

Before taking Reactine, it is essential to consult a healthcare provider, especially if you have a history of kidney or liver disease, as a lower dose may be necessary. The product monograph recommends a lower dose for individuals with moderate to severe renal impairment. While generally considered non-drowsy, some individuals may still experience dizziness or drowsiness. It is essential to know how the medication affects you before driving or operating heavy machinery, as impaired mental alertness is a possibility. Alcohol and other central nervous system depressants, such as sedatives or tranquillizers, can increase the sedative effects of Reactine, so concurrent use should be avoided. If you are pregnant or breastfeeding, you should discuss the use of Reactine with your doctor. The official product monograph recommends avoiding use during the first trimester of pregnancy and while breastfeeding unless the benefits outweigh the potential risks. Reactine is approved for use in adults and children 6 years of age and older. It is not recommended for children under 6 years of age unless directed by a healthcare professional. You should also be cautious if you have a known allergy to any of its ingredients or to hydroxyzine, as cetirizine is a metabolite of hydroxyzine.

Do I need a prescription to order Reactine?

No, a prescription is not required from your physician to order Reactine.