Second generation over-the-counter antihistamines cause less side effects like drowsiness.
Over-the-counter antihistamines are available in the form of first generation and second generation antihistamines.First generation OTC anti-histamines for allergies (active ingredients and brand names):
Diphenhydramine BenadrylSecond generation OTC anti-histamines for allergies
(active ingredients and brand names):
Indications sneezing, itching, watery eyes and runny nose and hives.
Contraindications discontinue use and seek medical attention if serious allergic reaction occurs.
Cetirizine (Zyrtec): Tablet - 5-10 mg orally once a day depending upon symptom severity. Syrup 5 mg/ 5 mL
Loratadine (Claritin, Tavist), Brompheniramine (Dimetane): Tablet 10mg once daily for adults, 5 mg once daily for children 2 to 5 years.
Chlorpheniramine (Chlor-Trimeton) 4 mg orally every 4 - 6 hrs; sustained-release: 8 or 12 mg orally every 8 - 12 hours. Maximum dose: 24 mg/day.
Diphenhydramine (Benadryl): 25 mg to 50 mg (1-2 capsules) per day for adults and children above 12 years; for children 6 -12 years of age 25 mg (1 capsule)
Side effects drowsiness especially in case of first generation antihistamines, restlessness, nervousness, upset stomach, dry mouth, irritability, difficulty urinating and sometimes blurred vision.
Precautions and Warnings:
Second generation antihistamines are less likely to interact with other drugs like sedatives
Do not use antihistamines in large amounts or for longer than recommended.
Use alcohol cautiously if you are on antihistamines
While taking antihistamines, do not drive or use machinery that could harm you if you are not alert
Consult your doctor before using antihistamines if you have glaucoma, high blood pressure, hyperthyroidism, heart disease, stomach problems, liver disease, kidney disease and diabetes
Inform your healthcare provider if you are pregnant or breastfeeding.
Store in cool, dry place. Protect from heat and light