Antihistamines

Children >/= 6 years and Adults:
Chronic urticaria, perennial or seasonal allergic rhinitis: 5-10 mg once daily, depending upon symptom severity

Elderly Initial: 5 mg once daily; may increase to 10 mg/day. Note: Manufacturer recommends 5 mg/day in patients >/= 77 years of age.

Dosage adjustment in renal/hepatic impairment:
Children <6 years: Cetirizine use not recommended
Children 6-11 years: <2.5 mg once daily
Children >/= 12 and Adults:
Clcr 11-31 mL/minute, hemodialysis, or hepatic impairment: Administer 5 mg once daily
Clcr<11 mL/minute, not on dialysis: Cetirizine use not recommended.

Supplied:
Syrup, as hydrochloride: 5 mg/5 mL (120 mL, 480 mL) [banana-grape flavor]
Tablet, as hydrochloride: 5 mg, 10 mg
Tablet, chewable, as hydrochloride: 5 mg, 10 mg [grape flavor]

Mechanism of Action
Desloratadine is a long-acting tricyclic histamine antagonist with selective H1-receptor histamine antagonist activity. Receptor binding data indicate that at a concentration of 2–3 ng/mL (7 nanomolar), desloratadine shows significant interaction with the human histamine H1-receptor. Desloratadine inhibited histamine release from human mast cells in vitro.

Results of a radiolabeled tissue distribution study in rats and a radioligand H1-receptor binding study in guinea pigs showed that desloratadine did not readily cross the blood brain barrier.
.

Dosing: Oral:   Children:
6-11 months: 1 mg once daily
12 months to 5 years: 1.25 mg once daily
6-11 years: 2.5 mg once daily

Children >/= 12 years and Adults: 5 mg once daily

Supplied
Syrup (Clarinex®): 0.5 mg/mL (480 mL) [bubble gum flavor]

Tablet (Clarinex®): 5 mg

Tablet, orally-disintegrating (Clarinex® RediTabs®): 5 mg [contains phenylalanine 1.75 mg/tablet]

Mechanism of Action
Fexofenadine hydrochloride, the major active metabolite of terfenadine, is an antihistamine with selective peripheral H1-receptor antagonist activity. Both enantiomers of fexofenadine hydrochloride displayed approximately equipotent antihistaminic effects. Fexofenadine hydrochloride inhibited antigen-induced bronchospasm in sensitized guinea pigs and histamine release from peritoneal mast cells in rats. The clinical significance of these findings is unknown. In laboratory animals, no anticholinergic or alpha1-adrenergic blocking effects were observed. Moreover, no sedative or other central nervous system effects were observed. Radiolabeled tissue distribution studies in rats indicated that fexofenadine does not cross the blood-brain barrier.

Dosage - Oral:
Children 6-11 years: 30 mg twice daily

Children >/= 12 years and Adults:
Seasonal allergic rhinitis: 60 mg twice daily or 180 mg once daily
Chronic idiopathic urticaria: 60 mg twice daily

Supplied
Tablet, as hydrochloride: 30 mg, 60 mg, 180 mg

Children >/= 6 years and Adults: 10 mg once daily

Elderly: Peak plasma levels are increased; elimination half-life is slightly increased; specific dosing adjustments are not available

Dosage adjustment in renal impairment: Clcr </= 30 mL/minute:
Children 2-5 years: 5 mg every other day
Children >/= 6 years and Adults: 10 mg every other day

Supplied
Syrup (Claritin®): 1 mg/mL (120 mL) [contains sodium benzoate; fruit flavor]
Tablet (Alavert™, Claritin®, Claritin® Hives Relief; Tavist® ND): 10 mg
Tablet, rapidly-disintegrating: 10 mg
Alavert™: 10 mg [contains phenylalanine 8.4 mg/tablet]
Claritin® RediTabs®: 10 mg [mint flavor]
Dimetapp® Children's ND: 10 mg [contains phenylalanine 8.4 mg/tablet]

Claritin-D 24 Hour Extended Release Tablets should generally be avoided in patients with hepatic insufficiency. Patients with renal insufficiency (GFR <30 L/min) should be given a lower initial dose (one tablet every other day) because they have reduced clearance of loratadine and pseudoephedrine. Patients who have a history of difficulty in swallowing tablets or who have known upper gastrointestinal narrowing or abnormal esophageal peristalsis should not use this product.

Initial U.S. Approval:  2013

Mechanism of Action: Carbinoxamine is an H1 receptor antagonist (antihistamine) that exhibits anticholinergic (drying) and sedative properties.
Antihistamines compete with histamine for receptor sites on effector cells.

INDICATIONS AND USAGE:
Karbinal ER (carbinoxamine maleate) Extended-release Oral Suspension is an H1 receptor antagonist indicated for the symptomatic treatment of:

Seasonal and perennial allergic rhinitis (1)
Vasomotor rhinitis (1)
Allergic conjunctivitis due to inhalant allergens and foods (1)
Mild, uncomplicated allergic skin manifestations of urticaria and angioedema (1)
Dermatographism (1)
As therapy for anaphylactic reactions adjunctive to epinephrine and other standard measures after the acute manifestations have been controlled (1)
Amelioration of the severity of allergic reactions to blood or plasma (1)

DOSAGE AND ADMINISTRATION
The dosage of Karbinal ER should be individualized based on the severity of the condition and the response of the patient. Start with lower doses and increase as needed and tolerated.
Administer Karbinal ER by the oral route only. Measure Karbinal ER with an accurate milliliter measuring device. A household teaspoon is not an accurate measuring device and could lead to overdosage. A pharmacist can provide an appropriate measuring device and can provide instructions for measuring the correct dose. [see Warnings and Precautions (5.5)]

Adults and Adolescents 12 years of age and older:
7.5 mL to 20 mL (6 to 16 mg) every 12 hours

Children 2 to 11 years of age (approximately 0.2 to 0.4 mg/kg/day):
2 to 3 years: 3.75 mL to 5 mL (3 to 4 mg) every 12 hours
4 to 5 years: 3.75 mL to 10 mL (3 to 8 mg) every 12 hours
6 to 11 years: 7.5 mL to 15 mL (6 to 12 mg) every 12 hours

HOW SUPPLIED:  Extended-release oral suspension containing 4 mg carbinoxamine maleate per 5 mL

Adults and children 12 years of age and older: take 1 tablet every 12 hours, not more than 2 tablets in 24 hours unless directed by a doctor.

Dosage - Oral: Children:
Allergic conditions: 0.25 mg/kg/day or 8 mg/m 2 /day in 2-3 divided doses or

2-6 years: 2 mg every 8-12 hours (not to exceed 12 mg/day)
7-14 years: 4 mg every 8-12 hours (not to exceed 16 mg/day)

Migraine headaches: 4 mg 2-3 times/day

Children >/= 12 years and Adults: Spasticity associated with spinal cord damage: 4 mg at bedtime; increase by a 4 mg dose every 3-4 days; average daily dose: 16 mg in divided doses; not to exceed 36 mg/day

Children >13 years and Adults: Appetite stimulation (anorexia nervosa): 2 mg 4 times/day; may be increased gradually over a 3-week period to 8 mg 4 times/day

Adults:
Allergic conditions: 4-20 mg/day divided every 8 hours (not to exceed 0.5 mg/kg/day)
Cluster headaches: 4 mg 4 times/day
Migraine headaches: 4-8 mg 3 times/day

Supplied
Syrup, as hydrochloride: 2 mg/5 mL (473 mL) [contains alcohol 5%; mint flavor]
Tablet, as hydrochloride: 4 mg

Adults: 50-100 mg every 4-6 hours, not to exceed 400 mg/day

Supplied
Caplet (TripTone®): 50 mg
Tablet (Dramamine®): 50 mg
Tablet, chewable (Dramamine®): 50 mg [contains phenylalanine 1.5 mg/tablet and tartrazine; orange flavor]

Diphenhydramine hydrochloride in the injectable form has a rapid onset of action. Diphenhydramine hydrochloride is widely distributed throughout the body, including the CNS. A portion of the drug is excreted unchanged in the urine, while the rest is metabolized via the liver. Detailed information on the pharmacokinetics of diphenhydramine hydrochloride injection is not available.

Dosing- Children:   Oral, I.M., I.V.:
Treatment of moderate to severe allergic reactions: 5 mg/kg/day or 150 mg/m 2 /day in divided doses every 6-8 hours, not to exceed 300 mg/day

Minor allergic rhinitis or motion sickness:
2 to <6 years: 6.25 mg every 4-6 hours; maximum: 37.5 mg/day
6 to <12 years: 12.5-25 mg every 4-6 hours; maximum: 150 mg/day
>/= 12 years: 25-50 mg every 4-6 hours; maximum: 300 mg/day

Night-time sleep aid: 30 minutes before bedtime:
2 to <12 years: 1 mg/kg/dose; maximum: 50 mg/dose
>/= 12 years: 50 mg

Oral: Antitussive:
2 to <6 years: 6.25 mg every 4 hours; maximum 37.5 mg/day
6 to <12 years: 12.5 mg every 4 hours; maximum 75 mg/day
>/= 12 years: 25 mg every 4 hours; maximum 150 mg/day

 I.M., I.V.: Treatment of dystonic reactions: 0.5-1 mg/kg/dose

Adults:
Oral: 25-50 mg every 6-8 hours
Minor allergic rhinitis or motion sickness: 25-50 mg every 4-6 hours; maximum: 300 mg/day
Moderate to severe allergic reactions: 25-50 mg every 4 hours, not to exceed 400 mg/day
Nighttime sleep aid: 50 mg at bedtime

 I.M., I.V.: 10-50 mg in a single dose every 2-4 hours, not to exceed 400 mg/day
Dystonic reaction: 50 mg in a single dose; may repeat in 20-30 minutes if necessary

Topical: For external application, not longer than 7 days

Supplied
Elixir, as hydrochloride: 12.5 mg/5 mL (480 mL)
Caplet, as hydrochloride: 25 mg, 50 mg
Capsule, as hydrochloride: 25 mg, 50 mg
Injection, solution, as hydrochloride: 50 mg/mL (1 mL)
Solution, topical, as hydrochloride [spray] (Benadryl® Itch Stopping Extra Strength): 2% (60 mL) [contains zinc acetate 0.1%]
Tablet, chewable, as hydrochloride (Benadryl® Children's Allergy): 12.5 mg [contains phenylalanine 4.2 mg/tablet; grape flavor]
Tablet, orally-disintegrating, as citrate (Benadryl® Children's Allergy Fastmelt®): 19 mg [equivalent to diphenhydramine hydrochloride 12.5 mg; contains phenylalanine 4.5 mg/tablet and soy protein isolate; cherry flavor]

Intravenous, intra-arterial, and subcutaneous administration are not recommended since thrombosis and digital gangrene can occur

Administer I.M. into deep muscle (preferred route of administration). Due to the possibility of orthostatic hypotension, I.V. administration is not the preferred route. Solution for injection may be diluted in 25-100 mL NS or D5W (maximum concentration of 25 mg/mL) and infused over 15-30 minutes at a rate </= 25 mg/minute.

[Supplied: 25, 50 mg/ml Injection. 12.5, 25, 50mg suppository. 10 mg/5 ml Syrup. 10, 25 , 50mg Tablet]