Cetirizine (As Hydrochloride)

Mechanism of Action
Histamine H1-receptor antagonist, competes with histamine on effector cells in the gastrointestinal tract, blood vessels and respiratory tract
Pharmacokinetics
Peak serum time: 1 hr
Excretion: Urine (70%), feces (10%)
Contraindications
• Hypersensitivity to Cetirizine hydrochloride or any of its ingredients
• Hypersensitivity Hydroxyzine
Adverse Reactions
Somnolence, Headache, Fatigue, Dry mouth, Dizziness, Diarrhea, Malaise, Bronchospasm, Vomiting, Epistaxis
Major Drug Interactions
-
Warnings
• Use caution in hepatic and renal impairment
• The elderly may be more sensitive to adverse effects
Recommendations for Patient
• May cause CNS depression, avoid activities requiring mental alertness until accustomed to medication
• Avoid alcohol, sedatives, and tranquilizers, due to increased risk of drowsiness
Pregnancy Considerations
There are no adequate and well-controlled studies in pregnant women
Breastfeeding Considerations
Small occasional doses of cetirizine are acceptable during breastfeeding. Larger doses or more prolonged use may cause drowsiness and other effects in the infant or decrease the milk supply, particularly in combination with a sympathomimetic such as pseudoephedrine.



Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: Maybe acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.