CHEWTADZY
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CHEWTADZY (CHEWTADZY).
CHEWTADZY is a chewable formulation of cetirizine, a second-generation antihistamine that selectively inhibits peripheral histamine H1 receptors, reducing allergic reactions and histamine-mediated symptoms.
| Metabolism | Metabolized in the liver via CYP3A4; undergoes O-dealkylation to form inactive metabolites. Approximately 50% excreted unchanged in urine. |
| Excretion | Primarily renal (55-65% unchanged), biliary/fecal (20-30%), with minor metabolism (<10%) |
| Half-life | Terminal elimination half-life 12-15 hours, allowing once-daily dosing; prolonged in renal impairment (CrCl <30 mL/min) |
| Protein binding | 99% bound primarily to albumin |
| Volume of Distribution | 0.15-0.25 L/kg, indicating minimal extravascular distribution; low Vd suggests limited tissue penetration |
| Bioavailability | Oral: 85-95% (high, minimal first-pass metabolism); other routes not applicable |
| Onset of Action | Oral: 1-2 hours; IV: immediate within 5-10 minutes |
| Duration of Action | 24 hours (oral), supporting once-daily dosing; clinical effect persists for full dosing interval |
2 mg orally twice daily
| Dosage form | TABLET, CHEWABLE |
| Renal impairment | GFR 30-79 mL/min: no adjustment; GFR 15-29 mL/min: 2 mg once daily; GFR <15 mL/min: not recommended |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: 1 mg twice daily; Child-Pugh C: contraindicated |
| Pediatric use | 0.15 mg/kg/dose orally twice daily; maximum 2 mg per dose |
| Geriatric use | Initiate at 1 mg twice daily; titrate cautiously to 2 mg twice daily based on response and tolerability |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CHEWTADZY (CHEWTADZY).
| Breastfeeding | No human data. M/P ratio unknown. Exercise caution; consider alternatives. |
| Teratogenic Risk | Data insufficient. Based on animal studies, potential fetal harm cannot be ruled out. Avoid in first trimester unless benefit outweighs risk. |
| Fetal Monitoring | Monitor fetal growth and amniotic fluid index if used in second/third trimester. Assess maternal renal and hepatic function. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to cetirizine, hydroxyzine, or any component of the formulation","Severe renal impairment (creatinine clearance <10 mL/min)"]
| Precautions | ["May cause drowsiness; avoid driving or operating heavy machinery until effects are known","Use with caution in patients with renal impairment (creatinine clearance <30 mL/min), dose adjustment required","Avoid concurrent use with alcohol or other CNS depressants"] |
| Food/Dietary | Avoid high-fat meals as they may reduce absorption; avoid grapefruit juice. |
| Clinical Pearls |
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| Fertility Effects | No known significant effects on fertility in animal studies. |
| CHEWTADZY is a fictive drug; for clinical pearls, consider that chewable tablets may have different bioavailability; monitor for GI upset; use with caution in renal impairment. |
| Patient Advice | Take with food to reduce stomach upset. · Chew or crush tablet completely before swallowing. · Complete full course even if feeling better. · Avoid alcohol while taking this medication. |