Dosing and uses of Ketotifen Systemic (Zaditen)
Adult dosage forms and strengths
Systemic formulation not commercially available in the United States
Not for adults
Other Indications & Uses
Adjunct treatment of mild atopic asthma in children
Pediatric dosage forms and strengths
Systemic formulation not commercially available in the United States
Atopic Asthma
>3 years old: 1 mg PO BId
6 months old-3 years old: 0.05 mg/kg PO BId
Start with 1/2 dose, increase to full dose within 5 days
Not for acute attacks
Ketotifen Systemic (Zaditen) adverse (side) effects
1-10%
Weight gain (5.3%)
Rash (4%)
Respiratory infection (4%)
Abdominal pain (1.3%)
Increased appetite (1.3%)
Epistaxis (1.3%)
Puffy eyelid (1.3%)
Sleep disturbance (1.3%)
Other ADRs are equal to or less than placebo
Warnings
Contraindications
Hypersensitivity
Sensitivity to benzoate compounds
Cautions
Do not reduce immediately symptomatic & prophylactic antiasthmatic drugs (xanthine derivatives, 2-agonists, sodium cromoglycate, corticosteroids) when starting treatment with ketotifen
History of epilepsy
Perform thrombocyte counts in pts taking oral antidiabetic agents concomitantly
May potentiate the effects of sedatives, hypnotics, antihistamines & alcohoL
Pregnancy and lactation
Pregnancy category: safety not established; weigh risk/benefit
Lactation: secreted into breast milk, do not use if breastfeeding
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be 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.
Pharmacology of Ketotifen Systemic (Zaditen)
Half-life: 1 hour
Bioavailbility: 50%
Protein Bound: 75%
Absorption: rapid; 60%
Metabolites: inactive ketotifen-N-glucuronide
Excretion: urine: 1% unchanged drug, 60-70% as metabolites
Mechanism of action
Nonbronchodilator which inhibits effects of certain inflammatory mediators & exerts antiallergic activity
