Optimal Timing for Bilastine 20 mg Administration
Take bilastine 20 mg on an empty stomach—at least 1 hour before or 2 hours after food—to ensure optimal absorption and therapeutic effect. 1
Rationale for Fasting Administration
- Food significantly reduces bilastine absorption, decreasing maximum plasma concentration by approximately 34% and overall drug exposure by 29-33% when taken with meals 2
- Despite this pharmacokinetic interaction, the clinical antihistaminic efficacy remains largely preserved even when taken with food, with only a minor 30-minute delay in onset of wheal inhibition on the first treatment day 2
- At steady state (after 4 days of treatment), the pharmacodynamic effects show no significant difference between fasting and fed conditions 2
Practical Dosing Recommendations
- Standard dosing: 20 mg once daily for adults and adolescents ≥12 years of age 3
- Timing flexibility: Bilastine can be taken at any time of day, but must maintain the fasting requirement 1, 4
- Avoid fruit juice: Grapefruit juice and other fruit juices also interfere with absorption and should be avoided around dosing time 1
Special Populations Requiring No Adjustment
- Renal impairment: No dose adjustment needed regardless of severity (even with GFR ≤30 mL/min/1.73 m²), as the 20 mg dose remains within safety margins despite increased drug exposure 5
- Hepatic impairment: No dose adjustment required, as bilastine undergoes minimal hepatic metabolism 3
- Elderly patients: No dose modification necessary 3
Clinical Considerations
- Rapid onset: Bilastine demonstrates antihistaminic activity within 1 hour of administration under fasting conditions 2
- Duration of action: 14-hour elimination half-life supports once-daily dosing 4
- No sedation: Does not penetrate the central nervous system and shows minimal sedative properties comparable to placebo 4, 3