Efficacy and clinical indications
Bilastine is indicated for symptomatic treatment of allergic rhino-conjunctivitis (seasonal and perennial) and urticaria in adults and adolescents (≥12 years). [1] Loratadine is indicated for symptomatic treatment of allergic rhinitis and chronic idiopathic urticaria in adults and pediatric patients (≥2 years depending on formulation). [2] Both agents are recommended as non-sedating, peripheral H1-antihistamines at labeled doses for the listed indications. [1][2]
Dosing and administration
Bilastine 20 mg is dosed once daily (1 tablet) for adults and adolescents (≥12 years). [1] Bilastine should be taken 1 hour before or 2 hours after intake of food or fruit juice. [1] Loratadine 10 mg is dosed as 1 tablet once daily. [2] Loratadine can be taken without regard to mealtime. [2]
Sedation risk
Bilastine: somnolence occurred in 3.06% of bilastine 20 mg recipients versus 2.86% with placebo in clinical trials. [1] Loratadine: somnolence incidence was 1.2% at the recommended 10 mg daily dose (reported in excess of placebo) in clinical trials. [2] Loratadine has no clinically significant sedative properties in the majority of the population at the recommended dose. [3]
Drug–drug interactions
Bilastine interactions
Food reduces bilastine oral bioavailability by 30%. [1] Grapefruit juice reduces bilastine bioavailability by 30% and the effect may apply to other fruit juices. [1] Ketoconazole and erythromycin increase bilastine exposure (bilastine AUC increased 2-fold; Cmax increased 2–3-fold). [1] Diltiazem increases bilastine Cmax by 50%. [1] Bilastine plus alcohol did not show psychomotor performance potentiation versus alcohol plus placebo. [1] Concomitant intake with lorazepam did not potentiate lorazepam CNS depressant effects. [1] In moderate or severe renal impairment, coadministration with P-gp inhibitors (examples include ketoconazole, erythromycin, cyclosporine, ritonavir, and diltiazem) should be avoided because increased bilastine plasma levels may increase adverse-effect risk. [4]
Loratadine interactions
Alcohol has no potentiating effects on psychomotor performance with loratadine (as measured in psychomotor performance studies). [2] Potential interactions occur with inhibitors of CYP3A4 or CYP2D6 that may elevate loratadine levels and increase adverse events. [2] In controlled studies, increased loratadine plasma concentrations were reported with ketoconazole, erythromycin, and cimetidine, without clinically significant changes including electrocardiographic changes. [2]
Hepatic and renal impairment suitability
Bilastine
No dosage adjustment is required in adults with renal impairment. [1] No dosage adjustment is required in adults with hepatic impairment. [1] In moderate or severe renal impairment, avoidance of bilastine coadministration with P-gp inhibitors is recommended due to increased bilastine exposure. [4]
Loratadine
No dosage adjustments are required in patients with renal insufficiency. [2] No dosage adjustment is required in elderly patients. [2] Patients with severe hepatic impairment should receive a lower initial dose (10 mg every other day) because of reduced clearance. [2]
Pregnancy and breastfeeding suitability
Bilastine
Pregnancy: there are no or limited data in pregnant women. [5] As a precautionary measure, avoidance of bilastine during pregnancy is preferred. [5] Breast-feeding: bilastine excretion in human milk has not been studied. [5] A risk–benefit decision regarding continuation versus discontinuation during breast-feeding is required based on maternal benefit and breastfeeding benefit for the child. [5]
Loratadine
Pregnancy: available human data have not shown increased risk of miscarriage or birth defects, and loratadine is not expected to increase the chance of birth defects. [6] Breast-feeding: loratadine passes into breast milk in small amounts, and loratadine is described as one of the preferred antihistamines during breastfeeding due to lower likelihood of drowsiness than some alternatives. [6] LactMed reports that, because of low milk levels and lack of sedation, maternal loratadine use would not be expected to cause adverse effects in breastfed infants, and the BSACI recommends loratadine at its lowest dose as a preferred choice when an antihistamine is required during breastfeeding. [7]
Comparative considerations for choosing between bilastine and loratadine
Bilastine has higher documented somnolence rates versus placebo (3.06% vs 2.86%) at labeled dosing. [1] Loratadine has somnolence reported at 1.2% (in excess of placebo) at the recommended 10 mg dose. [2] Bilastine has administration constraints with food and fruit juice and clinically important exposure reductions with food and grapefruit juice. [1] Loratadine has no labeled mealtime restrictions and is dosed once daily at 10 mg. [2] Bilastine has exposure increases with ketoconazole/erythromycin and diltiazem, and additional avoidance recommendations apply in moderate or severe renal impairment when P-gp inhibitors are used. [1][4] Loratadine has interaction potential with CYP3A4/CYP2D6 inhibitors that may elevate loratadine levels, but ketoconazole/erythromycin/cimetidine interactions in controlled studies were not associated with clinically significant safety changes. [2] Bilastine is generally positioned as a precautionary “avoid during pregnancy” option with limited pregnancy data, whereas loratadine has more reassuring pregnancy safety information in human data sets. [5][6] Loratadine has more supportive evidence for breastfeeding use with low milk levels and low expected infant sedation risk, whereas bilastine lacks human lactation excretion data. [5][6][7]