Claritin

Second Generation Antihistamines

Loratadine may be administered without regard to meals.

Rapidly-disintegrating oral tablets (e.g., Alavert orally disintegrating tablets or Claritin Reditabs): Place on tongue; allow to dissolve and then swallow. May be administered with or without water. Store in a dry place at controlled room temperature. Use within 6 months of opening laminated foil pouch, and immediately upon opening an individual tablet blister.

Oral syrup, suspension, or solution (1 mg/ml): Measure dosage using a calibrated measuring device. Suspension formulations may not need to be shaken; check labeling.

seizures / Delayed / Incidence not known
bronchospasm / Rapid / Incidence not known
erythema multiforme / Delayed / Incidence not known
angioedema / Rapid / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
hepatic necrosis / Delayed / Incidence not known

stomatitis / Delayed / 2.0-3.0
conjunctivitis / Delayed / 2.0-2.0
thrombocytopenia / Delayed / 0-1.0
hypertonia / Delayed / Incidence not known
migraine / Early / Incidence not known
constipation / Delayed / Incidence not known
gastritis / Delayed / Incidence not known
hypotension / Rapid / Incidence not known
sinus tachycardia / Rapid / Incidence not known
hypertension / Early / Incidence not known
chest pain (unspecified) / Early / Incidence not known
peripheral edema / Delayed / Incidence not known
palpitations / Early / Incidence not known
supraventricular tachycardia (SVT) / Early / Incidence not known
hemoptysis / Delayed / Incidence not known
dyspnea / Early / Incidence not known
wheezing / Rapid / Incidence not known
depression / Delayed / Incidence not known
amnesia / Delayed / Incidence not known
confusion / Early / Incidence not known
vaginitis / Delayed / Incidence not known
impotence (erectile dysfunction) / Delayed / Incidence not known
urinary retention / Early / Incidence not known
urinary incontinence / Early / Incidence not known
jaundice / Delayed / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
hepatitis / Delayed / Incidence not known
blurred vision / Early / Incidence not known
blepharospasm / Early / Incidence not known

headache / Early / 12.0-12.0
drowsiness / Early / 8.0-8.0
fatigue / Early / 2.0-4.0
diarrhea / Early / 2.0-3.0
otalgia / Early / 2.0-3.0
pharyngitis / Delayed / 2.0-3.0
xerostomia / Early / 3.0-3.0
epistaxis / Delayed / 2.0-3.0
infection / Delayed / 2.0-3.0
rash / Early / 2.0-3.0
abdominal pain / Early / 2.0-2.0
hyperhidrosis / Delayed / Incidence not known
arthralgia / Delayed / Incidence not known
dizziness / Early / Incidence not known
tremor / Early / Incidence not known
hypoesthesia / Delayed / Incidence not known
vertigo / Early / Incidence not known
asthenia / Delayed / Incidence not known
myalgia / Early / Incidence not known
muscle cramps / Delayed / Incidence not known
paresthesias / Delayed / Incidence not known
nausea / Early / Incidence not known
appetite stimulation / Delayed / Incidence not known
dyspepsia / Early / Incidence not known
flatulence / Early / Incidence not known
polydipsia / Early / Incidence not known
hiccups / Early / Incidence not known
anorexia / Delayed / Incidence not known
vomiting / Early / Incidence not known
dysgeusia / Early / Incidence not known
weight gain / Delayed / Incidence not known
syncope / Early / Incidence not known
tinnitus / Delayed / Incidence not known
sinusitis / Delayed / Incidence not known
nasal dryness / Early / Incidence not known
laryngitis / Delayed / Incidence not known
fever / Early / Incidence not known
sneezing / Early / Incidence not known
cough / Delayed / Incidence not known
chills / Rapid / Incidence not known
insomnia / Early / Incidence not known
paranoia / Early / Incidence not known
irritability / Delayed / Incidence not known
libido decrease / Delayed / Incidence not known
anxiety / Delayed / Incidence not known
menorrhagia / Delayed / Incidence not known
breast enlargement / Delayed / Incidence not known
dysmenorrhea / Delayed / Incidence not known
mastalgia / Delayed / Incidence not known
purpura / Delayed / Incidence not known
alopecia / Delayed / Incidence not known
flushing / Rapid / Incidence not known
pruritus / Rapid / Incidence not known
photosensitivity / Delayed / Incidence not known
xerosis / Delayed / Incidence not known
urticaria / Rapid / Incidence not known
urine discoloration / Early / Incidence not known
ocular pain / Early / Incidence not known

Alavert, Allergy Relief, Claritin, Claritin 24 Hour, Claritin Chewable, Claritin Liqui-Gel, Claritin RediTab, Claritin-D 24 Hour, Clear-Atadine, Dimetapp Children's Non-Drowsy Allergy, QlearQuil All Day & All Night Allergy Relief, Quality Choice Allergy Relief Non-Drowsy, Tavist ND

OTC

Oral non-sedating antihistamine
CNS effects are less with loratadine compared to the traditional sedating antihistamines; not associated with QT prolongation
Used in adult and pediatric populations for allergic rhinitis and chronic idiopathic urticaria or other allergic symptoms

10 mg PO once daily. Do not exceed 10 mg/day.

10 mg PO once daily. Do not exceed 10 mg/day.

5 mg PO twice daily or 10 mg PO once daily. Do not exceed 10 mg/day.

5 mg PO twice daily or 10 mg PO once daily. Do not exceed 10 mg/day.

10 mg PO once daily. Do not exceed 10 mg/day.

10 mg PO once daily. Do not exceed 10 mg/day.

5 mg PO once daily. Do not exceed 5 mg/day.

10 mg PO once daily. Do not to exceed 10 mg/day.

10 mg PO once daily. Do not to exceed 10 mg/day.

5 mg PO once daily. Do not to exceed 5 mg/day.

10 mg PO once daily. Do not exceed 10 mg in 24 hours.

10 mg PO once daily. Do not exceed 10 mg in 24 hours.

10 mg/day PO, given as 5 mg PO twice daily or 10 mg once daily. Tablet disintegrates with or without water. Do not exceed 10 mg in 24 hours. 

10 mg PO daily. Do not exceed 10 mg in 24 hours.

5 mg PO daily. Do not exceed 5 mg in 24 hours.

10 mg PO daily. Do not to exceed 10 mg in 24 hours.

5 mg PO once daily. Do not to exceed 5 mg in 24 hours.

10 mg PO once daily has been used. Because allergy control can lead to better asthma control, the American Thoracic Society recommends daily antihistamine therapy in patients with EIB and allergies who continue to have symptoms despite using an inhaled short-acting beta-2 agonist (SABA) before exercise, or in those who require daily (or more frequent) SABA use. Antihistamines should not be used in nonallergic patients with EIB. Available studies demonstrate some reduction in the symptoms of exercise-induced bronchospasm (EIB). Loratadine 10 mg/day significantly reduced the decrease from baseline in FEV-1 following exercise in a randomized, double-blind, placebo controlled trial in asthmatic patients aged 7 to 17 years with allergies.

†Indicates off-label use

For adults and children 6 years and older: Reduce initial dosage to 10 mg PO every other day.
For children 2 to 5 years: Reduce initial dose to 5 mg PO every other day.

CrCl 30 mL/minute or greater: No dosage adjustment needed.
CrCl less than 30 mL/minute: For adults and pediatric patients 6 years and older, reduce initial dosage to 10 mg PO every other day. For children 2 to 5 years, reduce initial dose to 5 mg PO every other day.
 
Intermittent hemodialysis
Loratadine and its active metabolite are not removed by hemodialysis. See dosage for patients with CrCl less than 30 mL/min.

Acetaminophen; Aspirin; Diphenhydramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Caffeine; Pyrilamine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Chlorpheniramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Dextromethorphan; Doxylamine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Diphenhydramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acetaminophen; Pamabrom; Pyrilamine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Acrivastine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Brompheniramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Brompheniramine; Dextromethorphan; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Brompheniramine; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Brompheniramine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Carbinoxamine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Cetirizine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Cetirizine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlophedianol; Dexbrompheniramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorcyclizine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Codeine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Dextromethorphan: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Hydrocodone: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Chlorpheniramine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Clemastine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Cyclizine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Cyproheptadine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Desloratadine: (Major) Desloratadine is the active metabolite of Loratadine. These 2 drugs should not be given at the same time due to the duplication of therapy and the resultant increase in desloratadine concentrations, which may lead to increased CNS or anticholinergic effects.
Desloratadine; Pseudoephedrine: (Major) Desloratadine is the active metabolite of Loratadine. These 2 drugs should not be given at the same time due to the duplication of therapy and the resultant increase in desloratadine concentrations, which may lead to increased CNS or anticholinergic effects.
Dexbrompheniramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Dexbrompheniramine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Dexchlorpheniramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Dimenhydrinate: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Diphenhydramine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Diphenhydramine; Ibuprofen: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Diphenhydramine; Naproxen: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Diphenhydramine; Phenylephrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Doxylamine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Doxylamine; Pyridoxine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Fexofenadine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Fexofenadine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Heparin: (Minor) Antihistamines may partially counteract the anticoagulant actions of heparin, according to the product labels. However, this interaction is not likely of clinical significance since heparin therapy is adjusted to the partial thromboplastin time (aPTT) and other clinical parameters of the patient.
Hydroxyzine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Levocetirizine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Meclizine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Pseudoephedrine; Triprolidine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Pyrilamine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Sedating H1-blockers: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.
Sincalide: (Moderate) Sincalide-induced gallbladder ejection fraction may be affected by concurrent medications, including H1-blockers. False study results are possible; thorough patient history is important in the interpretation of procedure results.
Triprolidine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as other H1-blockers.

Alavert/Allergy Relief/Claritin RediTab/Clear-Atadine/Dimetapp Children's Non-Drowsy Allergy/Loratadine Oral Tab Orally Dis: 5mg, 10mg
Alavert/Allergy Relief/Claritin/Clear-Atadine/Dimetapp Children's Non-Drowsy Allergy/Loratadine Oral Sol: 5mg, 5mL
Allergy Relief/Claritin/Claritin-D 24 Hour/Clear-Atadine/Loratadine/QlearQuil All Day & All Night Allergy Relief/Tavist ND Oral Tab: 10mg
Claritin Chewable/Loratadine Oral Tab Chew: 5mg, 10mg
Claritin Liqui-Gel/Loratadine/Quality Choice Allergy Relief Non-Drowsy Oral Cap: 10mg

NOTE: Do not exceed recommended dosage limits for the specific product prescribed; the following are general guidelines:

10 mg/day PO.

10 mg/day PO.

10 mg/day PO.

6 to 12 years: 10 mg/day PO.
2 to 5 years: 5 mg/day PO.
1 year: Safety and efficacy have not been established.

Loratadine is highly selective for histamine H1-receptors. Unlike cromolyn and nedocromil which block histamine release, H1-antagonists compete with free histamine for binding at H1-receptor sites. This competitive antagonism blocks the effects of histamine on H1-receptors in the GI tract, uterus, large blood vessels, and bronchial muscle. Loratadine does not readily cross the blood-brain barrier, and it preferentially binds at H1-receptors in the periphery rather than within the brain, which probably accounts for some of its nonsedating character. H1-blockers are similar in structure to anticholinergics, local anesthetics, antispasmodics, and ganglionic- and adrenergic-blocking agents, sharing some of their properties. H1-blockers possess anticholinergic properties in varying degrees; however, loratadine does not exert significant anticholinergic effects at therapeutic concentrations. In vitro studies have shown that loratadine has a weak affinity for acetylcholine and alpha-adrenergic receptors.

Loratadine is administered orally. It is 97% protein-bound and is excreted into breast milk. Loratadine has a high first pass effect and is almost completely metabolized in the liver to the minimally active metabolite, descarboethoxyloratadine. In vitro studies indicate that metabolism to descarboethoxyloratadine predominantly by CYP3A4 and, to a lesser extent, by cytochrome CYP2D6. In the presence of a CYP3A4 inhibitor, loratadine is metabolized to descarboethoxyloratadine predominantly by CYP2D6. The normal mean elimination half-lives of loratadine and its metabolite are 8.4 hours (range 3 to 20 hours) and 28 hours, respectively. Elimination occurs through the fecal and renal routes.
 
Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: CYP3A4, CYP2D6, P-gp
Metabolism of loratadine occurs predominantly by CYP3A4 and, to a lesser extent, by cytochrome CYP2D6. Concurrent administration with either ketoconazole, erythromycin (both CYP3A4 inhibitors), or cimetidine (CYP2D6 and CYP3A4 inhibitor) to healthy volunteers was associated with increased plasma concentrations of loratadine. However, in drug-drug interaction studies there were no clinically relevant changes in the safety profile of loratadine associated with these increases. Loratadine is also a substrate for P-glycoprotein (P-gp) transport; however, no clinically significant drug-drug interactions have been reported with P-gp inhibitors.

After oral administration, the onset of action of loratadine occurs within 1 to 3 hours, with peak effects in 8 to 12 hours and a duration of action greater than 24 hours. Administration with food increases absorption and AUC up to 40% for the syrup or tablets and up to 48% for the rapidly-disintegrating tablets. The time to peak concentrations (Tmax) is delayed by administration with food. However, since the clinical response is unaffected, the drug can be administered without regard to meals.

Loratadine is available over-the-counter without a prescription. Animal studies have not demonstrated a risk to the fetus but there are no adequate studies in pregnant women. Use during pregnancy only when the benefits of therapy outweigh the risks. Self-medication with loratadine during pregnancy is not recommended. Pregnant patients should see their health care professional for a proper diagnosis and for treatment recommendations. The American College of Obstetricians and Gynecologists (ACOG) and the American College of Allergy, Asthma, and Immunology consider loratadine an acceptable alternative in pregnancy, preferably after the first trimester, when first generation antihistamines are not tolerated.

Loratadine and its metabolite, desloratadine, are excreted into breast milk; breast-feeding women are advised to consult a healthcare professional prior to using loratadine. In one study, a single loratadine dose of 40 mg (4 times the usual dose) was administered to 6 lactating women. Average loratadine peak milk concentrations, 2 hours after administration, were 29.2 mcg/L (range 20.4 to 39 mcg/L); average desloratadine peak milk concentrations, 5.3 hours after loratadine administration, were 16 mcg/L (range 9 to 29.6 mcg/L). The total amount excreted in milk over 48 hours was 11.7 mcg of loratadine and desloratadine. The calculated average and maximum expected exposures of loratadine and desloratadine in milk were 0.46% and 1.1% of the maternal weight-adjusted dose, respectively, after the 40 mg dose. Approximately 3 mcg would be expected to be excreted in the milk with a 10 mg dose. Because of its lack of sedation and low milk concentrations, maternal use would not be expected to cause adverse effects in breast-fed babies and loratadine is considered usually compatible with breast-feeding. The British Society for Allergy and Clinical Immunology also recommends loratadine at the lowest dose as a preferred antihistamine in breast-feeding women. Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.