loratadine

Loratadine is a second-generation antihistamine drug used to relieve nasal and non-nasal symptoms of hay fever (seasonal allergic rhinitis) and to treat chronic itching from hives (chronic idiopathic urticaria).

Antihistamines work by blocking the activity of histamine, a natural chemical irritant in the body that causes allergy symptoms. Loratadine is available over the counter (OTC) in the U.S.

Histamine is a chemical released by mast cells and basophils, types of immune cells, in response to allergen exposure. Histamine binds to histamine H1 receptors, protein molecules located on cell membranes, and activates the immune response that results in inflammation and allergy symptoms. Loratadine binds to histamine H1 receptors, preventing their activation by histamine and the resultant allergic reactions.

Like other second-generation antihistamines, loratadine selectively binds to histamine H1 receptors primarily located on respiratory smooth muscle cells, cells lining blood vessel walls, the gastrointestinal tract, and immune cells. Loratadine does not cross the blood-brain barrier and has no central nervous system (CNS) effects, hence, it does not cause drowsiness, sedation, and impairment of psychomotor functions like first-generation antihistamines do.

Loratadine is approved for use in adults and pediatric patients of age 2 years and older, for the relief of nasal and non-nasal symptoms from:

• Seasonal and perennial allergic rhinitis (nasal inflammation)
• Chronic idiopathic urticaria (hives)

• Do not use loratadine if you are hypersensitive to any of the components in the formulation.
• Do not administer OTC cough medicines containing loratadine to children below 2 years of age and use with caution in children over 2 years.
• Use with caution in elderly patients.
• Use with caution in patients with impaired kidney or liver function.
• Loratadine may potentiate the sedative effect of sedative drugs and alcohol if taken concurrently.
• Some formulations contain benzyl alcohol which has been associated with a potentially fatal “gasping syndrome” in newborns. Use with caution.
• Some formulations may contain phenylalanine, an amino acid. Take with caution if you have phenylketonuria, an inherited disorder with inability to metabolize phenylalanine.

Common side effects of loratadine include:

• Headache
• Drowsiness (somnolence)
• Fatigue
• Dry mouth (xerostomia)
• Oral inflammation (stomatitis)
• Abdominal pain
• Altered salivation
• Taste perversion (dysgeusia)
• Loss of appetite (anorexia)
• Gas (flatulence)
• Indigestion (dyspepsia)
• Constipation
• Diarrhea
• Loose stools
• Gastritis
• Hiccups
• Increase in appetite
• Nausea
• Vomiting
• Chest pain
• High or low blood pressure (hypertension or hypotension)
• Palpitations
• Rapid heart rate (tachycardia)
• Supraventricular tachycardia
• Flushing
• Fainting (syncope)
• Wheezing
• Upper respiratory tract infection
• Dry nose
• Nasal bleeding (epistaxis)
• Cough
• Coughing up blood (hemoptysis)
• Bronchial inflammation (bronchitis)
• Bronchospasm
• Shortness of breath (dyspnea)
• Inflammation of the voice box (laryngitis)
• Throat inflammation (pharyngitis)
• Flu-like symptoms
• Viral infections
• Feeling unwell (malaise)
• Rigors
• Fever
• Dizziness
• Vertigo
• Migraine
• Sleeplessness (Insomnia)
• Nightmares
• Loss of memory (amnesia)
• Nervousness
• Agitation
• Irritability
• Lack of concentration
• Confusion
• Anxiety
• Depression
• Reduced skin sensation (hypoesthesia)
• Numbness and tingling (paresthesia)
• High muscle tone (hypertonia)
• Tremor
• Muscle spasm (hyperkinesia)
• Muscle pain (myalgia)
• Weakness (asthenia)
• Lower limb pain
• Back pain
• Joint pain (arthralgia)
• Voice disorder (dysphonia)
• Eye pain
• Blurred vision
• Eyelid twitching (blepharospasm)
• Inflammation of conjunctiva, the membrane over the eye whites and inner eyelid surfaces (conjunctivitis)
• Ear pain (otalgia)
• Ringing in the ears (tinnitus)
• Dry hair
• Skin rash
• Dry skin (xeroderma)
• Itching (pruritus)
• Dermatitis
• Skin photosensitivity
• Excessive sweating (diaphoresis)
• Purple bruises due to bleeding beneath the skin (purpuric disease)
• Swelling beneath the skin and mucous membranes (angioedema)
• Changes in urination
• Urinary incontinence
• Urinary retention
• Urine discoloration
• Inflammation of the vagina (vaginitis)
• Painful menstruation (dysmenorrhea)
• Heavy menstrual bleeding
• Decreased libido
• Impotence
• Breast pain (mastalgia)
• Weight gain
• Increased thirst

Less common side effects of loratadine include:

• Swelling of extremities (peripheral edema)
• Abnormal liver function
• Liver inflammation (hepatitis)
• Jaundice
• Liver tissue death (hepatic necrosis)
• Low platelet count (thrombocytopenia)
• Severe allergic reaction (anaphylaxis)
• Seizure
• Overgrowth of breast tissue (breast hypertrophy)
• Hair loss (alopecia)
• Red skin lesions from drug reaction (erythema multiforme)

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

• Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
• Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
• Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
• Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

Syrup

• 5 mg/5 mL

Tablet

• 10 mg

Tablet, Chewable

• 5 mg

Tablet, Disintegrating

• 5 mg
• 10 mg

Capsule

• 10 mg

Adult:

Allergic Rhinitis

• 10 mg orally once daily or 5 mg twice daily; not to exceed 10 mg/day

Urticaria

• 10 mg orally once daily; not to exceed 10 mg/day

Dosing Considerations

• Renal impairment (GFR below 30 mL/minute): 10 mg orally every other day
• Hepatic impairment: 10 mg orally every other day

Pediatric:

• Children below 2 years: Safety and efficacy not established

Allergic Rhinitis

• Children 2-6 years: 5 mg orally once daily
• Children above 6 years: 10 mg orally once daily; not to exceed 10 mg/day

Urticaria

Children above 6 years: 10 mg orally once daily

Dosing Modifications

Renal impairment (GFR below 30 mL/minute)

• Children 2-6 years: 5 mg orally every other day
• Children 6 years: 10 mg orally every other day

Hepatic impairment

• Children 2-6 years: 5 mg orally every other day
• Children 6 years: 10 mg orally every other day

Administration

Claritin RediTabs: Dissolve on the tongue

Overdose

• Loratadine overdose can cause drowsiness (somnolence), rapid heart rate (tachycardia), and headache in adults, and palpitations and drug-related movement disorders (extrapyramidal symptoms) in children.
• Overdose treatment is symptomatic and supportive care, which may include inducing vomiting or performing gastric lavage and administration of activated charcoal to eliminate any undigested drug and other measures as deemed necessary.

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

• Severe Interactions of Loratadine include:
  • mavacamten
• Serious Interactions of Loratadine include:
  • carbamazepine
  • cimetidine
  • clarithromycin
  • erdafitinib
  • erythromycin base
  • erythromycin ethylsuccinate
  • erythromycin lactobionate
  • erythromycin stearate
  • everolimus
  • isocarboxazid
  • lasmiditan
  • metoclopramide intranasal
  • olopatadine intranasal
  • rifabutin
  • rifampin
  • sotorasib
  • tepotinib
  • tranylcypromine
• Loratadine has moderate interactions with at least 133 different drugs.
• Loratadine has mild interactions with at least 53 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider about all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or healthcare provider if you have any questions about the medication.

• Animal reproductive studies show no fetal harm, however, there are no adequate and well-controlled studies on loratadine use in pregnant women. Use the lowest effective dose of loratadine during pregnancy, only if clearly needed.
• Loratadine is present in breast milk. Make a decision to discontinue nursing or loratadine, taking into account the importance of the drug to the mother. If a breastfeeding infant is exposed to loratadine in breast milk, monitor the baby for drowsiness, jitteriness, and irritability.
• Antihistamines may reduce milk production if administered before the establishment of lactation. 

• Take loratadine exactly as prescribed, or as per label instructions if self-medicating with OTC drug.
• Avoid concurrent use of alcohol and other sedative drugs with loratadine, it may potentiate their sedative effects.
• Although second-generation antihistamines are generally non-sedating, loratadine may cause drowsiness. Exercise caution and avoid driving and other hazardous activities until the drug’s effects can be determined.
• Store safely out of reach of children.
• In case of overdose, seek medical help or contact Poison Control.