Clemastine

Clemastine is an over-the-counter and prescription medication used to treat Allergic Rhinitis, Urticaria, and Angioedema. 

• Clemastine is available under the following different brand names:

Adult and pediatric dosage

Tablet

• 1.34mg
• 2.68mg

Syrup

• 0.67 mg/5mL

Allergic Rhinitis

Adult dosage

• 1.34 mg orally every 12 hours; not to exceed 8.04 mg/day for syrup or 2.68 mg/24 hours for tablets

Pediatric dosage

• Children younger than 6 years of age: 0.05 mg/kg/day as clemastine base or 0.335-0.67 mg/day clemastine fumarate (0.25-0.5 mg base/day) divided every 8-12 hours; not to exceed 1.34 mg (1 mg base)
• Children 6-12 years of age: 0.67-1.34 mg clemastine fumarate (0.5-1 mg base) every 12 hours; not to exceed 4.02 mg/day (3 mg/day base)
• Children 12 years or older: As in adults

Urticaria

Adult dosage

• 2.68 mg orally once daily-every 8 hours; not to exceed 8.04 mg/day

Pediatric dosage

• Children younger than 6 years of age: 0.05 mg/kg/day as clemastine base or 0.335-0.67 mg/day clemastine fumarate (0.25-0.5 mg base/day) divided every 8-12 hours; not to exceed 1.34 mg (1 mg base)
• Children 6-12 years of age: 0.67-1.34 mg clemastine fumarate (0.5-1 mg base) every 12 hours; not to exceed 4.02 mg/day (3 mg/day base)
• Children 12 years of older: As in adults

Angioedema

Adult dosage

• 2.68 mg orally once daily-every 8 hours; not to exceed 8.04 mg/day

Dosage Considerations – Should be Given as Follows: 

• See "Dosages."

Common side effects of Clemastine include:

• drowsiness, 
• dizziness, 
• headache, 
• constipation, 
• stomach upset, 
• blurred vision, 
• trouble walking or clumsiness, and
• dry mouth, nose, or throat

Serious side effects of Clemastine include:

• hives, 
• difficulty breathing, 
• swelling of the face, lips, tongue, or throat, 
• mental or mood changes, 
• hallucinations, 
• irritability, 
• nervousness, 
• confusion, 
• ringing in the ears, 
• trouble urinating, 
• easy bruising, 
• unusual bleeding, 
• fast or irregular heartbeats, 
• seizure, 
• rash, 
• itching, and
• severe dizziness

Rare side effects of Clemastine include:

• none 

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

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

• Clemastine has severe interactions with no other drugs.
• Clemastine has serious interactions with the following drugs:
  • calcium/magnesium/potassium/sodium oxybates
  • eluxadoline
  • isocarboxazid
  • lonafarnib
  • metoclopramide intranasal
  • pitolisant
  • sodium oxybate
  • tranylcypromine
• Clemastine has moderate interactions with at least 206 other drugs. 
• Clemastine has minor interactions with the following drugs:
  • ashwagandha
  • brimonidine
  • eucalyptus
  • nettle
  • ruxolitinib topical
  • sage
  • Siberian ginseng

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

Contraindications

• Documented hypersensitivity
• Lower respiratory disease, e.g., asthma (controversial)
• Preemies and neonates
• Nursing women

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Clemastine?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Clemastine?”

Cautions

• Caution in narrow angle glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, or bladder neck obstruction

Pregnancy and Lactation

• May be acceptable during pregnancy.
• Lactation: Enters breast milk, not recommended.