Skip to main content
Clemastine

Clemastine Side Effects

Robert Chad Hakim, PharmD, BCCCPAllison Gourley, PharmD
Reviewed by Robert Chad Hakim, PharmD, BCCCP, Allison Gourley, PharmD
Last reviewed on May 17, 2024

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

  • Sleepiness
  • Dizziness
  • Loss of coordination
  • Stomach upset

Less Common Side Effects

  • Fatigue
  • Dry mouth, nose, or throat
  • Headache
  • Confusion
  • Blurry vision

Source: DailyMed

The following Clemastine side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common or rare

Less common or rare with azatadine, cetirizine, clemastine, cyproheptadine, desloratadine, dexchlorpheniramine, diphenhydramine, or loratadine

Abdominal or stomach pain

burning

chills

clay-colored stools or dark urine

cough

diarrhea

difficulty swallowing

dizziness

fast or irregular heartbeat

fever

headache

hives

itching

prickly sensations

puffiness or swelling of the eyelids or around the eyes, face, lips or tongue

redness of skin

seizures

shortness of breath

skin rash

swelling

tightness in chest

tingling

unusual tiredness or weakness

wheezing

Check with your doctor as soon as possible if any of the following side effects occur:

Less common or rare

Sore throat

unusual bleeding or bruising

unusual tiredness or weakness

Symptoms of overdose

Clumsiness or unsteadiness

convulsions (seizures)

drowsiness (severe)

dryness of mouth, nose, or throat (severe)

feeling faint

flushing or redness of face

hallucinations (seeing, hearing, or feeling things that are not there)

shortness of breath or troubled breathing

trouble in sleeping

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Drowsiness

dry mouth, nose, or throat

gastrointestinal upset, stomach pain, or nausea

headache

increased appetite and weight gain

thickening of mucus

Less common or rare

Acid or sour stomach

belching

blurred vision or any change in vision

body aches or pain

clumsiness or unsteadiness

confusion (not with diphenhydramine)

congestion

constipation

cough

diarrhea

difficult or painful urination

difficulty in moving

difficult or painful menstruation

dizziness (not with brompheniramine or hydroxyzine)

drowsiness (with high doses of desloratadine and loratadine)

dryness of mouth, nose, or throat

early menstruation

fast heartbeat

fever

heartburn

hoarseness

increased sensitivity of skin to sun

increased sweating

indigestion

loss of appetite

joint pain

muscle aching or cramping

muscle pains or stiffness

nausea

nightmares (not with azatadine, chlorpheniramine, cyproheptadine, desloratadine, hydroxyzine, or loratadine)

ringing or buzzing in ears

runny nose

skin rash

swollen joints

stomach discomfort, upset or pain

tender swollen glands in neck

tremor

unusual excitement, nervousness, restlessness, or irritability

vomiting

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

why trust our exports reliability shield

Why trust our experts?

Robert Chad Hakim, PharmD, BCCCP, started his full-time career as a clinical pharmacist at UCLA Health in the general medicine, general cardiology, and ICU units after completing residency in 2016. He also was the preceptor for the general medicine rotation from 2017 to 2021, which was a required rotation for all pharmacy residents.
Allison Gourley, PharmD, is a kidney and pancreas transplant pharmacist at a teaching hospital in the San Francisco Bay Area. When she’s not educating patients about their immunosuppressants, she's actively involved in transplant research.

Was this page helpful?