In the U.S.—

• Mast cell stabilizer, ophthalmic
• Antiallergic, ophthalmic

Pemirolast ( pe-MEER-oh-last) is used to treat the itching in your eyes that happens with allergies.

Pemirolast works by preventing certain types of inflammatory cells from releasing irritating substances that cause allergic symptoms.

This medicine is available only with your doctor's prescription, in the following dosage forms:

Topical
• Ophthalmic solution (U.S.)

In deciding to use a medicine, the risks of using the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For pemirolast, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to pemirolast. Also tell your doctor and pharmacist if you are allergic to any other substances, such as [foods, preservatives, or dyes].

Pregnancy—Pemirolast has not been shown to cause birth defects or other problems in humans. However, in rats given 20,000 to 30,000 times the human dose of pemirolast, there was an increase in the number of fetal bone and heart deformities as well as an increased number of fetal implantation losses.

Breast-feeding—It is not known whether pemirolast passes into human breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast feeding. Mothers who are taking this medicine and who wish to breast-feed should discuss this with their doctor.

Children—This medicine has been tested in children 3 years of age and older and, in effective doses, has not been shown to cause different side effects or problems than it does in adults.

Older adults—There is no specific information available comparing the use of pemirolast in the elderly with use in other age groups.

• Contact lens–related irritation—Pemirolast should not be used to treat this condition

Pemirolast is used to help treat the itching that often occurs with allergic conjunctivitis.

• To use the eye drops form of this medicine:
  • First, wash your hands. Then tilt the head back and, pressing your finger gently on the skin just beneath the lower eyelid, pull the lower eyelid away from the eye to make a space. Drop the medicine into this space. Let go of the eyelid and gently close the eyes. Blink a few times to make sure the eye is covered with the medicine.
  • To keep the medicine as germ-free as possible, do not touch the applicator tip to any surface (including the eye). Also, keep the container tightly closed. Serious damage to the eye and possible loss of vision may result from using contaminated eye drops.

Dosing—

Use this medicine only as directed. Do not use more of it and do not use it more often than your doctor ordered.

Follow your doctor's orders or the directions on the label. The following information includes only the average dose of ophthalmic pemirolast. If your dose is different, do not change it unless your doctor tells you to do so.

• For ophthalmic dosage form (eye drops):
  • For eye allergies:
    • Adults and children 3 years of age and older—Use one to two drops in each affected eye four times a day.
    • Children up to 3 years of age—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, apply it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Keep the medicine from freezing. Do not refrigerate.
• Do not keep outdated medicine or medicine no longer needed. Ask your health care professional how you should dispose of any medicine you do not use. Be sure that any discarded medicine is out of the reach of children.

You should avoid wearing contact lenses when your eyes are red and irritated from your allergies.

For patients who continue to wear contact lenses and whose eyes are not red, be certain to wait at least 10 minutes after applying pemirolast to your eyes before replacing any contact lenses normally worn.

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 as soon as possible if any of the following side effects occur:

• Less common
  • Cough (mucus-producing);  headache (severe) ;  stomach pain and cramping;  pain and tenderness around eyes and cheekbones;  painful menstrual bleeding;  runny or stuffy nose ;  tightness in chest;  troubled breathing 
  
  

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome.

• More common
  • Chills;  cough;  fever;  sneezing;  sore throat  
  
  

• Less common
  • Back pain;  burning feeling in eye;  eyelid swelling;  eye dryness;  foreign body feeling in eye;  general feeling of eye discomfort;  increased itching of the eye;  redness of the eye 
  
  

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