Before using timolol, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as preservatives like benzalkonium chloride), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: lung disease (such as current or past history of asthma, severe chronic obstructive pulmonary disease), certain types of irregular heartbeats (such as sinus bradycardia, second or third degree AV block), certain types of heart disease (such as severe heart failure, cardiogenic shock), kidney disease, liver disease, diabetes, low blood flow to the brain (cerebrovascular insufficiency), overactive thyroid disease, muscle weakness disorders, severe allergies.

If you develop an eye infection or injury, or have eye surgery, check with your doctor about whether you should continue to use your current bottle of timolol. You may be advised to start using a new bottle.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This product may prevent the fast/pounding heartbeat you would usually feel when your blood sugar level falls too low (hypoglycemia). The risk is higher if you have diabetes, or are vomiting, fasting, or not eating regularly. Other symptoms of low blood sugar level, such as dizziness and sweating, are not affected by this drug.

If you have diabetes, this product may make it harder to control your blood sugar levels. Check your blood sugar levels regularly as directed by your doctor. Tell your doctor right away if you have symptoms of high blood sugar such as increased thirst/urination. Your doctor may need to adjust your diabetes medication, exercise program, or diet.

After you apply this drug, your vision may become temporarily blurred. Do not drive, use machinery, or do anything that needs clear vision until you can do it safely.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breastfeeding.