What Should I Tell My Healthcare Provider?You should talk with your healthcare provider prior to taking timolol if you have:
- Heart failure
- A slow heart rate (bradycardia)
- Liver disease, such as liver failure, cirrhosis, or hepatitis
- Kidney disease, such as kidney failure (renal failure)
- A history of stroke or transient ischemic attack (TIA)
- Heart block
- Sick sinus syndrome
- Chronic obstructive pulmonary disease (COPD)
- An upcoming surgery
- Myasthenia gravis
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant (see Timolol and Pregnancy)
- Breastfeeding (see Timolol and Breastfeeding).
Make sure to tell your healthcare provider about any other medicines you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.
(Click Precautions and Warnings With Timolol to learn more, including information on who should not take the drug.)
How Does It Work?Timolol belongs to a group of drugs called beta-adrenergic blocking agents, more often known as beta blockers. As the name implies, these medications block beta receptors in the body. Beta receptors are located in a number of places, including the eyes, heart, and blood vessels. Stress hormones such as adrenaline bind to these receptors and cause certain reactions in the body, such as:
- Increased heart rate
- Increased force with which the heart pumps blood
- Higher blood pressure (both systolic and diastolic blood pressure)
- Constricted blood vessels
- Increased eye pressure.
By blocking beta receptors, timolol causes the reverse effect of stress hormones. It decreases heart rate and both systolic and diastolic blood pressure. It is not entirely clear how the medication works to prevent migraines or to improve survival after a heart attack.
Timolol lowers the pressure in the eye by decreasing the amount of fluid produced by the eye (known as aqueous humor).