Drug Interactions With Timolol
More Information on Interactions With Timolol
The following sections explain in detail the potentially negative interactions that can occur when Timolol is combined with any of the drugs listed above.
Calcium Channel Blockers
Combining timolol with certain calcium channel blockers may cause dangerously low blood pressure or a dangerously slow heart rate (bradycardia). You may need to be monitored closely if you take these medications together. In some cases, timolol and a calcium channel blocker should not be combined.
Stopping clonidine without stopping timolol could increase the risk of dangerously high blood pressure, strokes, and other serious problems. This is more common with oral beta blockers, such as timolol tablets, but could happen with timolol eyedrops as well. If you need to stop taking clonidine but are still taking timolol, ask your healthcare provider for further instructions.
CYP 2D6 Inhibitors
Timolol is metabolized by a specific liver enzyme known as CYP 2D6. Some medications (known as CYP 2D6 inhibitors) slow down the activity of this enzyme, causing an increase in the level of timolol in the blood. This could lead to serious side effects. Different medications inhibit the enzyme to different extents; some interactions may be minor, while others may be quite severe. Check with your healthcare provider before combining timolol with a CYP 2D6 inhibitor.
Taking timolol with digoxin may cause a dangerously slow heart rate (bradycardia). You may need to be monitored closely if you take these medications together. In some cases, timolol and digoxin should not be combined.
Timolol may decrease the effectiveness of injectable epinephrine for treating allergic reactions. If you have a serious allergy that may require treatment with epinephrine, timolol might not be a good choice for you.