Polymyxin b and trimethoprim (Ophthalmic)
Medically reviewed by Drugs.com. Last updated on Jun 8, 2022.
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Antibiotic Combination
Pharmacologic Class: Trimethoprim
Uses for polymyxin b and trimethoprim
Polymyxin B and trimethoprim combination is used to treat eye infections, including acute bacterial conjunctivitis and blepharoconjunctivitis.
Polymyxin B and trimethoprim belong to the class of medicines known as antibiotics. They work by killing the bacteria or preventing their growth.
Polymyxin b and trimethoprim is available only with your doctor's prescription.
Before using polymyxin b and trimethoprim
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For polymyxin b and trimethoprim, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to polymyxin b and trimethoprim or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of polymyxin B and trimethoprim combination in children younger than 2 months of age. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of polymyxin B and trimethoprim combination in the elderly.
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking polymyxin b and trimethoprim, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using polymyxin b and trimethoprim with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using polymyxin b and trimethoprim with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Arsenic Trioxide
- Azilsartan Medoxomil
- Candesartan Cilexetil
- Chloral Hydrate
- Cholera Vaccine, Live
- Olmesartan Medoxomil
Using polymyxin b and trimethoprim with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using polymyxin b and trimethoprim with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use polymyxin b and trimethoprim, or give you special instructions about the use of food, alcohol, or tobacco.
Proper use of polymyxin b and trimethoprim
Use polymyxin b and trimethoprim only as directed by your doctor. Do not use more of it, do not use it more often, and do not use it for a longer time than your doctor ordered. To do so may increase the chance of too much medicine being absorbed into the body and the chance of side effects.
To use the eye drops (solution):
- Shake the medicine well just before each use.
- Wash your hands with soap and water before and after you use polymyxin b and trimethoprim.
- Tilt the head back. Press your finger gently on the skin just beneath the lower eyelid and 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. Do not blink. Keep the eyes closed and apply pressure to the inner corner of the eye with your finger for 1 or 2 minutes to allow the medicine to be absorbed by the eye.
- 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 medicines.
To help clear up your infection completely, keep using polymyxin b and trimethoprim for the full treatment time even if you feel better after the first few doses. The infection may not clear up if you stop using the medicine too soon. Do not miss any doses.
Do not use polymyxin b and trimethoprim while wearing contact lenses. Wait at least 15 minutes after you use the medicine before putting the contact lenses back in.
The dose of polymyxin b and trimethoprim will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of polymyxin b and trimethoprim. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For eye infections:
- For ophthalmic dosage form (eye drops):
- Adults and children 2 months of age and older—Use one drop in the affected eye(s) every 3 hours for 7 to 10 days. Your doctor may tell you to use the drops more often during severe infections.
- Children younger than 2 months of age—Use and dose must be determined by your doctor.
- For ophthalmic dosage form (eye drops):
If you miss a dose of polymyxin b and trimethoprim, take 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.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions while using polymyxin b and trimethoprim
It is very important that your eye doctor (ophthalmologist) check your progress at regular visits to make sure polymyxin b and trimethoprim is working properly and to check for unwanted effects.
If itching, redness, swelling, or other signs of eye or eyelid irritation occur, check with your doctor right away. This may mean that you are allergic to polymyxin b and trimethoprim.
If your symptoms do not improve within a few days or if they become worse, check with your eye doctor (ophthalmologist) right away.
Check with your doctor right away if you have an eye injury, eye infection, or plan to have eye surgery.
Polymyxin b and trimethoprim side effects
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:
- Increased redness, burning, stinging, or itching of the eye
Incidence not known
- Blurred vision
- change in color vision
- difficulty seeing at night
- increased sensitivity of the eyes to sunlight
- increased tearing
- rash around the eye
- swelling of the eyelid
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.
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- Drug class: ophthalmic anti-infectives
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