Trimethoprim

By Medically reviewed by hellodoktor

Generic Name: Trimethoprim Brand Name(s): Generics only. No brands available. Avability: Rx Pregnancy Category: C

Uses

What is Trimethoprim used for?

Trimethoprim is an antibiotic used to treat bacterial infections. It works by stopping the growth of bacteria.

How should I take Trimethoprim?

Take this medication by mouth on an empty stomach at least 1 hour before or 2 hours after a meal as directed by your doctor. It may be taken with food if stomach upset occurs. Dosage is based on your medical condition and response to therapy.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

Continue to take this medication until the full prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria to continue to grow, which may result in a relapse of the infection.

Inform your doctor if your condition persists or worsens after several days.

How do I store Trimethoprim?

Trimethoprim is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Trimethoprim in the bathroom or the freezer. There may be different brands of Trimethoprim that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Trimethoprim down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Trimethoprim?

Before taking trimethoprim, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, 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: a certain type of anemia (due to folate deficiency), kidney disease, liver disease, vitamin deficiency (folate or folic acid), blood disorders (such as bone marrow suppression, G6PD deficiency), mineral imbalances (such as high level of potassium or low level of sodium in the blood).

This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.

If you have diabetes, this product may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of low blood sugar (see Side Effects section). Your doctor may need to adjust your diabetes medication, exercise program, or diet.

Trimethoprim may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.

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

Older adults may be more sensitive to the side effects of this drug, especially mineral imbalance (high potassium blood level) and allergic reactions.

This medication is not recommended for use during pregnancy. It may harm an unborn baby. Consult your doctor for more details. This medication may lower your folic acid levels, increasing the risk of spinal cord defects. Therefore, check with your doctor to make sure you are taking enough folic acid.

Trimethoprim passes into breast milk. While there have been no reports of harm to nursing infants, consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Trimethoprim during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Trimethoprim. Trimethoprim is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Trimethoprim?

Diarrhea, nausea, vomiting, stomach upset, loss of appetite, changes in taste, and headache may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: signs of infection (such as fever, persistent sore throat), easy bruising/bleeding, unusual paleness, mental/mood changes, tiredness with fast/pounding/irregular heartbeat, dark urine, persistent nausea/vomiting, stomach/abdominal pain, yellowing eyes/skin, stiff neck, persistent headache, muscle weakness, extreme drowsiness, signs of low blood sugar (such as sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, or tingling hands/feet).

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.

Do not use anti-diarrhea products or narcotic pain medications if you have any of these symptoms because these products may make them worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

Get medical help right away if you have any very serious side effects, including: seizures.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Trimethoprim?

This drug should not be used with the following medication because a very serious interaction may occur: dofetilide.

If you are currently using this medication listed above, tell your doctor or pharmacist before starting trimethoprim.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: digoxin, methotrexate.

Although most antibiotics are unlikely to affect hormonal birth control such as pills, patch, or ring, a few antibiotics (such as rifampin, rifabutin) can decrease their effectiveness. This could result in pregnancy. If you use hormonal birth control, ask your doctor or pharmacist for more details.

This medication may interfere with certain laboratory tests (including kidney function and methotrexate blood levels), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

Trimethoprim may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Trimethoprim?

Trimethoprim may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Trimethoprim?

Trimethoprim may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Trimethoprim.

What is the dose of Trimethoprim for an adult?

Usual Adult Dose for Urinary Tract Infection

Recommended dose:

100 mg orally every 12 hours for 10 days or 200 mg orally every 24 hours for 10 days

Comments:

-Cultures and susceptibility tests should be performed to determine the susceptibility of the bacteria to this drug.

-Therapy may be initiated prior to obtaining the results of susceptibility tests.

Use: For the treatment of initial episodes of uncomplicated urinary tract infections due to susceptible strains of the following organisms: Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Enterobacter species, and coagulase-negative Staphylococcus species, including S. saprophyticus

Renal Dose Adjustments

Severe renal dysfunction (CrCl 15 to lea than 30 mL/min): Usual dose should be reduced by 50%

End-stage renal disease (CrCl less than 15 mL/min): Use is not recommended

Dialysis

Peritoneal dialysis is not effective and hemodialysis only moderately effective in eliminating this drug.

Other Comments

Administration advice:

-This drug may be taken with food to minimize the possibility of GI disturbance.

-To ensure maximal urinary concentrations it may be advantageous to take the dose before bedtime.

General:

-To reduce the development of drug-resistant bacteria and maintain the effectiveness of this drug and other antibacterial drugs, it should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.

-Cultures and susceptibility tests should be performed to determine the susceptibility of the bacteria to this drug. Therapy may be initiated prior to obtaining the results of these tests.

Patient advice:

-Patients should be counseled that antibacterial drugs should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold).

-Patients should be counseled to take the medication exactly as directed. Skipping doses or not completing the full course of therapy may decrease the effectiveness of the immediate treatment and increase the likelihood that bacteria will develop resistance.

What is the dose of Trimethoprim for a child?

Usual Pediatric Dose for Urinary Tract Infection

12 TO 18 YEARS OF AGE:

Recommended dose:

100 mg orally every 12 hours for 10 days or 200 mg orally every 24 hours for 10 days

Comments:

-Cultures and susceptibility tests should be performed to determine the susceptibility of the bacteria to this drug.

-Therapy may be initiated prior to obtaining the results of susceptibility tests.

Use: For the treatment of initial episodes of uncomplicated urinary tract infections due to susceptible strains of the following organisms: Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, Enterobacter species, and coagulase-negative Staphylococcus species, including S. saprophyticus

Usual Pediatric Dose for Otitis Media

Acute infections:

6 months or older: 5 mg/kg orally every 12 hours for 10 days

Use: For the treatment of acute otitis media due to susceptible strains of Streptococcus pneumoniae and Haemophilus influenzae

Precautions

-Safety and effectiveness in pediatric patients below the age of 2 months have not been established.

-Safety and effectiveness of this drug as a single agent has not been established in pediatric patients under 12 years of age.

-Safety and effectiveness for the treatment of acute otitis media has not been established in patients below the age of 6 months.

How is Trimethoprim available?

Trimethoprim is available in the following dosage forms and strengths:

  • Oral tablet,
  • Oral solution,
  • Compounding powder.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Trimethoprim, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: November 7, 2018 | Last Modified: September 12, 2019

You might also like