Trimethoprim UTI Tablets

What is Trimethoprim?

Trimethoprim is an antibiotic, taken as a tablet by mouth. It works by stopping certain bacteria from multiplying, preventing them from spreading further and helping to clear the infection. The medication contains 200 mg of the active ingredient trimethoprim and belongs to a group of medicines called antibacterials. As the name suggests, these treatments are effective against a wide range of bacteria.

What is Trimethoprim Used For?

The most common use of trimethoprim is to treat bacterial infections such as UTIs, particularly cystitis in women. In some cases, it can also be prescribed for conditions such as acne or chest infections, though this is at the doctor's discretion. Prescription Doctor only offers trimethoprim as an antibiotic to treat cystitis.

Understanding Cystitis Before Treatment with Trimethoprim

Cystitis is a bacterial infection affecting the urinary tract. It is commonly referred to as a urinary tract infection (UTI) or water infection.

Risk Factors for Women

Women are at a higher risk of developing UTIs compared to men. This is due to anatomical differences, such as the shorter distance between the urethra and anus, as well as the length of the urethra itself in women.

How Cystitis Occurs

Cystitis is typically caused by bacteria, most commonly E. coli, entering the urethra and ascending into the bladder, leading to inflammation.

Sexual Activity and Cystitis

Although not classified as a sexually transmitted infection (STI), UTIs often occur following sexual intercourse. To minimise the risk, it's advisable to urinate as soon as possible after sex to flush out any bacteria that may have entered the urethra.

Other Causes of Cystitis

• Urinary Tract Obstructions: Such as bladder and kidney stones.
• Pregnancy: Pressure on the bladder can increase the risk of urinary tract infections.
• Foreign Bodies: Such as catheters, can also cause infection.
• Conditions like diabetes and multiple sclerosis can increase the likelihood of developing a UTI.

While less common, men can also develop cystitis. If symptoms are present, it's crucial to consult a GP to determine the underlying cause.

How Does Trimethoprim Work?

Trimethoprim works by blocking the production of tetrahydrofolic (folic) acid, a key compound bacteria need to survive. This means the bacteria are unable to replicate and spread further, effectively cutting off the infection at its source. Because of its effects on the body, the medication is sometimes associated with low blood folic acid levels.

Trimethoprim can target infections this way because of a key difference between bacterial cells and human body cells. Bacterial cells need to produce their own folic acid to grow and multiply, while human cells get theirs from food. This difference means the medication can act on the infection without significantly affecting the body's own cells, which is why it's suitable to use as an antibiotic.

How Long Does it Take for Trimethoprim to Work?

You should start to feel better within a few days of taking trimethoprim UTI tablets, with some users reporting relief from symptoms, such as pain and discomfort, after just 24 hours. Even if you notice a significant improvement early on in your treatment, it’s essential to complete the entire course of antibiotics to prevent the infection from returning.

How Effective is Trimethoprim for UTI?

Clinical studies have found that a three-day course of trimethoprim antibiotics can achieve a bacterial eradication rate of more than 90% in uncomplicated cystitis, with a low risk of adverse effects. In general practice, the expected cure rate of the medication is between 85% and 90%.

When it comes to bacterial resistance, one trial found that trimethoprim was ineffective against 29.8% of E. coli and Klebsiella cases (common causes of UTIs). This is in line with wider surveillance data across England, which has found similarly high resistance rates, between 28% and 33%. If you do find that the medication isn’t working for you, there are alternative treatments available.

How to Take Trimethoprim Tablets

Trimethoprim must be swallowed whole with a glass of water, so be sure not to chew or break the tablets. It can be taken with or without food. It’s essential that you always take trimethoprim tablets exactly as prescribed by your doctor.

Trimethoprim Dose for UTI

The most common dose of trimethoprim for UTIs is one 200 mg tablet twice daily for 3-7 days. More complicated or severe infections can take up to 14 days to clear. If you are prescribed trimethoprim for recurrent cystitis, the usual dose is 100 mg once a day, usually at night. You can also use Trimethoprim tablets following the onset of an identifiable trigger, in which case the dosage would be one single 200 mg tablet.

Should you decide to take trimethoprim tablets as a preventive measure, you may be advised to keep going with the treatment for up to six months.

What if You Forget to Take Trimethoprim

If you forget to take a trimethoprim dose, you should do so as soon as you remember, unless it’s almost time for the next one. In this scenario, simply skip the first one and proceed with the second as normal. Never try to take two at the same time. Should you find that you’re regularly missing trimethoprim doses, you could try setting a reminder on your phone or calendar.

What If You Take Too Much Trimethoprim

If you take too much trimethoprim, contact your doctor immediately or visit your nearest A&E department. Do not drive yourself; ask someone else to take you or call for an ambulance. Take the medicine packaging or leaflet with you so the doctors know exactly what you've taken.

Trimethoprim Side Effects and Cautions

While trimethoprim is a safe and common treatment, it is essential to have a clear understanding of what to expect before starting your course. This section outlines potential side effects, important cautions, and when to seek medical advice to ensure you use the medication safely and effectively.

Trimethoprim 200mg Side Effects

Like most medications, trimethoprim can cause side effects, though not everyone will experience them. Even so, it’s recommended that you have a clear understanding of what to expect before you start treatment.

Potential Trimethoprim side effects include:

Please note that this is not an exhaustive list of trimethoprim side effects. More information can be found within the Patient Information Leaflet supplied with your medication. If you are struggling to manage adverse reactions, consult your clinician, who may recommend an alternative treatment.

If you experience any side effects, whether listed above or in the patient information leaflet, inform your doctor or consult a pharmacist. You can also report them via the MHRA’s Yellow Card Scheme.

When to Stop Taking Trimethoprim

Stop taking trimethoprim and get medical help straight away if you notice any of the following:

• Swelling of the face, lips, tongue or throat, difficulty breathing, or collapse
• Reddish patches on the skin with blistering, skin peeling, or ulcers in the mouth, throat, nose, genitals or eyes, sometimes coming on with fever or flu-like symptoms
• A widespread rash, high temperature and swollen lymph nodes
• A headache, fever, stiff neck, tiredness, feeling generally unwell, and eyes becoming very sensitive to bright light

These are all signs of rare but serious reactions, and need urgent attention rather than waiting to see if they pass. For anything less urgent, speak to your doctor or pharmacist before stopping your course early.

Interactions and Warnings for Trimethoprim Antibiotics

Trimethoprim isn't suitable for everyone, and it can interact with certain other medicines. Below, we've covered who should avoid trimethoprim, what to tell your doctor before starting treatment, and which medicines to be cautious of.

Who Can Take Trimethoprim for UTIs?

Trimethoprim tablets can be prescribed to most adults, though the medication is not suitable for everyone. For example, you should not take the medication if you:

• Have had an allergic reaction to trimethoprim
• Deal with anaemia
• Suffer from severe liver problems
• Have ever developed a severe skin rash or skin peeling, blistering and/or mouth sores after taking trimethoprim
• Are within the first 3 months of pregnancy or might be pregnant

If any of the above applies to you, or you’re unsure about which treatment is most appropriate, it’s important to consult a doctor.

Trimethoprim Precautions

Tell your clinician or doctor if any of the following apply to you before starting treatment:

• You have kidney disease (or if you are having dialysis treatment)
• You have a deficiency of folic acid (may cause anaemia)
• You are pregnant
• You have fructose intolerance or an intolerance to some sugars
• You suffer from porphyria

Trimethoprim antibiotics can increase blood potassium levels (hyperkalaemia). People at risk of this condition include those with poorly controlled diabetes, kidney problems, or those on certain medications or potassium supplements. Signs of hyperkalaemia include muscle cramps, irregular heart rhythm, nausea, dizziness, headaches, or diarrhoea.

Trimethoprim Allergic Reaction

Do not take Trimethoprim if you are allergic to trimethoprim or any of its ingredients listed in the Patient Information Leaflet. This treatment contains lactose. Please contact your doctor before using this medicine if you have a known lactose intolerance.

If you experience signs and symptoms of an allergic reaction, stop taking the medicine and consult your doctor as soon as possible. Seek emergency medical attention if necessary.

Signs of an allergic reaction include:

• Difficulty breathing
• Hives
• Skin rash
• Swelling of the face, lips, tongue and throat

Trimethoprim 200mg Tablets and Other Medicines

Some medications can interact with trimethoprim or increase the risk of side effects. So inform your clinician if you take:

• Warfarin or Acenocoumarol
• Phenytoin
• Rifampicin
• Repaglinide
• Digoxin
• Methotrexate
• Heparin
• Potassium supplements
• Procainamide
• Pyrimethamine and dapsone

You can find more details about potential interactions between Trimethoprim and other medications in the Patient Information Leaflet.

It’s not possible to say whether trimethoprim is compatible with herbal remedies or other complementary medicines, since these treatments are not tested in the same way as pharmaceutical drugs. You should always tell your doctor if you are taking any other medications before starting trimethoprim.

Frequently Asked Questions About Trimethoprim 200mg