Cystitis Medicines: What to Take?
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Treat Cystitis Online →Nitrofurantoin for Cystitis
Nitrofurantoin is a common antibiotic used to treat urinary tract infections (UTIs) including cystitis. It is the NICE first-line recommendation for uncomplicated cystitis in women, provided kidney function is adequate (eGFR ≥45 ml/min).
It works by stopping harmful bacteria from multiplying — specifically by interfering with bacterial energy metabolism and DNA synthesis. Crucially, nitrofurantoin is rapidly excreted from the bloodstream into the urine, concentrating at the site of infection in the bladder. This makes it highly effective for urinary tract infections but means it is not useful for infections elsewhere in the body.
- NICE first-line for uncomplicated UTI/cystitis
- Usually taken for 5–7 days (100mg modified-release twice daily with food, or 50mg four times daily)
- Take with food or immediately after eating to reduce stomach upset
- May turn urine dark yellow or brown — normal, temporary, nothing to worry about
- Also sold as Macrobid and Macrodantin
- Does not contain penicillin — safe for those with penicillin allergy
Who cannot take nitrofurantoin?
- Those with known allergy to nitrofurantoin
- Those with severe kidney disease or poor kidney function (eGFR <45 ml/min)
- Those with porphyria or G6PD deficiency
- Those with diabetes-related kidney complications
- Those with anaemia or vitamin B deficiency
Trimethoprim for Cystitis
Trimethoprim is an antibiotic used to treat urinary tract infections, cystitis, and occasionally chest infections and acne. It was historically the first-choice UTI antibiotic in the UK, but increasing antibiotic resistance has meant that nitrofurantoin has become the preferred first-line option. NICE now recommends trimethoprim as the alternative where nitrofurantoin is not appropriate, and where local resistance rates are low.
That said, trimethoprim remains effective for the vast majority of UTI cases — approximately 90% of infections. It is usually taken twice daily.
- NICE second-line for UTI/cystitis (alternative to nitrofurantoin)
- Standard dose: 200mg twice daily for 7 days
- Does not contain penicillin — safe for penicillin-allergic patients
- Suitable for both adults and children (dose adjusted by weight/age)
- Avoid in early pregnancy — interferes with folate metabolism
Who cannot take trimethoprim?
- Those allergic to trimethoprim
- Those with liver or kidney problems
- Those with anaemia or low folic acid
- Those with porphyria or blood disorders
- Pregnant women (especially first trimester) — discuss with your GP
Antibiotic resistance reminder: Continuing trimethoprim until your full course is finished — even if you feel better early — is vital. Stopping midway significantly increases the risk of the infection returning and of developing antibiotic resistance.
Can You Take Trimethoprim and Nitrofurantoin Together?
While both antibiotics can technically be taken together, it is very unlikely your prescriber would recommend both simultaneously. Nitrofurantoin is given first. In the rare case that your infection proves resistant to nitrofurantoin, trimethoprim or a different, typically stronger antibiotic will be prescribed.
See our full comparison guide: Nitrofurantoin vs Trimethoprim: which is better for UTIs?
Over-the-Counter Options
There are no over-the-counter antibiotics for cystitis — nitrofurantoin and trimethoprim are prescription-only medicines in the UK. However, several OTC products can help manage symptoms while you await or obtain antibiotics:
- Paracetamol or ibuprofen — for pain and discomfort relief
- Urinary alkalinising sachets (e.g. Cystopurin, sodium citrate products) — may help relieve burning by reducing urine acidity, though evidence is limited
- Cranberry products — some evidence for prevention, limited evidence for treatment of active infections
OTC products provide symptomatic relief only. If symptoms persist beyond 24 hours or are severe, prescription antibiotic treatment is needed.
How to Get Cystitis Treatment
If symptoms of cystitis have persisted for more than 24 hours, seek medical advice. Although antibiotics are prescription-only and cannot be bought over the counter, you do not need to book a GP appointment. Access Doctor is a GPhC-registered online pharmacy — complete a short consultation reviewed by our GPhC-registered pharmacist independent prescribers. Once approved, your antibiotic is delivered straight to your door, usually next working day.
💊 NICE First-Line Antibiotic
Nitrofurantoin (Macrobid)
MHRA-approved first-line antibiotic for cystitis & UTIs. Prescription via GPhC-regulated online consultation.
Order Nitrofurantoin →💊 Prescription Antibiotic
Trimethoprim
MHRA-approved alternative antibiotic for cystitis. Suitable where nitrofurantoin is not appropriate.
Order Trimethoprim →Order Cystitis Antibiotics Online
Our GPhC-registered pharmacist independent prescribers review your consultation and prescribe nitrofurantoin or trimethoprim — with next-day discreet delivery.
Treat Cystitis Online →Frequently Asked Questions About Cystitis Medicines
What is nitrofurantoin used for in cystitis?
Nitrofurantoin is the NICE first-line antibiotic for uncomplicated UTIs and cystitis. It concentrates in the urine at the site of infection, making it highly effective for bladder infections. It must be taken with food to reduce stomach upset.
Does nitrofurantoin contain penicillin?
No — nitrofurantoin is not part of the penicillin family and can be safely prescribed to patients with penicillin allergy.
How long does nitrofurantoin take to work on a UTI?
Most people notice symptom improvement within a few days. Always complete the full prescribed course even if you feel better, to prevent the infection returning and antibiotic resistance developing.
What is trimethoprim and when is it used?
Trimethoprim is NICE second-line for UTIs — recommended as an alternative to nitrofurantoin where appropriate. It is effective in around 90% of cases. Avoid in early pregnancy. It does not contain penicillin.
Can I buy cystitis antibiotics over the counter?
No — nitrofurantoin and trimethoprim are prescription-only. However, you can obtain a prescription via Access Doctor’s GPhC-regulated online consultation — no GP appointment needed, with next-day delivery.
Can I take trimethoprim and nitrofurantoin at the same time?
It is very unlikely a prescriber would recommend both simultaneously. Nitrofurantoin is prescribed first; if the infection is resistant, trimethoprim or a stronger antibiotic is then prescribed separately.
References
- NICE. Urinary tract infection (lower) — women. Clinical Knowledge Summaries. Available at: cks.nice.org.uk/topics/urinary-tract-infection-lower-women
- NHS. Cystitis. Available at: nhs.uk/conditions/cystitis
- UKHSA. English surveillance programme for antimicrobial utilisation and resistance (ESPAUR). Available at: gov.uk
- Electronic Medicines Compendium. Nitrofurantoin 100mg m/r capsules — SmPC. Available at: medicines.org.uk/emc
- Electronic Medicines Compendium. Trimethoprim 200mg tablets — SmPC. Available at: medicines.org.uk/emc
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. Nitrofurantoin and trimethoprim are prescription-only medicines — a medical consultation is required before they can be dispensed. If you have a fever, loin/back pain, or are pregnant, seek urgent in-person medical care. In an emergency, call 999.