Trimethoprim — Drug Interactions, Alcohol & Pregnancy Guide

Last reviewed: · Source: US FDA drug label database

About Trimethoprim

Trimethoprim is a common antibiotic for uncomplicated UTIs, especially in women. It should be avoided in pregnancy (folate antagonist) and in those with folate deficiency or blood disorders.

Also sold as: Monotrim

Drug class Antibiotic (dihydrofolate reductase inhibitor)
Used for UTIs, Lower respiratory tract infections
Max adult dose 200mg twice daily for 7 days for UTI
OTC in UK Prescription only

Trimethoprim and Alcohol

🟡 USE WITH CAUTION

Avoid alcohol with trimethoprim — it impairs your immune system while you are fighting a UTI and may worsen nausea.

Full guide →

Trimethoprim in Pregnancy

🔴 AVOID

Avoid trimethoprim in the first trimester — it blocks folic acid, which the baby's neural tube needs; nitrofurantoin is the usual UTI alternative.

Full guide →

⭐ Recommended on Amazon

⭐ Top Pick · Recommended on Amazon

Weekly Pill Organiser

Keep track of multiple medications with a clear 7-day pill box — reduces missed and double doses.

View on Amazon →
Recommended on Amazon

Medication Record Book

Log your medications, doses and times to stay safe and flag any concerns to your pharmacist.

View on Amazon →
Recommended on Amazon

Lockable Medicine Cabinet

Store all your medications safely in one place, out of reach of children.

View on Amazon →

Affiliate links below. As an Amazon Associate we earn from qualifying purchases at no extra cost to you.

👨‍⚕️

Not sure if Trimethoprim is safe with your other medications?

Speak to a pharmacist online →