Cotri 80mg/400mg Tablet

Cotri contains trimethoprim 80mg + sulfamethoxazole 400mg, the combination known as co-trimoxazole. Made by Unexo Laboratories. Pack of 200 tablets. Prescription only.

Uses

The two drugs block two steps in the same bacterial folate pathway, so together they kill bacteria that either one alone would only slow down. Prescribed for:

• Urinary tract infections: cystitis and some kidney infections.
• Chest infections: acute bronchitis flare-ups.
• Middle ear infection (otitis media) in children.
• Traveller’s diarrhoea and shigella dysentery.
• Typhoid where the bacteria are still sensitive, now uncommon in Pakistan.
• Pneumocystis pneumonia (PCP): treatment and prevention in HIV, transplant, and chemotherapy patients.
• Toxoplasmosis prevention in immunocompromised patients.
• Skin infections including MRSA boils.
• Nocardia and some rarer infections.

Resistance to co-trimoxazole is high in Pakistan for E. coli and typhoid, so a culture report is worth having before relying on it for a UTI.

Dosage

Follow the prescription. Standard adult ranges:

• UTI, bronchitis, ear infection: 2 tablets every 12 hours, 5 to 14 days.
• Traveller’s diarrhoea, shigella: 2 tablets every 12 hours, 5 days.
• PCP treatment: based on body weight, roughly 4 to 5 tablets every 6 to 8 hours, 14 to 21 days.
• PCP prevention: 2 tablets once daily or three times a week.
• Kidney patients: half dose if creatinine clearance is 15 to 30, avoid below 15.
• Children over 6 weeks: dose by weight, usually as the suspension.

Two of these tablets equal one DS (double strength) tablet.

How To Take

• Swallow with a full glass of water, with or without food. Food reduces stomach upset.
• Drink plenty of fluids through the course, sulfamethoxazole can crystallise in the kidneys if urine is concentrated.
• Keep doses 12 hours apart.
• Missed dose: take it when remembered unless the next one is close, never double up.
• Finish the full course.
• Stay out of strong sun or use sunscreen, the drug makes skin burn faster.

Side Effects

Common:

• Nausea, vomiting, loss of appetite.
• Diarrhoea.
• Skin rash, itching.
• Sore or inflamed tongue.
• Headache.
• Thrush after longer courses.

Stop and get medical help for:

• Rash that spreads fast, blisters, peels, or affects mouth, eyes, or genitals (Stevens-Johnson syndrome, more common with this drug than most antibiotics).
• Fever with sore throat, mouth ulcers, unusual bruising or bleeding (bone marrow suppression).
• Yellow skin or eyes, dark urine.
• Muscle weakness, irregular heartbeat, tingling (high potassium).
• Severe watery diarrhoea.
• Swelling of face or throat, trouble breathing.
• Confusion, stiff neck, severe headache (aseptic meningitis, rare).

Precautions

• Sulfa allergy: do not take. This covers reactions to any sulfonamide including some diuretics (frusemide, thiazides) and sulfasalazine, ask the doctor if unsure.
• G6PD deficiency: can cause red cell breakdown, common enough in Pakistan to be worth checking if there is family history or past jaundice with medicines.
• Folate deficiency, anaemia: trimethoprim worsens it, folinic acid may be added.
• Kidney or liver disease: dose adjustment or avoidance.
• Elderly: higher risk of severe skin reactions, high potassium, and marrow suppression, especially on long courses.
• HIV patients: side effects are much more frequent.
• Pregnancy: avoid in the first trimester (folate effect) and last month (newborn jaundice risk). Only on a doctor’s decision.
• Breastfeeding: avoid with premature or jaundiced infants, otherwise short courses are generally accepted.

Contraindications

• Sulfonamide or trimethoprim allergy.
• Severe liver damage.
• Severe kidney failure where blood levels cannot be monitored.
• Severe blood disorders.
• Infants under 6 weeks.
• Combined with dofetilide.

Interactions

• Warfarin: INR rises sharply, needs monitoring.
• Methotrexate: dangerous rise in levels, avoid together.
• ACE inhibitors, ARBs, spironolactone, potassium supplements: high potassium.
• Phenytoin: levels rise.
• Sulfonylureas (glibenclamide, gliclazide): low blood sugar.
• Digoxin: levels rise in the elderly.
• Ciclosporin: kidney damage.
• Pyrimethamine: megaloblastic anaemia.
• Oral typhoid vaccine: keep 3 days apart.
• Lab tests: can raise creatinine readings without true kidney damage.

Storage

Keep in the original container below 30°C, away from moisture and light. Out of reach of children. Do not use after expiry.

Information only, not a replacement for medical advice.