POM-V Prescription Required

Triquest 333 mg/ml + 67 mg/ml Oral Suspension for Horses

Active ingredients: Sulfadiazine, Trimethoprim

Form

Liquid

Species

Horses

Manufacturer

Alfasan Nederland B.V.

VMD MA No.

36408/5029

What it's used for

For the treatment of infections in horses caused by micro-organisms susceptible to the combination of trimethoprim and sulfadiazine, such as infections of...

Full indications, dosage and side effects ↓

View official SPC (PDF)

The prescription itself has a price. See what practices near you charge for a consultation and the written prescription fee.

Paying less for Sulfadiazine + Trimethoprim

1

Ask your vet for a written prescription

They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.
2

Fill it at a registered online retailer

The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

Your prescription rights → VMD register of retailers →

Prescription required

Your vet must provide a written prescription on request. You can then purchase from any licensed online retailer.

Clinical information

Triquest 333 mg/ml + 67 mg/ml Oral Suspension for Horses — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 26 Mar 2026.

For the treatment of infections in horses caused by micro-organisms
susceptible to the combination of trimethoprim and sulfadiazine, such as
infections of the upper respiratory tract, the urogenital system and wound
infections.

Do not use in cases of hypersensitivity to the active substances or to any of the
excipients.
Do not use in animals with severe kidney or liver damage.

Issued: August 2024
AN: 03112/2022

Horses:
Common
(1 to 10 animals / 100 animals
treated):
Digestive tract disorder (e.g. loose stool, diarrhoea,
colitis).
Undetermined
(frequency cannot be
estimated from the available
data)
Hypersensitivity reactions such as urticaria.
Inappetence.
Hepatic or renal disorders.
Hematologic effects, such as anaemia,
thrombocytopenia, or leukopenia.
Haematuria, crystalluria, tubular
obstruction.
Reporting adverse events is important. It allows continuous safety monitoring of
a veterinary medicinal product. Reports should be sent, preferably via a
veterinarian, to either the marketing authorisation holder or its local
representative or the national competent authority via the national reporting
system. See also section 16 of the package leaflet for respective contact
details.

The use of the veterinary medicinal product in horses under 1 year old should be
avoided.
Cross-resistance has been shown between sulfadiazine and other sulfonamides. Use
of the product should be carefully considered when susceptibility testing has shown
resistance to sulfonamides because its effectiveness may be reduced
In case of infections involving purulent conditions, trimethoprim-sulfonamides
combinations are not recommended due to a diminished efficacy under such
conditions.

Special precautions for use in animals
Caution should be exercised when treating new-born animals and animals with
liver damage.
Renal impairment leads to risk of accumulation, increasing the risk of side
effects in long term treatment.
Throughout the treatment, animals should have free access to drinking water to
avoid possible crystalluria.
Use the veterinary medicinal product cautiously in horses with blood
dyscrasias.
Use of the veterinary medicinal product should be based on identification and
susceptibility testing of the target pathogen(s). If this is not possible, therapy
should be based on epidemiological information and knowledge of susceptibility
of the target pathogens at farm level, or at local/regional level.
Use of the veterinary medicinal product should be in accordance with official,
national and regional antimicrobial policies.
Special precautions to be take by the person administering the veterinary
medicinal product to animals
This product contains sulfadiazine, a sulfonamide which can cause
hypersensitivity (allergic) reactions following skin contact or accidental
ingestion. Hypersensitivity to sulfonamides may lead to cross reactions with
other antibiotics. Allergic reactions to sulfonamides may occasionally be
serious.
If symptoms develop following exposure, such as a skin rash or difficulty with
breathing, seek medical advice immediately and show the package leaflet or
the label to the physician.
This product may cause gastrointestinal disturbances, or irritation of the skin
and eyes, after exposure. Wearing impervious gloves is recommended when
administering the product. In the case of contact with skin, wash with soap and
water. In the case of contact with the eyes, rinse thoroughly with water.
Special precautions for the protection of the environment:
Not applicable

Issued: August 2024
AN: 03112/2022
Other precautions
Not applicable.

Potentiated sulfonamides can cause fatal arrhythmias in horses sedated with alpha2-
adrenoceptor agonists.

This veterinary medicinal product does not require any special storage
conditions.

Meat and offal: 6 months
Milk: Not authorised for use in mares producing milk for human consumption
5.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.