Tinidazole

Fasigyn (tinidazole) is a nitroimidazole antimicrobial used to treat certain protozoal infections and bacterial vaginosis. In the UK, tinidazole is used for trichomoniasis, giardiasis, amoebiasis and bacterial vaginosis, in line with local prescribing guidance.

What is Fasigyn used for?

Tinidazole should only be used for infections that are proven, or strongly suspected, to be caused by susceptible organisms. It does not work against viruses such as colds or flu, so do not use it for viral infections.

If you are unsure why a specialist has prescribed these tablets, do not hesitate to ask. Also, keep in mind that in the United Kingdom, this medicine is only available on prescription.

Trichomoniasis (sexually transmitted infection)

Tinidazole is used to treat trichomoniasis caused by Trichomonas vaginalis. Because trichomoniasis is a sexually transmitted infection, sexual partners should be treated with the same dose at the same time to help prevent re-infection.

Bacterial vaginosis (BV)

Tinidazole is used to treat bacterial vaginosis in non-pregnant adult women.

Infections caused by organisms called protozoa

Tinidazole is used for giardiasis caused by Giardia duodenalis, and for intestinal amoebiasis and amoebic liver abscess caused by Entamoeba histolytica (in adults and in children aged 3 and over).

Infection associated with stomach ulcers in combination with other drugs

Tinidazole may be used off-label as part of some Helicobacter pylori eradication regimens in combination with other medicines. Only use it for this purpose if it has been prescribed by a clinician.

In all of these uses, the active ingredient is tinidazole, so you may often see this name when looking for information about Fasigyn tablets.

How to take Fasigyn tablets

Take tinidazole with food to help reduce stomach upset. Swallow the tablets with water (about 100 mL). If you have trouble swallowing, ask your pharmacist or doctor for advice. Tablets may only be crushed and mixed with syrup if a healthcare professional has told you to do this.

Here are some dos and don'ts when taking Fasigyn.

Dos:

• If you become pregnant during the course, tell your doctor as soon as possible;
• If you get white patches in your mouth or on your tongue during treatment, or soon after finishing the course, contact your doctor or pharmacist;
• If you get itching or burning around your genitals and/or white discharge during treatment, or soon after finishing the tablets, tell your doctor. Tinidazole may contribute to yeast overgrowth;
• If you are about to start taking other medicines during the course, check with your doctor first;
• Tell any healthcare professional treating you that you are taking tinidazole.

Don'ts

• Do not give your tablets to anyone else, even if they have similar symptoms or the same condition;
• Do not try to get prescription medicines without a prescription to treat any condition.

If you miss a dose:

• Take it as soon as you remember, unless it is nearly time for your next dose;
• Do not take more than prescribed to make up for a missed dose.

If you overdose:

• For emergencies, call 999, or contact your doctor and/or NHS 111.

Side effects of Fasigyn

If you feel unwell during the course, even if your symptoms are not listed here, check with your doctor. Some reactions can vary from person to person.

The most common side effects reported with a single 2 g dose include a metallic or bitter taste, nausea, weakness, tiredness or generally feeling unwell, stomach upset (dyspepsia, cramps or upper abdominal discomfort), vomiting, loss of appetite, headache, dizziness and constipation.

Skin rash or itching

If you develop a severe rash, swelling, trouble breathing, or other signs of a serious allergic reaction, stop taking the medicine and get medical help straight away.

Fasigyn dose

Follow your doctor's instructions exactly. The dose depends on the condition being treated.

• Trichomoniasis (adults): 2 g by mouth as a single dose with food. Treat sexual partners with the same dose at the same time.
• Giardiasis: Adults: 2 g by mouth as a single dose with food. Children (aged 3 and over): 50 mg/kg as a single dose (max 2 g) with food.
• Amoebiasis (intestinal): Adults: 2 g/day for 3 days with food. Children (aged 3 and over): 50 mg/kg/day (max 2 g/day) for 3 days with food.
• Amoebic liver abscess: Adults: 2 g/day for 3-5 days with food. Children (aged 3 and over): 50 mg/kg/day (max 2 g/day) for 3-5 days with food.
• Bacterial vaginosis (non-pregnant adult women): 2 g once daily for 2 days with food, or 1 g once daily for 5 days with food.

Contraindications and precautions

Do not take tinidazole if you have had a hypersensitivity or allergic reaction to tinidazole or other nitroimidazole derivatives.

• Pregnancy: Do not use tinidazole during the first trimester of pregnancy. If you are pregnant, especially in the 2nd or 3rd trimester, or planning a pregnancy, discuss the risks and benefits with your doctor.
• Breast-feeding: Breastfeeding should be interrupted during treatment with tinidazole and for 3 days after the last dose.

Stop taking tinidazole and contact a clinician promptly if you develop abnormal neurological signs such as numbness, tingling or seizures.

Interaction with other medicines and other forms of interaction

Tell your doctor about all medicines and supplements you take.

Alcohol

Avoid alcoholic drinks and products containing ethanol or propylene glycol during treatment with tinidazole and for 3 days after the last dose, because a disulfiram-like reaction may occur. This can cause flushing, abdominal cramps, nausea, vomiting and headache. Do not take tinidazole if you have taken disulfiram within the last 2 weeks.

Do not take medicines containing alcohol either, such as some cough syrups.

Anticoagulants

Tinidazole may increase the effect of warfarin and other coumarin anticoagulants, which can prolong prothrombin time/INR. The anticoagulant dose may need to be adjusted during treatment with tinidazole and for up to 8 days after stopping it.

Effects on ability to drive and use machines

Tinidazole may cause dizziness or other neurological side effects in some people. If you feel dizzy or unwell, avoid driving or using machinery.

How to store Fasigyn tablets

• Store at controlled room temperature 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).
• Protect from light and keep in the original packaging.
• Keep out of the reach of children and pets.

Do not dispose of the medicine by flushing it down the toilet. Ask a pharmacist how to dispose of it properly.