Patient leaflet - Isoniazid 50 mg tablets

1. What Isoniazid tablets are and what they are used for

Isoniazid belongs to a group of medicines called antibacterials. Isoniazid works by killing bacteria that cause tuberculosis (also known as TB).

Isoniazid is used to treat tuberculosis inside the lungs (pulmonary TB) and outside the lungs (extrapulmonary TB). Tuberculosis is a serious infectious disease that can be passed on to other people. If left untreated it can spread through your body and may be fatal. It is important that you receive eﬀective treatment for this condition.

2. What you need to know before you take Isoniazid tablets

Do not take Isoniazid tablets

if you are allergic to Isoniazid or any of the other ingredients of this medicine (listed in section 6)
if you have ever had serious liver problems after taking any medicine
if you have ever developed a severe skin rash or skin peeling, blistering and/or mouth sores after taking isoniazid.

Warnings and precautions

Serious skin reactions such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS) and acute generalised exanthematous pustulosis (AGEP) have been reported in association with isoniazid treatment. Stop using isoniazid and seek medical attention immediately if you notice any of the symptoms described in section 4.

Talk to your doctor or pharmacist before taking Isoniazid tablets:

if you have epilepsy or have ever had convulsions (ﬁts)
if you have diabetes
if you drink a lot of alcohol regularly
if you have, or have had, problems with your liver or kidneys
if you suﬀer or have suﬀered from psychosis (mental disturbances with hallucinations or delusions)
if you are malnourished (severely underfed)
if you have HIV infection
if you have extra-pulmonary TB (outside the lungs)

Other medicines and Isoniazid tablets

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines, including:

Stavudine (used for the treatment of HIV)
Any medicine for the treatment of epilepsy such as carbamazepine, phenytoin or primidone
Disulﬁram (for the treatment of alcoholism)
Rifampicin, para-aminosalicylic acid or any other drug used to treat TB
The benzodiazepine diazepam (for the treatment of anxiety)
Levodopa (for the treatment of Parkinson's disease)
Itraconazole or ketoconazole (for the treatment of fungal infections)
Any other medicine, including medicines obtained without a prescription.

These medicines can interfere with how well your treatment works.

Taking Isoniazid tablets with food and drink

Isoniazid should be taken on an empty stomach, so take it at least 30 minutes before a meal or two hours after a meal. This helps your body absorb isoniazid more easily.

Avoid drinking alcohol with isoniazid. This may damage your liver.

Isoniazid may interact with foods containing histamine or tyramine (e.g. matured cheeses, cured meat, some ﬁsh like tuna, salmon and mackerel, wine and beer), causing symptoms including headache, sweating, ﬂushing, fast, uneven or forceful heartbeat (palpitations), dizziness, feel lightheaded or faint (due to low blood pressure). These foods should be avoided if you are receiving isoniazid.

Your doctor will be able to advise further.

Pregnancy and breast-feeding

If you are pregnant, trying to become pregnant or breast-feeding, ask your doctor or pharmacist for advice before taking Isoniazid tablets.

Isoniazid tablets contain hydrogenated castor oil

This medicine contains hydrogenated castor oil which may cause stomach upset and diarrhoea.

3. How to take isoniazid tablets

Always take Isoniazid exactly as your doctor has told you.

Important: Your doctor will choose the dose that is right for you. Your dose will be shown clearly on the label that your pharmacist puts on your medicine. If it does not, or you are not sure, ask your doctor or pharmacist.

Remember: Isoniazid tablets should not be taken with food. You should swallow Isoniazid tablets whole with a glass of water.

Adults

The usual dose of Isoniazid is 4 to 5 mg per kilogram (kg) of your bodyweight per day, up to a maximum of 300 mg daily. This may be taken as a single dose or as divided doses throughout the day. Your doctor will tell you exactly how much medicine to take and when to take it. Higher doses (up to 10 mg per kg per day) may be used to treat tuberculous meningitis (tuberculosis causing inﬂammation of the brain's membranes).

Elderly

If you are elderly, your doctor may tell you to take a slightly lower dose because your liver and kidneys are not working as well as they should.

Use in children

The usual dose for children above the age of three months is 10 to 15 mg per kg of bodyweight per day. This may be taken by your child as a single dose or as divided doses throughout the day.

Your doctor will tell you exactly how much medicine your child should take and when to take it. Children under three months should not take Isoniazid.

Medical check-ups

While you are taking this medicine, your doctor may ask you to have check-ups and blood tests.

These are to:

check that your liver is working properly
make sure your medicine is working properly
check the dose you are taking is right for you.

If you take more Isoniazid tablets than you should

Do not take more Isoniazid tablets than you should. If you accidentally take too much, immediately contact your nearest hospital emergency department or your doctor.

Taking too much Isoniazid may cause dizziness or feeling as though the room is spinning around, feeling and being sick, ﬁts and acidosis (upset of the acid balance in the body). These eﬀects may require emergency treatment in hospital.

If you forget to take Isoniazid tablets

Do not take a double dose to make up for a forgotten dose. Simply take the next dose as planned.

If you stop taking Isoniazid tablets

Do not stop taking Isoniazid tablets without ﬁrst talking to your doctor. It is important you take the full course of this medicine, as directed by your doctor, in order to clear the infection that causes tuberculosis.

If you stop taking this medicine suddenly you may get withdrawal symptoms including a headache, diﬃculty in sleeping, having more dreams, feeling irritable and feeling nervous.

If you have any further questions about the use of this medicine, ask your doctor or pharmacist.

4. Possible side eﬀects

Like all medicines, this medicine can cause side eﬀects, although not everybody gets them.

If you experience any of the following side eﬀects contact your doctor as soon as possible:

Inﬂammation of the pancreas, which causes severe pain in the abdomen and back (pancreatitis, frequency not known).
A red, scaly widespread rash with bumps under the skin and blisters accompanied by fever. The symptoms usually appear at the initiation of treatment (acute generalised exanthematous pustulosis, frequency not known).
Lupus-like syndrome, causing symptoms such as swollen joints, tiredness and rashes (frequency not known).
Severe extensive skin damage (separation of the epidermis and superﬁcial mucous membranes) (toxic epidermal necrolysis, (TEN), may aﬀect up to 1 in 1,000 people).
A drug reaction that causes rash, fever, inﬂammation of internal organs, haematologic abnormalities and systemic illness (DRESS syndrome, may aﬀect up to 1 in 1,000 people).
Yellowing of the skin or whites of the eyes, or urine getting darker and stools paler, fatigue, weakness, malaise, loss of appetite, nausea or vomiting caused by liver problems (hepatitis, may aﬀect up to 1 in 100 people).

Other side eﬀects:

Convulsions (ﬁts)
Severe stomach pain
Connective tissue disorders such as Lupus syndrome which can aﬀect the skin and kidneys (symptoms may include a butterﬂy-shaped rash over the cheeks and nose, tiredness, a high temperature, feeling or being sick, joint pain and weight loss)
Mental disturbances including psychotic reactions such as hallucinations and delusions
Blood disorders which may make you more likely to get infections
High blood sugar levels, although you may not notice any symptoms
Inﬂammation of blood vessels (vasculitis) – (frequency not known)
Acidosis (upset of the acid balance in the body) which may make you feel or be sick, be drowsy or have breath that smells of “pear drops”
Gynaecomastia (increased size of breasts in men)
Low levels of vitamin B6 and nutrition problems. This can make you feel irritable, have diﬃculty sleeping, weak muscles, cracks at the corner of the mouth or lose weight
Eye problems such as visual disturbances and eye pain
If you have severe problems with your kidneys, you may get loss of hearing and ringing in your ears
Tingling or numbness in the hands or feet (pins and needles)
Constipation
Diﬃculty in starting to pass urine
Upset stomach and diarrhoea
Fever
Feeling and being sick
Loss of appetite and chills
Dry mouth
Overactive reﬂexes
Dizziness or feeling if the room is spinning around (vertigo)
Red or itchy skin rash or peeling of the skin.

Side eﬀects with this medicine are more common in people aged over 35 and in people who break down Isoniazid more slowly. The risk of having side eﬀects increases with high doses of Isoniazid tablets.

Reporting of side eﬀects

If you get any side eﬀects, talk to your doctor or pharmacist. This includes any possible side eﬀects not listed in this leaﬂet. You can also report side eﬀects directly via Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side eﬀects you can help provide more information on the safety of this medicine

5. How to store Isoniazid

Keep out of the reach and sight of children.

Do not use Isoniazid tablets after the expiry date on the pack. The expiry date refers to the last day of that month.

This product does not require any special temperature storage conditions.

Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.

6. Contents of the pack and other information

What Isoniazid tablets contains

The active substance in Isoniazid tablets is isoniazid. Isoniazid tablets come in two strengths: 50 mg and 100 mg. Each 50mg tablet contains 50 mg of isoniazid. Each 100mg tablet contains 100 mg of isoniazid.

The other ingredients in Isoniazid tablets are microcrystalline cellulose (E460), maize starch, starch pregelatinised partially, crospovidone (E1202), colloidal silicon dioxide (E551), talc (E553b), hydrogenated castor oil, puriﬁed water.

What Isoniazid looks like and contents of the pack

Isoniazid 50 mg Tablets are white to oﬀ white, round (approx. 6.30 mm), biconvex tablets embossed with 50 on one side and plain on the other side.

Isoniazid 100 mg Tablets are white to oﬀ white, round (approx. 8.00 mm), biconvex tablets embossed with 100 on one side and plain on the other side.

Isoniazid 50 mg Tablets are available in blister packs of 28 tablets, 56 tablets and 100 tablets.

Isoniazid 100 mg tablets are available in blister packs of 28 tablets, 56 tablets and 100 tablets.

Not all pack sizes may be marketed.

Marketing Authorisation Holder

DAWA Limited

5 Sandridge Close,

Harrow, Middlesex,

HA1 1XD, UK

Manufacturer

Drugsrus Limited