Isoniazid, Oral/Injection

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KEY POINTS

• This medicine is taken by mouth or given by injection to prevent or treat tuberculosis infections. Take it exactly as directed.
• Keep all appointments for tests to see how this medicine affects you.
• This medicine may cause unwanted side effects. Tell your healthcare provider if you have any side effects that are serious, continue, or get worse.
• Tell all healthcare providers who treat you about all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take.

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What are other names for this medicine?

Type of medicine: antituberculosis

Generic and brand names: isoniazid, oral; isoniazid, injection

What is this medicine used for?

This medicine is taken by mouth to treat tuberculosis infections. It is prescribed with other medicines. When used alone, there is a risk that you will develop resistance to the infection and this medicine will no longer be effective.

It may also be used to prevent TB for people at high risk of infection.

This medicine may also be given by injection (shot).

This medicine may be used to treat other conditions as determined by your healthcare provider.

What should my healthcare provider know before I take this medicine?

Before taking this medicine, tell your healthcare provider if you have ever had:

• An allergic reaction to any medicine
• Diabetes
• HIV infection
• Kidney or liver disease
• Problems with alcohol or drug abuse
• Nerve disease or tingling in hands or feet
• Seizures
• Side effects such as fever, chills, or arthritis from taking this medicine before

Your healthcare provider may want your vision checked before you start taking this medicine and while you are taking it.

Females of childbearing age: Tell your healthcare provider if you are pregnant or plan to become pregnant while taking this medicine. It is not known whether this medicine will harm an unborn baby. Do not breast-feed without your healthcare provider's approval.

How do I take it?

Check the label on the medicine for directions about your specific dose. Take this medicine exactly as your healthcare provider prescribes. Do not take more or less or take it longer than prescribed. Do not stop taking this medicine without your healthcare provider's approval. Keep taking it even if you feel better.

Do not use this medicine for any other infection unless your healthcare provider approves.

It is best to take this medicine on an empty stomach 1 hour before meals or 2 hours after meals. However, you may take this medicine with food if it upsets your stomach. A liquid form is available if you cannot swallow the tablets. If you have the liquid form of this medicine, the measuring spoon, cup, dropper, or oral syringe that comes with the medicine, or ask your pharmacist for one. Do not use a kitchen spoon because the dose may not be correct.

Injections of this medicine are usually given by a healthcare provider. These shots are normally given in the muscles of the thigh, upper arms, or buttocks. You may be taught how to give yourself these shots. Make sure you understand all instructions before giving yourself a shot.

Your healthcare provider may instruct you to take vitamin B-6 (pyridoxine) with this medicine to lessen its side effects.

What if I miss a dose?

If you miss a dose, take it as soon as you remember unless it is almost time for the next scheduled dose. In that case, skip the missed dose and take the next one as directed. Do not take double doses. If you are taking only one dose a day and you miss the dose one day, do not double the dose the next day. If you are not sure of what to do if you miss a dose, or if you miss more than one dose, contact your healthcare provider.

What if I overdose?

If you or anyone else has intentionally taken too much of this medicine, call 911 or go to the emergency room right away. If you pass out, have seizures, weakness or confusion, or have trouble breathing, call 911. If you think that you or anyone else may have taken too much of this medicine, call the poison control center. Do this even if there are no signs of discomfort or poisoning. The poison control center number is 800-222-1222.

Symptoms of an acute overdose may include: nausea, vomiting, dizziness, slurred speech, blurred vision, hallucinations, trouble breathing, seizures, coma.

What should I watch out for?

This medicine can cause liver problems or other serious adverse effects. You will need to have blood tests regularly to see how this medicine affects you. Keep all appointments for these tests. Contact your healthcare provider right away if you develop severe tiredness or weakness, nausea, vomiting, unexplained loss of appetite, dark urine, itching or rash, fever, severe stomach pain, constant numbness or tingling in hands or feet, or yellowing of your eyes and skin.

Your healthcare provider will want to see you regularly while you are taking this medicine. You may need to have blood tests regularly to see how this medicine affects you. Keep all appointments for these tests.

Daily use of alcohol while you are taking this medicine may cause liver problems. Do not drink alcohol while you are taking this medicine.

This medicine may cause eye problems or make you dizzy. Tell your healthcare provider right away if you develop blurred vision or if you have any change in your vision with or without eye pain. Do not drive or operate machinery unless you are fully alert and can see clearly.

If you need emergency care, surgery, lab tests, or dental work, tell the healthcare provider or dentist you are taking this medicine.

If you have diabetes: This medicine may affect your blood sugar level and change the amount of insulin or other diabetes medicines you may need. Check your blood glucose more often while taking this medicine. Talk to your healthcare provider about this.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your healthcare provider if you have any side effects that continue or get worse.

Life-threatening (Report these to your healthcare provider right away. If you cannot reach your healthcare provider right away, get emergency medical care or call 911 for help.): Allergic reaction (hives; itching; rash; trouble breathing; tightness in your chest; swelling of your lips, tongue, and throat).

Serious (Report these to your healthcare provider right away.): Severe weakness or tiredness; unexplained loss of appetite; severe nausea, vomiting, or stomach pain; vision changes; yellowing of your skin or eyes; dark urine; light-colored bowel movements; tingling or burning of hands or feet; unusual bruising or bleeding; fever; itching or rash; confusion or abnormal behavior; memory problems; seizures; severe drowsiness; severe joint or muscle pain; swollen glands.

Other: Dizziness, nausea, diarrhea, swollen or painful breasts.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your healthcare provider if you are taking:

• Acetaminophen and medicines that contain acetaminophen
• Antacids that contain aluminum, such as Gaviscon, Maalox, and Mylanta (Take antacids at least 2 hours before or 2 hours after you take this medicine.)
• Antianxiety medicines such as alprazolam (Xanax), diazepam (Valium), estazolam (ProSom), midazolam (Versed), and triazolam (Halcion)
• Antidepressants such as amitriptyline, citalopram (Celexa), desipramine (Norpramin), duloxetine (Cymbalta), escitalopram (Lexapro), fluvoxamine (Luvox), imipramine (Tofranil), mirtazapine (Remeron), nefazodone, and nortriptyline (Pamelor)
• Antifungal medicines such as itraconazole (Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend)
• Antipsychotic medicines such as aripiprazole (Abilify), asenapine (Saphris), chlorpromazine, clozapine (Clozaril, FazaClo), fluphenazine, haloperidol (Haldol), iloperidone (Fanapt), lurasidone (Latuda), olanzapine (Zyprexa), paliperidone (Invega), perphenazine, pimozide (Orap), promethazine, quetiapine (Seroquel), risperidone (Risperdal), thioridazine, trifluoperazine and ziprasidone (Geodon)
• Antiseizure medicines such as carbamazepine (Carbatrol, Epitol, Equetro, Tegretol), methsuximide (Celontin), phenobarbital, phenytoin (Dilantin, Phenytek), and valproic acid (Depacon, Depakene, Depakote)
• Atomoxetine (Strattera)
• Bupropion (Aplenzin, Forfivo, Wellbutrin, Buproban, Zyban)
• Corticosteroids such as betamethasone, cortisone, dexamethasone, fludrocortisone, hydrocortisone (A-Hydrocort, Cortef), methylprednisolone (Medrol, Solu-Medrol), prednisolone (Omnipred, Orapred, Prelone), prednisone (Prednisone Intensol), and triamcinolone (Aristospan, Kenalog)
• Diabetes medicines such as acarbose (Precose), glimepiride (Amaryl), glipizide (Glucotrol), glyburide (Glynase), insulin, linagliptin (Tradjenta), metformin (Fortamet, Glucophage, Riomet), miglitol (Glyset), nateglinide (Starlix), pioglitazone (Actos), repaglinide (Prandin), rosiglitazone (Avandia), saxagliptin (Onglyza), and sitagliptin (Januvia)
• Disulfiram (Antabuse)
• Levodopa/carbidopa (Duopa, Rytary, Sinemet)
• Linezolid (Zyvox)
• MAO inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate) (Do not take this medicine and an MAO inhibitor within 14 days of each other.)
• Medicines to treat or prevent blood clots such as apixaban (Eliquis), cilostazol (Pletal), clopidogrel (Plavix), dronedarone (Multaq), rivaroxaban (Xarelto), and warfarin (Coumadin)
• Pain medicines such as codeine, fentanyl (Abstral, Actiq, Duragesic, Fentora, Sublimaze), hydrocodone (Hysingla, Zohydro), hydromorphone (Dilaudid, Exalgo), meperidine (Demerol), methadone (Dolophine, Methadose), morphine (Kadian, MS Contin), oxycodone (OxyContin, Roxicodone), oxycodone/acetaminophen (Percocet, Roxicet), pentazocine (Talwin), tapentadol (Nucynta), and tramadol (ConZip, Ultram)
• Paroxetine (Brisdelle, Paxil, Pexeva)
• Pentamidine (NebuPent, Pentam)
• Rifampin (Rifadin)
• Tamoxifen
• Theophylline

Severe reactions may happen if you eat foods with a lot of tyramine. Use caution with the foods listed. They can cause a reaction that includes a severe headache, large pupils, neck stiffness, nausea, vomiting, diarrhea, flushing, sweating, itching, irregular heartbeat, and chest pain.

• Aged cheeses
• Avocados, bananas, figs, raisins
• Beer, ale
• Caffeine in food, drinks, or medicines
• Chocolate
• Meats prepared with tenderizer, liver, bologna, pepperoni, salami, sausage, meat extracts, caviar, dried or pickled fish, and tuna
• Red wine
• Sour cream and yogurt
• Soy products
• Yeast

Do not drink alcohol while you are taking this medicine.

If you are not sure if your medicines might interact, ask your pharmacist or healthcare provider. Keep a list of all your medicines with you. List all the prescription medicines, nonprescription medicines, supplements, natural remedies, and vitamins that you take. Be sure that you tell all healthcare providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.

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This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your healthcare provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.