A crystalline antibacterial compound, C6H7N3O, used in the treatment of tuberculosis.
[isoni(cotinic acid), isomer of nicotinic acid (ISO- + NICOTINIC ACID) + (hydr)azid(e) (HYDR(O)- + AZ(O)- + -IDE).]
isoniazid
Dictionary:
i·so·ni·a·zid (ī'sə-nī'ə-zĭd)  |
n.
| 5min Related Video: isoniazid |
| Dental Dictionary: isoniazid |
n
INH
trade names: Laniazid, Nydrazid; drug class: antitubercular; action: bactericidal interference with lipid, nucleic acid biosynthesis; uses: treatment and prevention of tuberculosis.
| Drug Info: Isoniazid, INH |
Brand names: Isoniazid, INHNydrazid®
Chemical formula:
- Drug Forms:
- Isoniazid, INH tablets (below)
- Isoniazid, INH injection
- Isoniazid Solution for injection
- Isoniazid Oral tablet
- Isoniazid Oral solution
- Español:
- Tabletas de isoniazida, INH
- Inyección de isoniazida, INH
- Isoniazida, Solución para inyección
- Isoniazida, Tableta oral
- Isoniazida, Solución oral
Isoniazid, INH tablets
What are isoniazid tablets?
ISONIAZID (INH™) is used to treat or prevent tuberculosis. For treatment of tuberculosis, other medicines may be used together with isoniazid. For prevention of tuberculosis, isoniazid may be given alone. Generic isoniazid tablets are available.
What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:
• acne
• diabetes mellitus
• kidney disease
• if you frequently drink alcohol-containing beverages
• liver disease
• malnutrition
• seizures (convulsions)
• tingling of the fingers or toes, or other nerve disorder
• an unusual or allergic reaction to isoniazid, other medicines, foods, dyes or preservatives
• pregnant or trying to get pregnant
• breast-feeding
How should I take this medicine?
Take isoniazid tablets by mouth. Follow the directions on the prescription label. Swallow tablets whole with a full glass of water. Take isoniazid on an empty stomach; 1 to 2 hours before food, or at least 2 hours after food. Take your doses at regular intervals and try not to miss any doses. Do not take your medicine more often than directed. Finish the full course prescribed by your prescriber or health care professional even if you think your condition is better. Do not stop taking except on your prescriber's advice.
What drug(s) may interact with isoniazid?
• carbamazepine
• chlorzoxazone
• cycloserine
• diazepam
• disulfiram
• doxercalciferol
• furazolidone
• histamine-containing foods (examples: aged cheeses and fish such as tuna, skipjack, sardinella and especially raw fish or spoiled fish)
• hormones such as prednisone or cortisone
• itraconazole
• linezolid
• medicines called MAO inhibitors-phenelzine (Nardil®), tranylcypromine (Parnate®), isocarboxazid (Marplan®), selegiline (Eldepryl®)
• medicines for diabetes
• paricalcitol
• phenytoin
• procarbazine
• rifampin
• some medications for Parkinson's disease, such as entacapone, levodopa or tolcapone
• tyramine-containing foods (such as cheeses; meats and fish, especially those that are aged, smoked, pickled, or processed; beer and ale; wine; avocados; bananas; figs; raisins; soy sauce; miso soup; yeast extract; and bean curd)
• valproic acid
• voriconazole
• warfarin
Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.
What should I watch for while taking isoniazid?
Keep taking your isoniazid even if you feel better. You may need to take this medicine for a long time. Visit your prescriber or health care professional for regular checks; tell him of any change in your vision. Report any other side effects promptly.
Ask your prescriber or health care professional if you need to take pyridoxine, vitamin B6. Isoniazid can make your body short of this vitamin.
Avoid alcoholic drinks while you are taking isoniazid. Alcohol can increase the damage to your liver from isoniazid.
An interaction between isoniazid and certain foods can make you feel ill (see interactions' list). If you get red or itching skin, fast heartbeat, sweat, get chills or feel clammy, feel lightheaded and have a headache, do not treat yourself. Call your prescriber or health care professional as soon as you can and avoid these foods.
Antacids can prevent isoniazid from working correctly. If you get an upset stomach and want to take an antacid, make sure there is an interval of at least 2 hours since you last took isoniazid, or at least 4 hours before your next dose.
If you are diabetic, you may get a false-positive result for sugar in your urine. Check with your prescriber or health care professional before you change your diet or the dose of your diabetic medicine.
What side effects may I notice from taking isoniazid?
Elderly patients are more likely to get side effects.
Side effects that you should report to your prescriber or health care professional as soon as possible:
• blood in urine
• blurred vision, eye pain
• changes in how you see color (especially seeing the difference between red and green)
• clumsiness, unsteadiness
• dark yellow or brown urine
• difficulty breathing
• fever or chills, sore throat
• headache
• loss of appetite
• nausea, vomiting
• reduced amount of urine passed
• seizures (convulsions)
• skin rash, itching
• stomach pain
• tingling, pain, or numbness in the hands or feet
• unusual bleeding or bruising
• unusual tiredness or weakness
• yellowing of the eyes or skin
Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
• diarrhea
• upset stomach
Where can I keep my medicine?
Keep out of the reach of children in a container that small children cannot open.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Protect from light. Keep container tightly closed. Throw away any unused medicine after the expiration date.
Last updated: 7/1/2002
Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.
| Columbia Encyclopedia: isoniazid |
isoniazid (ī'sōnī'əzĭd), drug used to treat tuberculosis. Also known as isonicotinic acid hydrazide, isoniazid is the most effective antituberculosis drug currently available. The drug inhibits or kills the tubercle bacilli that cause the disease. It is usually given together with some other antituberculosis drug such as streptomycin or aminosalicylic acid to prevent emergence of drug resistant organisms (see drug resistance). To prevent development of tuberculosis in individuals who have a positive reaction to a tuberculin skin test, isoniazid is given alone. Side effects are seen only with very high doses.
| Veterinary Dictionary: isoniazid |
An antibacterial compound used in treatment of tuberculosis and opportunistic mycobacterial infections.
| Wikipedia: Isoniazid |
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Isoniazid
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| Systematic (IUPAC) name | |
| isonicotinohydrazide | |
| Identifiers | |
| CAS number | 54-85-3 |
| ATC code | J04AC01 |
| PubChem | 3767 |
| DrugBank | APRD01055 |
| ChemSpider | 3635 |
| Chemical data | |
| Formula | C6H7N3O |
| Mol. mass | 137.139 g/mol |
| SMILES | eMolecules & PubChem |
| Pharmacokinetic data | |
| Bioavailability | ? |
| Protein binding | Very low (0-10%) |
| Metabolism | liver; CYP450: 2C19, 3A4 inhibitor |
| Half life | 0.5-1.6h (fast acetylators), 2-5h (slow acetylators) |
| Excretion | urine (primarily), feces |
| Therapeutic considerations | |
| Pregnancy cat. |
C |
| Legal status |
prescription only (US) |
| Routes | oral, intramuscular, intravenous |
 (what is this?) (verify) |
|
Isoniazid (also called isonicotinyl hydrazine or INH; sold as Laniazid, Nydrazid) is an organic compound that is the first-line antituberculosis medication in prevention and treatment. First discovered in 1912 as an inhibitor of the MAO enzyme, it was first used as an antidepressant, but discontinued due to side effects. In 1951, it was later discovered that isoniazid was effective against TB. Isoniazid is never used on its own to treat active tuberculosis because resistance quickly develops.
The compound was first synthesised in the early 20th century,[1] but its activity against tuberculosis was first reported in the early 1950's and three pharmaceutical companies attempted unsuccessfully to simultaneously patent the drug[2] (most prominently, Roche, who launched their version, Rimifon, in 1952). With the introduction of isoniazid, a cure for tuberculosis was first considered reasonable.
Isoniazid is available in tablet, syrup, and injectable forms (given intramuscularly or intravenously). Isoniazid is available worldwide, is inexpensive and is generally well tolerated. It is manufactured from isonicotinic acid, which is produced from 4-methylpyridine.[3]
Contents |
Preparation
Isoniazid may be prepared by the base hydrolysis of 4-cyanopyridine to give the amide, followed by displacement of ammonia by hydrazine:[4]
Mechanism of action
Isoniazid is a prodrug and must be activated by bacterial catalase.[5] It is activated by catalase-peroxidase enzyme KatG which couples the isonicotinic acyl with NADH to form isonicotinic acyl-NADH complex. This complex binds tightly to ketoenoylreductase known as InhA, thereby blocking the natural enoyl-AcpM substrate and the action of fatty acid synthase. This process inhibits the synthesis of mycolic acid required for the mycobacterial cell wall. A range of radicals are produced by KatG activation of Isoniazid, including nitric oxide,[1] that has also been shown to be important in the action of another antimycobacterial prodrug PA824 [2].
Isoniazid is bactericidal to rapidly-dividing mycobacteria but is bacteriostatic if the mycobacterium is slow-growing. Isoniazid inhibits the P450 system.
Metabolism
Isoniazid reaches therapeutic concentrations in serum, cerebrospinal fluid (CSF), and within caseous granulomas. Isoniazid is metabolized in the liver via acetylation. There are two forms of the enzyme responsible for acetylation, so that some patients metabolize the drug more quickly than others. Hence, the half-life is bimodal with peaks at 1 hour and 3 hours in the US population. The metabolites are excreted in the urine. Doses do not usually have to be adjusted in case of renal failure.
Dosing
The standard dose of isoniazid in adults is 5 mg/kg/day (max 300mg daily). When prescribed intermittently (twice or thrice weekly) the dose is 15mg/kg (max 900mg daily). Patients with slow clearance of the drug (via acetylation as described above) may require reduced dosages to avoid toxicity. The recommended dose for children is 8 to 12 mg/kg/day.[6]
Side effects
Adverse reactions include rash, abnormal liver function tests, hepatitis, sideroblastic anemia, peripheral neuropathy, mild central nervous system (CNS) effects, drug interactions resulting in increased phenytoin (Dilantin) or disulfiram (Antabuse) levels and intractable seizures (status epilepticus).
Peripheral neuropathy and CNS effects are associated with the use of isoniazid and are due to pyridoxine (vitamin B6) depletion, but are uncommon at doses of 5 mg/kg. Persons with conditions in which neuropathy is common (e.g., diabetes, uremia, alcoholism, malnutrition, HIV-infection), as well as pregnant women and persons with a seizure disorder, may be given pyridoxine (vitamin B6) (10-50 mg/day) with isoniazid.
Hepatotoxicity can be avoided with close clinical monitoring of the patient, specifically nausea, vomiting, abdominal pain and appetite. Isoniazid is metabolized by the liver mainly by acetylation and dehydrazination. The N-acetylhydrazine metabolite is believed to be responsible for the hepatotoxic effects seen in patients treated with isoniazid. The rate of acetylation is genetically determined. Approximately 50% of blacks and Caucasians are slow inactivators; the majority of Inuit and Asians are rapid inactivators. The half-life in fast acetylators is 1 to 2 hours while in slow acetylators it is 2 to 5 hours. Elimination is largely independent of renal function, however the half-life may be prolonged in liver disease. The rate of acetylation has not been shown to significantly alter the effectiveness of isoniazid. However, slow acetylation may lead to higher blood concentrations with chronic administration of the drug, with an increased risk of toxicity. Isoniazid and its metabolites are excreted in the urine with 75 to 95% of the dose excreted in 24 hours. Small amounts are also excreted in saliva, sputum and feces. Isoniazid is removed by hemodialysis and peritoneal dialysis.[3]
Headache, poor concentration, poor memory and depression have all been associated with isoniazid use. The frequency of these side effects is not known, and the association with isoniazid is not well validated. On the other hand, all patients and health-care workers should be aware of this serious adverse effect, especially if suicidal thinking or behavior occurs. [4] [5] [6]
INH therapy will decrease the efficacy of hormonal birth control when combined with Rifampin.
Synonyms and abbreviations
- Isonicotinyl hydrazine
- Isonicotinic acid hydrazide
- INH
- H (for "hydrazide", and also the WHO standard abbreviation)
See also
References
- ^ Meyer H, Mally J. "On hydrazine derivatives and pyridine carbonic acids" (in German). Monatshefte Chemie verwandte Teile anderer Wissenschaften 23: 393–414.
- ^ Hans L Riede (2009). "Fourth-generation fluoroquinolones in tuberculosis". Lancet 373 (9670): 1148–1149. doi:.
- ^ Shinkichi Shimizu, Nanao Watanabe, Toshiaki Kataoka, Takayuki Shoji, Nobuyuki Abe, Sinji Morishita, Hisao Ichimura (2007). "Pyridine and Pyridine Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. New York: John Wiley & Sons.
- ^ T. P. Sycheva, T. N. Pavlova and M. N. Shchukina (1972). "Synthesis of isoniazid from 4-cyanopyridine". Pharmaceutical Chemistry Journal 6 (11): 696-698. doi:.
- ^ Timmins GS, Deretic V (2006). "Mechanisms of action of isoniazid". Mol. Microbiol. 62 (5): 1220–7. doi:. PMID 17074073. http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-2958.2006.05467.x.
- ^ McIlleron H, Willemse M, Werely CJ, et al. (2009). "Isoniazid plasma concentrations in a cohort of South African children with tuberculosis: Implications for international pediatric dosing guidelines". Clin Infect Dis 48 (11): 1547–1553. doi:.
External links
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- Core Curriculum on Tuberculosis (2000) Division of Tuberculosis Elimination, Centers for Disease Control and Prevention
- See Chapter 6, Treatment of LTBI Regimens - Isoniazid::
See Chapter 7 - Treatment of TB Disease Monitoring - Adverse Reactions to First-Line TB Drugs - Isoniazid::
See Table 5 First-Line Anti-TB Medications
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- Isoniazid Overdose: Recognition and Management American Family Physician 1998 Feb 15
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| Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/. Read more |
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Mentioned in
- INH (trademark)
- antitubercular agent (pharmacology)
- acetylator
- Isoniazid, INH tablets
