The isoniazid-induced peripheral neuropathy occurring in adult tuberculous patients results from a deficiency of biologically active pyridoxine. The deficiency is caused by the combination of isoniazid and pyridoxine to form a hydrazone which is excreted in the urine .
How does isoniazid cause vitamin B6 deficiency?
Second, INH inhibits the enzyme pyridoxine phosphokinase; this enzyme is necessary to activate pyridoxine to pyridoxal 5′ phosphate, the cofactor in many “pyridoxine-dependent” reactions. Functional pyridoxine deficiency is the likely mechanism of INH-induced peripheral neuropathy .
How does isoniazid affect vitamin B6?
Isoniazid can interfere with the activity of vitamin B6 . Vitamin B6 supplementation is recommended, especially in people with poor nutritional status, to prevent development of isoniazid-induced peripheral neuritis (inflamed nerves). One case is reported in which injectable vitamin B6 reversed isoniazid-induced coma.
How does isoniazid affect pyridoxine?
First, INH metabolites directly inactivate pyridoxine species . It also acts by inhibiting the enzyme pyridoxine phosphokinase which is a necessary enzyme to convert pyridoxine to its active form of pyridoxal 5′ phosphate which is a very important cofactor in many reactions.
How does isoniazid cause neurotoxicity?
The increased sensitivity of the dialysis population to isoniazid neurotoxicity is predominantly due to abnormal metabolism of pyridoxine resulting in low serum levels of the active metabolite , pyridoxal phosphate.
What are the symptoms of low vitamin B6?
In adults, vitamin B6 deficiency can cause inflammation of the skin (dermatitis) and a red, greasy, scaly rash . The hands and feet may feel numb and prickling—like pins and needles. The tongue may become sore and red, and cracks may form in the corners of the mouth. People may become confused, irritable, and depressed.
Why do TB patients take vitamin B6?
Vitamin B6 is used to prevent numbing and tingling of the hands or feet sometimes caused by isoniazid or other TB medicines. When should I take this? take the medicine.
Which is a serious side effect of isoniazid?
Tell your doctor right away if any of these rare but serious side effects occur: increased thirst/urination, vision changes , easy bruising/bleeding, mental/mood changes (such as confusion, psychosis), seizures. A very serious allergic reaction to this drug is rare.
What does vitamin B6 do for you?
Vitamin B6 helps maintain a normal amount of this amino acid in your blood. A stronger immune system . Vitamin B6 helps chemical reactions in the immune system, helping it work better. Eating foods rich in vitamin B6 will help your body guard against infection.
What is the result of pyridoxine deficiency?
Pyridoxine deficiency causes blood, skin, and nerve changes . This vitamin is unique in that either deficiency or excess can cause peripheral neuropathy.
Why do you need vitamin B6 with isoniazid?
Vitamin B6 (pyridoxine) supplementation during isoniazid (INH) therapy is necessary in some patients to prevent the development of peripheral neuropathy .
How can I increase my B6 levels?
The richest sources of vitamin B6 include fish, beef liver and other organ meats , potatoes and other starchy vegetables, and fruit (other than citrus). In the United States, adults obtain most of their dietary vitamin B6 from fortified cereals, beef, poultry, starchy vegetables, and some non-citrus fruits [1,3,5].
Can isoniazid cause eye problems?
BACKGROUND: Isoniazid (INH) is an antituberculosis drug that can cause rare but clinically significant ocular side effects . Visual loss is secondary to optic neuropathy, which is usually reversible, although there are many cases of permanent blindness.
Does isoniazid cause liver damage?
Even with monitoring, isoniazid remains a major cause of acute liver failure due to idiosyncratic reactions , and is associated with several instances of acute liver failure and death or emergency liver transplanation in the United States each year.
Can isoniazid cause nerve damage?
Damage to nerves (peripheral neuropathy) may occur with isoniazid and cause numbness and tingling of the hands or feet (parethesia). Other rare side effects related to the nervous system include: Encephalopathy (inflammation of the brain) Optic neuritis (inflammation of the nerve coming from the eye)
Why does isoniazid cause hepatitis?
Chronic INH hepatotoxicity results in the induction of hepatocyte apoptosis , with associated disruption of mitochondrial membrane potential and DNA strand breaks. The most likely biochemical mechanism is that the metabolism of INH produces reactive metabolites that bind and damage cellular macromolecules in the liver.
