Isoniazid 300mg tablet, use, side effects || pharmacyteach.com
Generic name : Isoniazid
Brand name : Myrin-P, rifapin-H 300mg, Rifinah 300mg
Introduction
Isoniazid is an antibiotic medication approved by U.S. Food
and Drug Administration (FAD) used to treat tuberculosis (TB) and to prevent
the spread of TB to others. Isoniazid involves in the first line of TB treatment. It
works by inhibiting the growth and reproduction of the bacteria that cause
tuberculosis. Isoniazid is taken in combination with rifampin, Ethambutol, and pyrazinamide.
Isoniazid is very effective for fast-multiplying organisms.
It kills fast-multiplying organisms and inhibits the growth of the resting organisms. It is
effective for both extracellular and intracellular (bacilli present inside the macrophage) and
shows activity in both acidic and basic mediums.
Isoniazid only uses for tubercular mycobacteria infection it
is not workable for non-tubercular mycobacteria and viral infections.
Isoniazid is usually taken orally. The medication must be
taken for several months to be effective, as TB bacteria are slow-growing and difficult to eradicate.
Mechanism of action
The mechanism of action of isoniazid involves the inhibition
of mycolic acid synthesis in the cell wall of the tuberculosis bacterium.
Mycolic acids are long fatty acids that are a key component of the cell wall of
Mycobacterium tuberculosis, the bacterium that causes tuberculosis.
Isoniazid is a pro-drug meaning it is inactive form when
administered and become active by enzymatic metabolism (catalase-peroxidase)
Isoniazid works by targeting a specific enzyme, called InhA
and KasA, which is involved in synthesizing mycolic acids. Specifically,
isoniazid binds to the active site of the enzyme and inhibits its activity,
which disrupts the biosynthesis of mycolic acids and weakens the bacterial cell
wall. This results in the bacterium being unable to grow and divide and
ultimately leads to its death.
Overall, isoniazid's ability to inhibit the mycolic acid
synthesis and disrupt the bacterial cell wall is a key factor in its
effectiveness against tuberculosis and is the reason why it is often used as a
first-line medication in the treatment of this disease.
Pharmacokinetics of Isoniazid:-
Isoniazid is typically taken orally and is rapidly absorbed
into the bloodstream from the gastrointestinal tract. The drug is distributed
widely throughout the body, including the lungs where the tuberculosis bacteria
can be found. The peak blood concentration of isoniazid is typically achieved
within 1-2 hours after taking the medication.
The drug is metabolized primarily in the liver by
acetylation, where it is converted to acetyl isoniazid and other metabolites by
an enzyme called N-acetyltransferase 2 (NAT2). The acetyl isoniazid is then
further metabolized to several other compounds, some of which are excreted
in the urine.
Fast acetylators (t1/2 of INH is 1 hour.
Slow acetylators(t1l2 of INH is 3 hours.
The half-life of isoniazid is around 1-4 hours, meaning that
it is eliminated from the body relatively quickly. However, the rate of
elimination can be influenced by several factors, including age, liver
function, and other medications that may be taken concurrently.
Isoniazid can also interact with other medications, such as
rifampin and pyridoxine, which may affect its pharmacokinetics. For example,
rifampin can induce the activity of the enzymes responsible for isoniazid
metabolism, which can lead to increased clearance of the drug and reduced effectiveness.
Pyridoxine, a form of vitamin B6, is often co-administered with isoniazid to
prevent peripheral neuropathy, a common side effect of isoniazid, by
replenishing the body's stores of this vitamin.
Overall, the pharmacokinetics of isoniazid can be complex
and can vary depending on individual factors and drug interactions. It is
important to follow healthcare provider instructions for dosing and monitoring
to ensure the medication is effective and safe.
How to take Isoniazid;
Isoniazid is typically taken by mouth as a tablet or
capsule, and the exact dosing and duration of treatment will depend on the
condition being treated and individual patient factors. Here are some general
guidelines for taking isoniazid:
Follow healthcare provider instructions: Always follow the
dosing instructions provided by your healthcare provider, and do not change the
dose or duration of the treatment without their guidance.
Take on an empty stomach: Isoniazid is best taken on an
empty stomach, at least one hour before or two hours after meals.
Take consistently: It is important to take isoniazid
consistently, at the same time each day, to maintain effective levels of the
medication in the body.
Do not crush or chew tablets: Swallow the tablets or
capsules whole with a full glass of water.
Take vitamin B6: To prevent peripheral neuropathy,
healthcare providers may recommend taking vitamin B6 (pyridoxine) supplements
along with isoniazid.
Keep up with appointments: People taking isoniazid may
require regular appointments with their healthcare provider to monitor for
potential side effects or assess treatment effectiveness.
It is important to finish the full course of treatment as
prescribed, even if symptoms improve, to prevent the development of antibiotic
resistance and ensure effective treatment. If you have any questions or
concerns about taking isoniazid, speak with your healthcare provider.
What will be followed Precautions for taking isoniazid?
When taking isoniazid, several precautions should be considered to ensure the safe and effective use of the medication. Some
of these precautions include:
Liver
disease: Isoniazid
is metabolized in the liver, so people with liver disease should be closely
monitored when taking the medication.
Alcohol
consumption: Isoniazid
can increase the risk of liver damage, and alcohol consumption can further
increase this risk. People taking isoniazid should avoid or limit alcohol
consumption.
Peripheral neuropathy: Isoniazid can cause peripheral
neuropathy, which is a condition that causes numbness, tingling, or pain in the
hands and feet. To prevent this, healthcare providers may recommend taking
vitamin B6 (pyridoxine) supplements.
Drug interactions: Isoniazid can interact with other
medications, including rifampin, which is often taken concurrently to treat
tuberculosis. These interactions can affect the effectiveness and safety of
both medications, so it is important to inform your healthcare provider about
all medications you are taking.
Pregnancy and breast-feeding: Isoniazid is generally
considered safe for use during pregnancy and breastfeeding, but it is important
to consult with a healthcare provider before taking the medication to determine
the potential risks and benefits.
HIV infection: People with HIV may require
higher doses of isoniazid and may be at increased risk of side effects.
Overall, it is important to closely follow healthcare
provider instructions when taking isoniazid and to report any potential side
effects or concerns.
Drug-Drug interaction of isoniazid
Isoniazid can interact with other medications, which can
affect its effectiveness and safety. Some examples of drug interactions with
isoniazid include:
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Rifampin: Rifampin is often taken concurrently with
isoniazid to treat tuberculosis, but it can induce the activity of the
enzymes responsible for isoniazid metabolism, which can lead to reduced
effectiveness of isoniazid. |
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Anticonvulsants: Isoniazid can reduce the effectiveness of
some anticonvulsant medications, such as phenytoin and carbamazepine, which
can lead to decreased seizure control. |
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Warfarin: Isoniazid can interact with warfarin, a
blood-thinning medication, and increase the risk of bleeding. |
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Antacids: Antacids can reduce the absorption of
isoniazid, so they should be taken at least one hour before or two hours
after taking isoniazid. |
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Alcohol: Isoniazid can increase the risk of liver
damage, and alcohol consumption can further increase this risk. |
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Other medications: Isoniazid can interact with a wide range of
other medications, including other antibiotics, antifungal medications, and
antidepressants. It is important to inform your healthcare provider about all
medications you are taking before starting isoniazid. |
It is important to closely monitor for potential drug
interactions and to report any concerns or side effects to your healthcare
provider. In some cases, the doses of medications may need to be adjusted or
alternative medications may need to be used to avoid potentially harmful interactions.
Drug-Disease interaction of isoniazid
Isoniazid can interact with certain pre-existing medical
conditions or diseases. Here are some examples of drug-disease interactions
involving isoniazid:
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Liver disease: Isoniazid is metabolized in the liver, so
people with liver disease may be at higher risk of liver damage or toxicity
from the medication. |
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Peripheral neuropathy: Isoniazid can cause peripheral neuropathy,
which is a condition that causes numbness, tingling, or pain in the hands and
feet. People with pre-existing neuropathy may be at higher risk of developing
this side effect. |
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Seizure disorders: Isoniazid can reduce the effectiveness of
some anticonvulsant medications, which can lead to decreased seizure control
in people with seizure disorders. |
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Diabetes: Isoniazid can increase blood sugar levels,
which may require closer monitoring or adjustments in diabetes medications in
people with diabetes. |
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HIV infection: People with HIV may require higher
doses of isoniazid and may be at increased risk of side effects. |
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Gout: Isoniazid can increase the risk of gout
attacks in people with gout. |
It is important to inform your healthcare provider about any
pre-existing medical conditions or diseases before starting isoniazid. In some
cases, the medication may need to be used with caution, and doses or treatment
plans may need to be adjusted to ensure safety and effectiveness.
Why is the drug Isoniazid often written as INH? What does the INH stand for?
Isoniazid is often abbreviated as INH, which stands for
isonicotinylhydrazine. This name reflects the chemical structure of the
medication, which contains an isonicotinyl group and a hydrazine functional
group. The abbreviation INH is commonly used in medical literature, clinical
practice, and pharmaceutical packaging and labeling.
How do I reduce the side effects of Isoniazid?
Some tips to minimize the side effects of isoniazid:
Take vitamin B6: Isoniazid can deplete the body's stores of
vitamin B6 (pyridoxine), which can lead to peripheral neuropathy. Taking
vitamin B6 supplements may help reduce the risk of neuropathy and other side
effects.
Avoid alcohol: It is best to avoid alcohol while taking
isoniazid.
Take with food: While isoniazid is best taken on an empty
stomach, some people may experience less gastrointestinal upset if the
medication is taken with a small amount of food.
What happens if I stop taking isoniazid?
Do not stop taking the medication without a physician's recommendation.
if you facing any problems contact your physician.
When should I stop taking Isoniazid?
You should never stop taking isoniazid or any medication
without consulting with your physician.
Duration of isoniazid treatment can vary depending on the
condition being treated, and stopping the medication prematurely can lead to
treatment failure, relapse, or antibiotic resistance.
It is important to complete the full course of isoniazid
treatment, even if you start to feel better or the symptoms improve. Your
healthcare provider will typically monitor your response to treatment and
advise you on the appropriate duration of treatment. In general, treatment for
active tuberculosis (TB) may take six months or longer, while treatment for
latent TB infection may last for several months.
If you experience any concerning side effects while taking
isoniazid, such as a rash, severe nausea, vomiting, or yellowing of the skin or
eyes, or if you have concerns about the medication, speak with your healthcare
provider. They can assess the situation and determine whether any changes in
the medication or dosage are necessary.
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