Isoniazid
Brand name Rimifon
Used in the following combined preparations Rifater, Rifinah, Rimactazid
General Information
Isoniazid (also known as INAH) has been in use for over 30 years and remains an effective drug for tuberculosis. It is given alone to prevent tuberculosis and in combination with other drugs for the treatment of the disease. Treatment usually lasts for six months. However, courses lasting nine months or a year may sometimes be prescribed.
One of the side effects of isoniazid is the increased loss of pyridoxine (vitamin B6) from the body. This effect, which is more likely with high doses, is rare in children but common among people with poor nutrition. Since pyridoxine deficiency can lead to irreversible nerve damage, supplements are usually given.
Information for Users
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets, liquid, injection.
Frequency and timing of doses
Normally once daily.
Dosage range
Adults 300mg daily.
Children According to age and weight.
Onset of effect
Over 2-3 days.
Duration of action
Up to 24 hours.
Diet advice
Isoniazid may deplete pyridoxine (vitamin B6) levels in the body, so supplements are usually prescribed.
possible adverse effects
Storage
Keep in a closed container in a cool, dry place out of the reach of children. Protect from light.
Missed dose
Take as soon as you remember. If your next dose is scheduled within 8 hours, take a single dose now and skip the next.
Stopping the drug
Take the full course. Even if you feel better the infection may still be present and may recur if treatment is stopped too soon.
Overdose Action
Seek immediate medical advice in all cases. Take emergency . action if breathing difficulties, fits, or loss of consciousness occur.
See Drug poisoning emergency guide.
Although serious problems are uncommon, all adverse effects of this drug should receive
prompt medical attention because of the possibility of nerve or liver damage.
Possible Adverse Effects
Anticonvulsants
The effects of these drugs may be increased with isoniazid.
Antacids
These drugs may reduce the absorption of isoniazid.
Quick Reference
Drug group Antituberculous drug
Overdose danger rating High
Dependence rating Low
Prescription needed Yes
Available as generic Yes
Special Precautions
Be sure to tell your doctor if:
You have long-term liver or kidney problems.
You have had liver damage following isoniazid treatment In the past.
You have diabetes.
You have had epileptic fits.
You are taking other medications.
Pregnancy
Safety in pregnancy not established. Discuss with your doctor.
Breast-feeding
The drug passes into the breast milk and may affect the baby. The infant should be monitored for signs of toxic effects. Discuss with your doctor.
Infants and children
Reduced dose necessary.
Over 60
Increased likelihood of adverse effects.
Driving and hazardous work
No special problems.
Alcohol
Avoid excessive amounts. Large quantities may reduce the effectiveness of isoniazid.
Prolonged Use
Pyridoxine (vitamin B6) deficiency may occur with prolonged use and lead to nerve damage. Supplements are usually prescribed. There is also a risk of serious liver damage.
Monitoring
Periodic blood tests are usually performed to monitor liver function.
