OTHER RARE SIDE EFFECTS:
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)
- Atrophy (degeneration) of the nerve coming from the eye
- Impaired memory
- Peripheral neuropathy
Pyridoxine (vitamin B6), 10-50 mg/day, decreases the risk of neural side effects.
The rate at which isoniazid is eliminated by the liver is race-dependent. Thus, 60% of African Americans and whites eliminate isoniazid slowly compared with only 10%-20% of Asians. Individuals who eliminate isoniazid slowly are more prone to develop hepatitis and neural side effects with long-term use of isoniazid.
Other important side effects of isoniazid include:
- Abdominal pain
- Dry skin
- Skin rashes and eruptions
- Swollen lymph nodes
- Reductions in white blood cells (which increases the risk of infection)
- Reductions in platelets (which increases the risk of bleeding)
- High blood sugar levels in the blood
- Gynecomastia (enlargement of the breasts in men)
- Ringing in the ears
- Urinary retention (difficulty passing urine)
- Blood disorders
- Hypersensitivity reactions
- Painful joints
Quick GuideInfectious Mononucleosis (Mono): Symptoms and Treatment
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