| > | | | | is a bacteriostatic drug. It is used as an adjunct to |
| Pyrazinamide (Pza, Pyraldina, Pyzina) | | | | the bactericidal anti-tuberculosis drugs, isoniazid and |
| It has become a first line drug in recent years, | | | | rifampicin. It has good patient acceptance and fewer |
| specially for short course chemotherapy of | | | | adverse effects, and has therefore replaced |
| tuberculosis. It is also used for conventional | | | | aminosalicylic acid (described later). It is considered to |
| chemotherapy by some doctors along with rifampicin | | | | be a substitute for injected Streptomycin. It |
| and isoniazid until the results of susceptibility studies | | | | prevents development of resistance during |
| are available (8 weeks), specially when resistance to | | | | treatment. |
| isoniazid is suspected. It kills (bactericidal) the | | | | Adverse Effects: Ethambutol causes a dose-related |
| intracellular tubercle. Its use with other drugs reduces | | | | toxic effect on the eyes. After an initial dose of 25 |
| relapse significantly. | | | | mg/kg daily for 2 months, followed by 15 mg/kg daily |
| Adverse Effects: It causes dose related | | | | for several months, there may be diminution of vision |
| hepatotoxicity. But this which is less common in the | | | | or loss of color perception in about 1% cases. This |
| subcontinent. The currently used smaller dose of this | | | | adverse effect reverses within a few months of |
| drug (25 mg/kg daily) rarely causes hepatotoxicity, | | | | stopping the drug. In rare cases, the recovery is |
| especially when used for a short period of 2 months. | | | | delayed for one year or more. The toxicity increases |
| It causes an increase in the uric acid in the blood | | | | in patients with impaired kidney function. Other |
| (hyperuricemia) and may cause gouty pains in joints. | | | | adverse effects include numbness or decreased |
| If the symptoms in the gout (pain in joints) occur, | | | | sensation in the legs, headache, confusion, and |
| the drugs which increase excretion of uric acid may | | | | increased uric acid levels. Since children (below 6 |
| be used along with it. Sometimes diabetes becomes | | | | years) cannot report the changes in visual acuity |
| worse with its use. Skin rash and fever may also | | | | exactly, ethambutol should not be used for childhood |
| occur. | | | | tuberculosis. |
| Precautions | | | | Precautions |
| Serum enzymes should be measured every 2 to 4 | | | | A complete examination of the eyes should be done |
| weeks to assess the liver function. | | | | before starting this drug. It should not be used if |
| If you develop any pain in the joints, ask the doctor | | | | there is optic nerve damage. |
| to recommend drugs which increase uric acid | | | | The doctor should be informed immediately if any |
| excretion. | | | | adverse effects like numbness or headache occur. |
| Avoid its use during pregnancy and lactation. | | | | If higher doses are taken for a prolonged period, eye |
| Ethambutol (Myambutol, Combutol, Themibutol) | | | | examination should be repeated an drug should be |
| Since this inhibits the synthesis of cell metabolites, | | | | stopped if changes in visual fields occur. |
| resulting in inhibition of the growth of tubercle bacilli, it | | | | |