Interventions for Tuberculosis Control and Elimination 2002

ability of the drug in the serum of the person to whom the
drug is administered;
• βt 1/2 : the serum elimination half-life (in hours) of the drug. It indicates
the time required to reduce the blood serum (or plasma)
concentration to half of its maximum value.
Dosage. This is the recommended dosage in the treatment of tuberculosis
in daily or thrice-weekly treatment. Because neither WHO nor the IUATLD
recommend twice-weekly treatment, the dosages recommended for such an
administration schedule are not presented.
Adverse drug events. No drug is without side effects or adverse drug
events. Four types of adverse drug events might be distinguished: 15
1) toxic, 2) idiosyncratic, 3) hypersensitivity reactions, and 4) adverse drug
events that cannot be classified into one of the three preceding groups.
Toxic reactions are effects that will occur in the majority of patients at a
given dose. Idiosyncrasy denotes an individual genetic defect that causes
a qualitative abnormal response. 16 Hypersensitivity reactions are untoward
immunologic reactions to a drug.
Interactions. Some drugs interact with other medications. Such interactions
are listed here, to the extent known.
Isoniazid
Discovery. Isoniazid was synthesized in 1912 at the German University
of Prague by Meyer and Mally (figure 5). 17 In 1952 it was independently
re-discovered by the Bayer Laboratories in Germany, 18 Hoffmann-La Roche
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Figure 5. Chemical structure of isoniazid, synthesized by Meyer and Malley in
1912. 17
17