Pharmacology for Dentistry

370 Section 9/ Chemotherapy

Adverse effects include haemolysis
which is most common and dose related.
Patients with G-6-PD deficiency are more
susceptible. Nausea, vomiting, anorexia,
headache, methaemoglobinaemia, drug
fever, allergic skin reactions, insomnia and
paresthesia. Rarely hepatitis and
agranulocytosis.

It is also used with pyrimethamine in
chloroquine resistant malaria.

PHENAZINE DERIVATIVES

CLOFAZIMINE

Clofazimine is phenazine dye and used
as alternative to dapsone in dapsone
intolerant/resistant cases and in
combination with dapsone and rifampicin
in the multidrug treatment of leprosy. It’s
probable mechanism of action is its
involvement in DNA binding, it may
interfere with template function of DNA.

After oral administration, it is slowly
absorbed, stored widely in reticuloendot-
helial system and fatty tissues. It has long
elimination half life.

Adverse effects include discolouration
of skin (red brown to black) and skin lesion
persists for month after discontinuation of
therapy. Other side effects include dry skin,
itching, phototoxicity, nausea, abdominal
pain, anorexia and diarrhoea.

ANTITUBERCULAR DRUGS

RIFAMPICIN

It is bactericidal and highly effective in
leprosy. A single monthly dose of 600 mg
may be used in combination with other
antileprosy drugs to avoid any probable
risk of rifampicin resistant M. leprae.

The detailed pharmacology is discussed

in chapter ‘Chemotherapy of Tuberculosis’.

ETHIONAMIDE

It is antitubercular drug used as an

alternative to clofazimine in the treatment

of leprosy. But due to its hepatotoxicity, its

use in leprosy is very limited.

OTHER ANTIMICROBIAL AGENTS

Among fluoroquinolones, ofloxacin,

pefloxacin and sparfloxacin can be used in

alternative regimen, when drugs like

rifampicin can not be used. Detailed

pharmacology of quinolones is discussed in

chapter ‘Sulfonamides, nitrofurans and

quinolones’.

Among macrolide antibiotics,

clarithromycin is effective against M. leprae

as an alternative multidrug therapy (MDT)

regimen (detailed pharmacology is

discussed in ‘Macrolide antibiotics’).

MINOCYCLINE

It is a tetracycline which is active

against M. leprae and its bactericidal

activity is higher than that of

clarithromycin. Used in alternative

multidrug treatment regimen (MDT).

CLARITHROMYCIN

Only macrolide antibiotic useful in

leprosy. It is used in alternative MDT regimen.

Recently, thalidomide (50-100 mg

capsule form, approved by FDA), an

immunomodulatory agent is used in

erythema nodosum leprosum (ENL) which

is a complication of leprosy occurring in

approximately one half of borderline

lepromatous and lepromatous leprosy

patients.