ANTIFUNGALS, ANTIHISTAMINES, AND ANTIMALARIAL AGENTS
Section I. ANTIFUNGALS
A fungus is a plant-like organism of the same class to which mushrooms and
molds belong. They are everywhere in our environment, and those that cause systemic
infection are often geographically limited. Although fungi are common plant pathogens,
only about 50 of the thousands of known species are pathogenic to humans. An
antifungal is an agent that destroys or prevents the growth of fungi. Some agents are
used topically while others are used systemically. The successful treatment of fungal
infections depends on accurate identification of the offending fungus, followed by proper
selection and use of an antifungal drug. Most superficial infections can be adequately
treated with topical therapy. Deep seated infections of the hair or nails generally require
systemic therapy. Systemic fungal infections require the use of orally or intravenously
administered drugs, some of which are toxic.
Various drugs are used to treat fungus.
a. Tolnaftate (Tinactin). This agent is a topical antifungal and is used in the
treatment of athlete's foot, jock itch, and ringworm. The dosage of the drug depends on
the extent of the affected area. Tolnaftate is available as a solution, cream, powder,
and aerosol powder. All containers should be labeled "FOR EXTERNAL USE ONLY."
b. Nystatin (Mycostatin). Nystatin is active in vitro against a number of
yeasts and molds that cause "diaper rash," thrush, and vaginal candidiasis. Nystatin is
relatively nontoxic, but nausea, vomiting, and diarrhea may occur with oral therapy.
This drug has staining properties, and patients using the drug should be cautioned.
Nystatin is available as an ointment, in oral suspension, vaginal cream, vaginal tablets,
and oral tablets.
c. Undecylenic Acid (Desenex). This drug is an antifungal agent employed
in the treatment of superficial fungus infections of the skin. Since it is only fungistatic
and not fungicidal, attention must be given to other forms of hygiene. This agent may
cause irritation on raw lesions; therefore, astringents are used to assist in reducing the
rawness and irritation. An example of such an astringent is zinc, which may be
incorporated into ointments, powders, and aerosols.