How Do Antileprosy Agents Work?

Antileprosy agents are a class of drugs used to treat leprosy and certain skin infections such as dermatitis herpetiformis (a bumpy, itchy skin rash that is common in people with celiac disease). Leprosy is an infectious disease (caused by the bacterium Mycobacterium leprae) that causes severe disfiguring skin sores and nerve damage in the arms, legs, and skin areas around the body. The only drug that belongs to this class is dapsone-- a sulfone active agent with anti-inflammatory immunosuppressive properties and antibacterial and antibiotic properties. Dapsone may be used alone or with other medications. It is the principal drug in a multidrug regimen recommended by the World Health Organization for the treatment of leprosy.

Antileprosy agents are administered orally in the form of tablets. They are usually taken either once a day or three times a week with or without food.

Antileprosy agents work in the following ways:

• They are anti-infective medications that fight bacteria and interfere with the proliferation of the bacterium that causes leprosy (Mycobacterium leprae).
• They work by decreasing swelling (inflammation) and stopping the growth of bacteria.

Their mechanism of action, which is very similar to sulfonamides, is as follows:

• Humans and bacteria both need folic acid, a naturally occurring B vitamin, to make DNA and other genetic material.
• Bacteria need to synthesize it for their cell formation (nucleic acid synthesis).
• Antileprosy agents interfere in the folic acid synthesis in bacterial cells due to their structural similarity to para-aminobenzoic acid (PABA).
• PABA inhibits dihydropteroate synthase, an enzyme that facilitates PABA as a substrate for the synthesis of dihydrofolic acid (folic acid).
• Inhibition of folic acid stops the cell formation in bacteria, thereby preventing their growth and reproduction.

Antileprosy agents are used in conditions such as:

• Leprosy (a contagious disease that affects the skin, mucous membranes, and nerves, causing discoloration and lumps on the skin and in severe cases, disfigurement and deformities)
• Dermatitis herpetiformis (a bumpy, itchy skin rash that is common in people with celiac disease)
• Tuberculoid or lepromatous disease (patients with tuberculoid leprosy have limited disease and relatively few bacteria in the skin and nerves, whereas lepromatous patients have a widespread disease and large numbers of bacteria)
• Pneumocystis carinii pneumonia (an opportunistic infection that occurs in immunosuppressed populations, primarily patients with AIDS infection)

Some of the common side effects include:

• Nausea
• Vomiting
• Loss of appetite
• Dizziness (feeling faint, weak, or unsteady)
• Blurred vision
• Insomnia (trouble falling and/or staying asleep)
• Headache
• Upset stomach
• Tinnitus (ringing or other noises in one or both ears)

Other rare side effects include:

• Methemoglobinemia (a condition in which a higher-than-normal amount of methemoglobin is found in the blood. Methemoglobin is a form of hemoglobin that cannot carry oxygen)
• Fast heartbeat/breathing
• Bluish lips/skin
• Exfoliative dermatitis (redness and peeling of the skin over large areas of the body)
• Muscle weakness
• Leukopenia (reduced number of white blood cells)
• Hepatitis (an inflammatory condition of the liver)
• Cholestatic jaundice (characterized by the yellow coloration of the skin and eyes, dark urine, light-colored stools, and generalized itchiness)
• Severe abdominal/chest pain
• Easy bruising
• Unusual thoughts or behavior
• Peripheral neuropathy (a condition in which nerves that carry messages to and from the brain and spinal cord from and to the rest of the body are damaged or diseased)
• Systemic lupus erythematosus (a chronic autoimmune disease that can cause severe fatigue and joint pain)
• Signs of infection:
  • Sore throat
  • Fever
  • Rash
  • Chills
  • Swelling in the face or tongue
  • Shortness of breath

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug name includes:

• Dapsone