Hetrazan, known generically as diethylcarbamazine or DEC, is a medication used to combat parasitic infections. It belongs to a class of drugs called anthelmintics, targeting several common parasites.
Conditions Hetrazan Treats
Hetrazan treats parasitic infections caused by filarial worms. These include lymphatic filariasis, caused by species such as Wuchereria bancrofti, Brugia malayi, and Brugia timori. Lymphatic filariasis can lead to severe swelling in the arms, legs, breasts, or genitals, known as elephantiasis. The drug is also effective against loiasis, an infection caused by the Loa loa worm, and tropical pulmonary eosinophilia.
Tropical pulmonary eosinophilia is a hypersensitivity reaction to microfilariae trapped in the lungs. This condition often presents with nocturnal coughing, wheezing, and fatigue, and if left untreated, can result in lung damage. While Hetrazan has been used for onchocerciasis, also known as river blindness, ivermectin is generally the preferred treatment due to the risk of severe reactions to Hetrazan.
How Hetrazan Works in the Body
Hetrazan’s mechanism of action primarily involves its effect on the microfilariae, which are the larval forms of the filarial worms. The drug is thought to inhibit the arachidonic acid metabolism in these microfilariae, which makes them more susceptible to the host’s innate immune system. This action does not directly kill the parasites but rather sensitizes them to phagocytosis, a process where white blood cells engulf and destroy foreign particles.
Hetrazan also causes hyperpolarization of the microfilariae’s muscle cells, leading to their paralysis. This immobilization prevents the microfilariae from migrating through the body’s tissues, making them easier targets for the immune system to eliminate. While it primarily targets microfilariae, Hetrazan can also kill adult Loa loa worms and is presumed to kill adult W. bancrofti and B. malayi worms, though not adult O. volvulus worms.
Taking Hetrazan Safely
Hetrazan is typically administered orally, and it is generally recommended to take the medication with meals to minimize gastrointestinal side effects. Dosage and treatment duration vary significantly based on the specific infection, patient body weight, and other individual factors. For example, lymphatic filariasis treatment often involves 6 mg/kg divided into three daily doses for 14 days. For tropical pulmonary eosinophilia, a common regimen is 6 mg/kg/day divided three times daily for 14 days.
Completing the full course of treatment as prescribed by a healthcare provider is important, even if symptoms improve, to ensure parasite eradication and prevent recurrence. In some public health programs, a lower dose of 2 mg/kg for three days each month for 12 months may be used to interrupt filarial transmission. Dosage adjustments may be necessary for individuals with impaired renal function or sustained alkaline urine, as this can affect how the drug is processed and eliminated by the body.
Potential Side Effects and Warnings
Hetrazan can cause various side effects, often related to the body’s immune response to dying parasites. Common side effects include headache, fever, nausea, vomiting, dizziness, muscle or joint pain, skin rashes, itching, or asthma-like symptoms.
A more significant reaction, known as the Mazzotti reaction, can occur, especially in cases of onchocerciasis, though Hetrazan is less commonly used for this condition now. This reaction is characterized by a severe hypersensitivity response, potentially including rash, intense itching, headache, muscle and joint pain, rapid heartbeat, and low blood pressure. In rare instances, more serious effects like encephalitis or retinal hemorrhage have been reported.
Medical supervision is important to manage these reactions, and in severe infections, treatment may begin with lower doses or corticosteroids. Hetrazan is contraindicated in patients with known hypersensitivity to the drug, and generally during pregnancy, in infants, and in those with severe kidney or heart disease. It is important to inform a healthcare provider about all current medications, as diethylcarbamazine can have moderate interactions with numerous other drugs.