a drug of choice in the treatment of filari-asis, loiasis, and tropical
eosinophilia. It has been replaced by ivermectin for the treatment of
a synthetic piperazine derivative, is marketed as a citrate salt. It is rapidly
absorbed from the gastrointestinaltract; after a 0.5 mg/kg dose, peak plasma
levels are reached within 1–2 hours. The plasma half-life is 2–3 hours in the
presence of acidic urine but about 10 hours if the urine is alkaline, a
Henderson-Hasselbalch trapping effect . The drug rapidly equilibrates with all
tissues except fat. It is excreted, prin-cipally in the urine, as unchanged
drug and the N-oxide metabo-lite. Dosage may have to be reduced in patients
with persistent urinary alkalosis or renal impairment.
immobilizes microfilariae and alters their surface structure, displacing them
from tissues and making them more susceptible to destruction by host defense
mechanisms. The mode of action against adult worms is unknown.
The drug should be
taken after meals.
is the drug of choice for treatment of infections with these parasites because
of its efficacy and lack of serious toxicity. Microfilariae of all species are
rapidly killed; adult parasites are killed more slowly, often requiring several
courses of treatment. The drug is highly effective against adult L loa. The extent to which W bancrofti and B malayi adults are killed is not known, but after appropriate
therapy microfilariae do not reappear in the majority of patients.
These infections are
treated for 2 or (for L loa) 3 weeks,
with initial low doses to reduce the incidence of allergic reactions to dying
microfilariae. This regimen is 50 mg (1 mg/kg in children) on day 1, three 50
mg doses on day 2, three 100 mg doses (2 mg/kg in children) on day 3, and then
2 mg/kg three times daily to complete the 2–3 week course.
Antihistamines may be
given for the first few days of therapy to limit allergic reactions, and
corticosteroids should be started and doses of diethylcarbamazine lowered or
interrupted if severe reactions occur. Cures may require several courses of
treatment. For patients with high L loa
worm burdens (more than 2500 cir-culating parasites/mL), strategies to decrease
risks of severe toxicity include apheresis, if available, to remove
microfilariae before treat-ment with diethylcarbamazine or therapy with
albendazole, which is slower acting and better tolerated, before therapy with
diethyl-carbamazine or ivermectin.
may also be used for chemoprophylaxis (300 mg weekly or 300 mg on 3 successive
days each month for loiasis; 50 mg monthly for bancroftian and Malayan
eosinophilia, diethylcarbamazine is given orally at a dosage of 2 mg/kg three
times daily for 7 days. Diethylcarbamazine is effective in Mansonella streptocerca infections, since it kills both adults and
microfilariae. Limited information suggests that the drug is not effective,
however, against adult M ozzardi or M per-stans and that it has limited
activity against microfilariae of theseparasites. An important application of
diethylcarbamazine has been mass treatment to reduce the prevalence of W bancrofti infec-tion, generally in
combination with ivermectin or albendazole.This strategy has led to excellent
progress in disease control in a number of countries.
diethylcarbamazine, which are generally mild and transient, include headache,
malaise, anorexia, weakness, nausea, vomiting, and dizziness. Adverse effects
also occur as a result of the release of proteins from dying microfilariae or
adult worms. Reactions are particularly severe with onchocerciasis, but
diethyl-carbamazine is no longer commonly used for this infection, because
ivermectin is equally efficacious and less toxic. Reactions to dying
microfilariae are usually mild in W
bancrofti, more intense in B malayi,
and occasionally severe in L loa
infections. Reactions include fever, malaise, papular rash, headache,
gastroin-testinal symptoms, cough, chest pain, and muscle or joint pain.
Leukocytosis is common. Eosinophilia may increase with treat-ment. Proteinuria
may also occur. Symptoms are most likely to occur in patients with heavy loads
of microfilariae. Retinal hemor-rhages and, rarely, encephalopathy have been
the third and twelfth days of treatment, local reactions may occur in the
vicinity of dying adult or immature worms. These include lymphangitis with
localized swellings in W bancrofti
and B malayi, small wheals in the
skin in L loa, and flat papules in M streptocerca infections. Patients with
attacks of lymphangitis dueto W bancrofti
or B malayi should be treated during
a quiescent period between attacks.Caution is advised when using diethylcarbamazine in patients
with hypertension or renal disease.