Fighting filariasis

This week, we look at the drugs given for mass community treatment of filariasis ("Barawa" or "Yaanai kaachchal). You may have taken these two drugs in the last few months in the "National Plan for Elimination of Lymphatic Filariasis for Sri Lanka". The target of this programme is to reduce the worm load which leads to reduction of the transmission of the disease and with time eliminate Filariasis from Sri Lanka.

A person suffering from Lymphatic filariasis.

The drugs used are albendazole and diethylcarbamazine citrate (DEC). Albendazole is an intestinal anthelminthic, and DEC an antifilarial.

• The general principles in using medicinal drugs discussed previously apply here as well.
• Other uses: Apart from this preventive programme, these drugs are indicated in:
• Albendazole for treatment of worms
• Diethylcarbamazine citrate for treatment of filarial infection (e.g.; acute lymphangitis, lymphoedema, elephantiasis, tropical pulmonary eosinophelia). In these instances your doctor may prescribe a longer course of DEC (7-14 days)
• Allergy: Both drugs can cause allergic reactions, but it is more of a problem with DEC. The risk of allergy is high when a person has a large load of filarial worms as the allergic reactions are induced by disintegrating worms.

The symptoms may occur in a few hours after taking DEC, and generally do not last for more than three days. Symptoms include fever, headache, aches and pains, joint pain, dizziness, malaise, vomiting, urticaria, cough and sometimes attacks of wheezing. Consult your doctor before taking these drugs if you are allergic to any drugs or substances such as foods, preservatives or dye.

If you develop the symptoms mentioned above, or any other unusual events after taking DEC, please seek medical advice.

• Pregnancy and breast feeding: Pregnant women and breast feeding mothers are not included in the mass community treatment programmes. Albendazole is associated with foetal malformations in animals, and the manufacturers inform that there are no adequate and well controlled trials in human pregnancy. Albendazole is therefore usually contra-indicated during pregnancy. The manufacturer also cautions against becoming pregnant while taking albendazole or within one month of completing treatment.
• Children: Children under the age of two years are normally excluded in the mass community treatment programme. An important practical difficulty in giving albendazole to young children is the size of the tablet as there are no liquid preparations. Hence children as young as two years have to swallow these tablets. Albendazole is a relatively large tablet. There is always a risk of choking when these drugs are given unbroken to children. Parents have to make sure that they crush the tablets and give them as powder to young children.
• Drug interactions: Though there are no documented drug interactions with these drugs, it is preferable to seek advice from your doctor if you are taking some other drugs (including over the counter preparations, cough medicines, herbal remedies, nutraceuticals).
• Other medical conditions: Elderly and debilitated patients especially those with cardiac and renal failure are excluded from mass community treatment programmes.

Precautions

• Drowsiness and dizziness: Some people can get dizzy or drowsy or both due to DEC. Avoid driving and operating machines if you have this side effect of the drug.
• Patients with allergic tendency: Seek medical advice before you take DEC (see above).
• Side effects: Along with its beneficial effects, any medicine may cause some unwanted side effects. These drugs are not exceptions.
• Albendazole: Headache, stomach upsets, diarrhoea, abdominal pain, allergic reactions
• Diethylcarbamazine citrate: Headache, drowsiness, dizziness, abdominal pain, nausea, vomiting, lethargy, loss of appetite (most of these reactions begin within 1 to 2 hours of taking DEC, and persist for a few hours) allergic reactions (see above), reversible proteinuria (passing protein in urine).
• Local reactions: Nodules (due to dead adult worms) may appear in the groin area.

Other side effects not listed above may also occur in some patients. If you have noticed any other unwanted effects when taking these drugs, inform Info Vig.

Info-Vig, Department of Pharmacology (PO Box 271, Kynsey Road, Colombo 8 - TP Number 5677244) monitors adverse drug reactions (side effects). Reporting suspected adverse drug reaction to Info -Vig will help in monitoring the drug safety in Sri Lanka.

Information provided by Dr. Shalini Sri Ranganathan, Senior Lecturer and Professor Rohini Fernandopulle, Department of Pharmacology, University of Colombo.