Background: Foreign migrant workers with work permits in Thailand are given once a year 300 mg diethylcarbamazine (DEC) for bancroftian filariasis, and 400 mg albendazole (ABZ) for helminthiasis. Treatment effectiveness, tolerability, and safety of two treatment arms, DEC + ABZ and DEC alone, had never been fully documented.

Objective: Evaluate the tolerability of the two treatment arms and analyze the effects of adverse reaction, prevalence, and intensity of both common and uncommon adverse drug reactions (ADR) in relation to the reaction time (2 hours = acute, >2 to 24 hours = subacute, and >24 to 72 hours = latent).

Material and Method: A hospital-based clinical study of on-hour-2 treatment with both treatment arms in 280 Myanmar male migrant volunteers (DEC + ABZ = 150, DEC = 130) was conducted in Phang Nga province, southern Thailand. Of these, ADR evaluation at three reaction times was performed using antigenemic (WbAg+) and non-antigenemic (WbAg-) volunteer groups (DEC + ABZ/WbAg+ = 14, DEC/WbAg+ = 12, DEC + ABZ/WbAg- = 8, and DEC/WbAg- = 16).

Results: Both drug groups had similarly overall ADR prevalence [5.2% for DEC + ABZ and 5.1% for DEC (p>0.05)], as well as mean ADR_acute scores (p>0.05) on hour 2 post-treatment. The four groups had maximum overall prevalence (10% to 40% for ADR_subacute). It was more likely to show no relationship between treatment arms and WbAg (neither WbAg+ nor WbAg-) with adverse reaction intensity for ADR_acute, ADR_subacute, or ADR_latent. Three major specific ADR were fatigue, dizziness, and headache.

Conclusion: Adverse reaction prevalence and intensity were independent for WbAg and treatment arm. The DEC + ABZ have no greater effects on ADR development as the DEC does. The common ADR after treatment are not required for symptomatic treatment. The study confirms DEC + ABZ regime can be safe and not toxic for use in mass treatment of those migrants in Thailand and, its value, in a mass annual single dose treatment, is beneficial for the Global Alliance to Eliminate of Lymphatic Filariasis (GAELF).

Keywords: Diethylcarbamazine, Albendazole, Adverse drug reactions, Myanmar migrants