A fixed-dose combination of an anthelmintic (Diethylcarbamazine) and a first-generation antihistamine (Chlorpheniramine Maleate). Primarily used in the Indian context for the treatment and prophylaxis of lymphatic filariasis (caused by Wuchereria bancrofti and Brugia malayi) and tropical pulmonary eosinophilia. The combination leverages the anti-filarial action of DEC with the anti-allergic properties of Chlorpheniramine to mitigate the allergic and inflammatory reactions (Mazzotti-type reactions) commonly triggered by the rapid death of microfilariae.
Adult: For Filariasis: 6 mg/kg body weight per day, divided into three doses, after meals for 12 days. Often administered as 1 tablet (250mg DEC + 4mg CPM) three times a day for an average adult (50-60 kg). For Mass Drug Administration (MDA) programs: A single annual dose of 6 mg/kg (e.g., 2 tablets stat for an adult).
Note: Administer after food to minimize gastrointestinal upset. Tablets should be swallowed whole with a full glass of water. For the full 12-day treatment course, adherence is critical for efficacy. In MDA programs, the dose is directly observed.
Diethylcarbamazine citrate (DEC) immobilizes microfilariae by altering their surface membranes, making them susceptible to host phagocytosis by the reticuloendothelial system. It also damages adult worms, impairing their muscular activity and metabolism. Its exact molecular target is not fully elucidated but may involve arachidonic acid metabolism. Chlorpheniramine Maleate is a competitive reversible antagonist of histamine at the H1 receptor, thereby mitigating the allergic symptoms (pruritus, rash, fever, bronchospasm) caused by the release of antigens from dying parasites.
Pregnancy: Category C (US FDA). DEC crosses placenta. Use only if potential benefit justifies potential fetal risk. Avoid in first trimester unless absolutely necessary. Data from Indian studies in MDA programs suggest it may be used in the 2nd/3rd trimester in endemic areas after risk-benefit assessment.
Driving: NOT ADVISABLE. Chlorpheniramine causes significant drowsiness and impairs alertness and motor coordination. Patients should not drive or operate heavy machinery until their individual response is known.
| CNS Depressants (Alcohol, Benzodiazepines, Opioids) | Additive sedation and impaired psychomotor performance. | Major |
| Monoamine Oxidase Inhibitors (MAOIs) e.g., Phenelzine | Potentiation of anticholinergic and CNS effects of Chlorpheniramine; hypertensive crisis risk. | Contraindicated |
| Other Anticholinergics (Atropine, Tricyclic Antidepressants) | Increased risk of anticholinergic side effects (dry mouth, urinary retention, confusion). | Major |
| Hepatic Enzyme Inducers (Phenobarbital, Rifampicin) | May increase metabolism of Chlorpheniramine, reducing its efficacy. | Moderate |
| Hepatic Enzyme Inhibitors (Cimetidine, Ketoconazole) | May increase plasma levels of Chlorpheniramine, increasing sedation risk. | Moderate |
Same composition (Diethylcarbamazine (250mg) + Chlorpheniramine Maleate (4mg)), different brands: