P: Antiparasitic products, insecticides and repellents
ATC group P holds drugs against parasites: antiprotozoals (P01), anthelmintics against worms (P02), and ectoparasiticides, insecticides and repellents (P03) [1]. Compared with viruses and bacteria, eukaryotic parasites have genomes and proteins that closely resemble those of their human hosts. Many anti-infective drugs act on host targets as well as on pathogen targets [2].
| Description | In plain terms | Example drug | |
|---|---|---|---|
| P01 | Antiprotozoals | kill single-celled parasites: malaria, amoebiasis, giardiasis | Artemether/lumefantrine (P01BF01) / metronidazole (P01AB01) |
| P02 | Anthelmintics | deworming drugs against parasitic worms | Albendazole (P02CA03) / praziquantel (P02BA01) |
| P03 | Ectoparasiticides, incl. scabicides, insecticides and repellents | kill skin parasites: scabies mites, lice; repellents | Permethrin (P03AC04) / diethyltoluamide, i.e. DEET (P03BX01) |
Dosing children
WHO treatment guidelines give children’s doses as weight bands, fixed dose steps by body weight. The bands differ between diseases, which complicates dosing a child treated for several diseases at once. A harmonized set of weight bands for tuberculosis, HIV, malaria and hepatitis C was judged feasible [3].
Infants are usually excluded from early dose-finding studies of antimalarials, so their doses are often extrapolated from older children or adults. Population PKPD modeling can support dose optimization from the sparse data that can be collected in infants [4]. For scaling clearance in children, allometric weight scaling with an exponent of 0.75 combined with a sigmoid maturation function has been proposed as a standard model, against which published models were compared [5].