A 28-year-old Nigerian man living in London presents with a 2-day history of fever, headache, and vomiting. He visited Lagos 2 weeks ago and took no prophylaxis. A rapid diagnostic test (RDT) is positive for P. falciparum histidine-rich protein 2 (HRP2). His parasitaemia on thin film is 1.5%. He is alert, able to tolerate oral medication, has no features of severe malaria, haemoglobin 11.8 g/dL, creatinine 92 µmol/L, and glucose 5.4 mmol/L. What is the most appropriate treatment?