Makindo Medical Notes

🦠 Artemisinin-based combination therapies (ACTs) are the cornerstone of modern malaria treatment. It is vital that patients complete the full course to prevent resistance. Artemisinin was originally derived from the Chinese herb Artemisia annua (sweet wormwood), historically used to treat fevers — one of the great examples of traditional medicine informing modern pharmacology.

📘 About

• Always check the BNF entry here for current prescribing information and travel-specific malaria protocols.
• Artemether–lumefantrine is used for acute uncomplicated falciparum malaria and chloroquine-resistant non-falciparum malaria.
• Artesunate is preferred for severe or cerebral malaria and is available for IV administration.
• Both are derivatives of artemisinin — a natural endoperoxide compound with potent antimalarial activity.

⚗️ Pharmacology

• Artemether — lipid-soluble; administered orally or intramuscularly.
• Artesunate — water-soluble; given orally or intravenously for severe infection.
• Lumefantrine — a longer-acting partner drug that helps prevent recrudescence and resistance by clearing residual parasites.

⚙️ Mode of Action

• Exact mechanism is uncertain, but artemisinins act by producing reactive oxygen radicals after cleavage of their endoperoxide bridge within parasitic cells.
• These radicals damage parasite proteins and membranes, rapidly killing Plasmodium species (especially the trophozoite stage).
• Combination with lumefantrine provides both rapid parasite clearance and sustained suppression to prevent relapse.

💊 Dose Range (Take with Food)

Food (especially fat-containing meals) improves absorption of artemether–lumefantrine — essential for efficacy.

🔄 Interactions

• Drugs that prolong the QT interval (e.g. macrolides, fluoroquinolones, haloperidol, amiodarone) → ↑ arrhythmia risk.
• Use caution with other CYP3A4 substrates or inhibitors.
• See BNF for complete list of interactions.

⚠️ Cautions

• Perform ECG monitoring in patients with cardiac disease or co-administered QT-prolonging drugs.
• Take each dose with food to ensure adequate absorption.
• Use cautiously in hepatic impairment.
• Educate patients: complete the full course even if symptoms improve early — incomplete treatment fosters resistance.

🚫 Contraindications

• Known hypersensitivity to artemisinins or lumefantrine.
• Acute porphyria.
• Congenital or acquired QT prolongation or use of other QT-prolonging drugs.

💥 Adverse Effects

• Generally well tolerated; serious adverse events are uncommon.
• GI: abdominal pain, nausea, vomiting, diarrhoea, anorexia.
• CNS: dizziness, headache, insomnia, or fatigue.
• CV: QT prolongation (rare; monitor in at-risk patients).
• Transient rises in liver enzymes may occur.

🧠 Teaching Note

Artemisinin-based therapies revolutionised malaria treatment — they kill parasites faster than any other drug and reduce mortality dramatically. However, resistance is emerging in parts of Asia, so strict adherence and partner drugs like lumefantrine are critical to preserve efficacy. Always treat severe malaria with IV artesunate before switching to oral ACT once the patient can tolerate it.

📚 References

• Artemisinins in malaria treatment in the UK — BMJ Drug & Therapeutics Bulletin
• BNF: Artemether with Lumefantrine
• WHO Guidelines for Malaria, 2024 Update
• Public Health England: Imported Malaria Guidance (2023)