A 28-year-old male labourer from West Bengal presents with fever, chills, and sweating for 3 days. He reports the fever occurs every 48 hours with a pattern of cold stage (30 min), hot stage (4–5 hours), and sweating stage (2–3 hours). Thick and thin blood smears show ring forms and Schüffner's stippling. Haemoglobin is 9.2 g/dL and platelets are 95,000/μL. What is the most appropriate first-line antimalarial drug according to NVBDCP guidelines?

Explanation

## Plasmodium vivax Malaria — NVBDCP-Recommended Treatment This patient has **uncomplicated P. vivax malaria** with: - Tertian fever pattern (48-hour cycle) - Schüffner's stippling (pathognomonic for P. vivax) - Ring forms on blood smear - Mild anaemia and thrombocytopenia (uncomplicated) - No signs of severe malaria (no altered sensorium, renal failure, severe anaemia, or pulmonary oedema) ### NVBDCP Treatment Algorithm for P. vivax **Key Point:** NVBDCP (National Vector Borne Disease Control Programme) recommends **chloroquine as first-line** for uncomplicated P. vivax malaria in India, despite emerging chloroquine resistance in some endemic areas. Artemisinin-based combination therapy (ACT) is reserved for **severe malaria or ACT-suspected resistance zones**. **High-Yield:** Standard chloroquine dosing for P. vivax: | Dose | Timing | Total Base | | --- | --- | --- | | 600 mg base | Stat (Day 1, 0 hrs) | 600 mg | | 300 mg base | Day 1, 6 hrs | 300 mg | | 300 mg base | Day 2, 24 hrs | 300 mg | | 300 mg base | Day 3, 48 hrs | 300 mg | | **Total** | **3 days** | **1500 mg base** | **Clinical Pearl:** After chloroquine, **primaquine 0.25 mg/kg/day for 14 days** is mandatory for P. vivax (and P. ovale) to eliminate hypnozoites and prevent relapse. G6PD testing should be done before primaquine to avoid haemolysis. **Warning:** Do NOT confuse P. vivax with P. falciparum. P. falciparum requires **ACT (artemether + lumefantrine, artesunate + amodiaquine, or dihydroartemisinin + piperaquine)** as first-line, especially in high-transmission zones. This patient's Schüffner's stippling and 48-hour cycle confirm P. vivax, not falciparum. ### Why NOT the Other Agents? **Artemether (Option B):** Reserved for **severe malaria** (cerebral malaria, severe anaemia, renal failure, pulmonary oedema, shock). This patient has uncomplicated malaria with normal mental status and haemodynamic stability. **Quinine (Option C):** Second-line IV agent for severe malaria or when oral therapy is not tolerated. Not indicated for uncomplicated malaria. **Atovaquone–Proguanil (Option D):** Effective for P. falciparum and P. vivax but is **expensive, not part of NVBDCP guidelines**, and reserved for travellers or drug-resistant cases. **Mnemonic — P. vivax Treatment: CLIP** - **C**hloroquine (first-line for uncomplicated) - **L**ong-acting (primaquine for hypnozoites) - **I**ntramuscular artemether (if severe) - **P**rimaquine mandatory (14 days, post-G6PD test) ```mermaid flowchart TD A[Suspected Malaria]:::outcome --> B{Severity?}:::decision B -->|Uncomplicated| C{Species?}:::decision B -->|Severe| D[Artemether IM]:::action C -->|P. vivax/ovale| E[Chloroquine 1500 mg base over 3 days]:::action C -->|P. falciparum/mixed| F[ACT artemether + lumefantrine]:::action E --> G[Primaquine 0.25 mg/kg/day × 14 days]:::action F --> H[Monitor for resistance]:::action G --> I[Check G6PD before primaquine]:::action D --> J[Switch to oral ACT when able]:::action ``` [cite:Park 26e Ch 7 (NVBDCP); Harrison 21e Ch 218]