The Insight Corner Hub: Ridmal 40/320: Smart Antimalarial Therapy Using Dihydroartemisinin and Piperaquine

An Evidence-Based Overview for Clinical and Public Health Use

Introduction

Malaria remains one of the deadliest infectious diseases worldwide, especially across sub-Saharan Africa. To combat rising drug resistance and improve treatment outcomes, the World Health Organization (WHO) recommends artemisinin-based combination therapies (ACTs) for uncomplicated Plasmodium falciparum infections.

Ridmal 40/320, a fixed-dose combination of Dihydroartemisinin (DHA) 40 mg and Piperaquine (PQP) 320 mg, is one of the effective oral ACTs used in Rwanda and other malaria-endemic regions.

Formulation & Pharmacological Profile

Component	Strength per Tablet
Dihydroartemisinin (DHA)	40 mg
Piperaquine phosphate	320 mg

Dihydroartemisinin: A potent derivative of artemisinin, rapidly kills malaria parasites.
Piperaquine: A bisquinoline that sustains parasite clearance due to its long half-life.

Together, this combination ensures:

Fast parasitic clearance
Long post-treatment prophylaxis

Indications

Ridmal 40/320 is indicated for:

Treatment of uncomplicated malaria caused by P. falciparum.
Mixed Plasmodium infections (excluding severe malaria).

Dosage and Administration

Treatment with Ridmal 40/320 is once daily for 3 consecutive days (at 0, 24, and 48 hours). Dosage is weight-based.

Recommended Posology

Body Weight (kg)	Day 1 (0h)	Day 2 (24h)	Day 3 (48h)	Total Dose
13 – 24 kg	1 tablet	1 tablet	1 tablet	3 tablets
24 – 36 kg	2 tablets	2 tablets	2 tablets	6 tablets
36 – 75 kg	3 tablets	3 tablets	3 tablets	9 tablets
≥ 75 kg	4 tablets	4 tablets	4 tablets	12 tablets

📌 Notes:

Tablets must be taken with food to enhance absorption.
If the patient vomits within 30 minutes, the dose must be re-administered.
Doses are taken once per day, not multiple times daily.

Mechanism of Action

DHA: Generates reactive oxygen species that rapidly destroy parasite-infected red blood cells.
PQP: Inhibits detoxification of heme, resulting in parasite death, with a long-acting profile.

⚠️ Precautions & Contraindications

Avoid use in:

Patients with severe malaria (IV treatment is required).
Known QT prolongation or cardiac arrhythmia.
Allergy to artemisinin or piperaquine.
Children <13 kg.

Adverse Effects

Common	Uncommon
Headache, nausea	QT prolongation (rare)
Vomiting, abdominal pain	Dizziness, fatigue
Diarrhea	Palpitations (in predisposed)

Most side effects are mild and resolve spontaneously.

Use in Special Populations

Children: Safe for children ≥13 kg.
Pregnancy: Use with caution in 1st trimester; safer in 2nd and 3rd trimesters.
Lactation: Can be used; no contraindications reported.

Storage Conditions

Store below 30°C
Protect from moisture and sunlight
Keep out of reach of children

Clinical Advantages of Ridmal 40/320

Single daily dose for just 3 days
Easy weight-based dosing
High cure rates (>95%)
Offers post-treatment prophylaxis due to piperaquine's long half-life
Included in national treatment guidelines (e.g., Rwanda)

Infographic Summary Table

Patient Weight	Daily Dose	Total Tablets
13 – 24 kg	1 tablet	3 tablets
24 – 36 kg	2 tablets	6 tablets
36 – 75 kg	3 tablets	9 tablets
≥ 75 kg	4 tablets	12 tablets

Conclusion

Ridmal 40/320 is a smart, effective, and safe choice for managing uncomplicated malaria. Its fixed-dose formulation of DHA and PQP aligns with WHO treatment protocols and national malaria control programs. With once-daily dosing, high efficacy, and well-documented tolerability, it is ideal for broad clinical and public health use.

Clinicians and health educators should continue to promote proper usage and monitor for emerging resistance to maintain its long-term effectiveness.

📚 References

Rwanda FDA. Ridmal 40/320 Product Leaflet (2024).
WHO. Guidelines for the Treatment of Malaria – 3rd Edition.
ACTwatch Group. Trends in Artemisinin Combination Therapy Use (2023).
Medicines for Malaria Venture (MMV). Drug Profiles – Piperaquine & DHA.