Antimalarials

Question 1

What is the short course of treatment to kill gametocytes for Plasmodium vivax and ovale?

Answer 1

Radical cure will kill gametocytes as well

This treatment is essential for preventing transmission.

Question 2

What are the adverse effects of artesunate?

Answer 2

• Similar to artemether
• Dose-dependent haemolysis even weeks after treatment

Cautions include renal and hepatic failure, and children with anaemia.

Question 3

List the cautions for the use of artemether.

Answer 3

• Renal failure
• Chronic cardiac disease patients
• Meningitis

Higher concentration of artemether is documented in CSF.

Question 4

What is the elimination half-life of artemether?

Answer 4

7 hours

Artemether shows auto-induction.

Question 5

What are the indications for IV or IM artesunate?

Answer 5

• Initial treatment of severe malaria
• Pre-referral treatment of severe malaria
• FDC with other AMM for uncomplicated malaria

Artesunate is crucial for severe cases.

Question 6

What is the fixed drug combination (FDC) of artemether?

Answer 6

Artemether-Lumefantrine

Used for treatment of uncomplicated malaria caused by Plasmodium falciparum and vivax.

Question 7

What is the mode of action of artemisinin derivatives?

Answer 7

• Converted to dihydroartemisinin in the liver
• Responsible for most antimalarial action
• Rapidly effective against blood stages of the parasite

Involves cation-mediated generation of reactive intermediates.

Question 8

True or false: Artemisinin derivatives are effective against sporozoites and extra erythrocytic stages.

Answer 8

FALSE

They are inactive against sporozoites and liver stages.

Question 9

What are the safety considerations for artemisinin derivatives during pregnancy?

Answer 9

• Avoid for uncomplicated malaria in T1
• IV artesunate can be given for severe malaria
• Can be given in T2, T3, and lactation

Benefits outweigh risks for severe cases.

Question 10

What are the adverse effects of chloroquine?

Answer 10

• GIT symptoms
• Headache
• Blurred vision
• Pruritus
• Dizziness
• Hypotension

High doses can lead to more severe effects.

Question 11

What is the pharmacokinetics of chloroquine?

Answer 11

• Well absorbed
• Concentrated in parasitized red cells
• Long half-life of about 7 days

30% metabolized, 70% excreted unchanged in urine.

Question 12

What is the mode of action of chloroquine?

Answer 12

• Concentrates within parasitized RBC
• Prevents digestion of haemoglobin by the parasite

Also forms complexes with parasite DNA.

Question 13

What is the indication for primaquine?

Answer 13

Radical cure for Plasmodium vivax and ovale

It is contraindicated in pregnancy and lactation.

Question 14

What is the recommended treatment for uncomplicated P. falciparum malaria in the first trimester of pregnancy?

Answer 14

Oral quinine sulfate plus clindamycin

Dosage is 10mg/kg at 8-hour intervals for 7 days.

Question 15

What is the primary objective of malaria treatment?

Answer 15

Rapid and complete elimination of Plasmodium parasite

Prevents progression to severe disease or death.

Question 16

What are the types of chemoprophylaxis mentioned?

Answer 16

• Intermittent preventive treatment in pregnancy
• Intermittent preventive treatment in infants
• Seasonal malaria chemoprevention

Travelers to endemic areas should start prophylactics before entering.

Question 17

What is the contraindication for primaquine?

Answer 17

Pregnancy, lactation, and infants under 1 year

Special considerations for G6PD deficiency patients.

Question 18

What is the recommended treatment for pregnant or breastfeeding women when Primaquine is contraindicated?

Answer 18

• Weekly Chloroquine (chemoprophylaxis) until pregnancy and breastfeeding is completed
• After that, depending on G6PD status, treat with primaquine to prevent future relapses

Infants: No data available about safety of primaquine. WHO suggests giving primaquine at 6-12 months of age.

Question 19

What is the course duration for Primaquine in radical cure?

Answer 19

2 weeks course at the end of acute treatment

Eliminates the dormant hepatic hypnozoites, preventing relapse.

Question 20

What are the adverse effects of Quinine?

Answer 20

• Hypoglycaemia
• Hypotension
• Arrhythmias (monitor blood glucose and cardiac monitoring)

Quinine is used when IV Artesunate is not available for severe Plasmodium falciparum malaria.

Question 21

What is the total dose of Chloroquine for mono-infection with Plasmodium vivax?

Answer 21

• 25 mg/kg over three days: 10 mg/kg on D1 and D2, 5 mg/kg on D3
• Followed by Primaquine 15 mg base/day for 14 days

PQ is contraindicated in pregnancy, lactation, infants, and severe G6PD deficiency.

Question 22

What does radical cure refer to in the context of malaria treatment?

Answer 22

Eradication of persistent hepatic forms (hypnozoites) in Plasmodium vivax and ovale

Follows after treating the acute attack.

Question 23

What is the mode of administration for Chloroquine?

Answer 23

Usually given orally

Immediate side effects can be managed by taking the tablets with meals, correcting dehydration, and reducing fever.

Question 24

What is the mode of action of Primaquine?

Answer 24

Not well understood; possibly interferes with mitochondrial function

Well absorbed and moderately concentrated in tissues.

Question 25

Define the term **sporontocidal**.

Answer 25

Destroys the sporozoites ## Footnote Important for understanding the life cycle of malaria parasites.

Question 26

Define the term **blood schizonticide**.

Answer 26

Destroys asexual parasites in blood ## Footnote Different anti-malarial medicines act at various stages in the life cycle of the parasite.

Question 27

What are the **commonly used anti-malarial medicines (AMM)**?

Answer 27

* Artemisinin based combination therapy (ACT) * Primaquine (PG) * Chloroquine (CQ) * Quinine (Q) * Artesunate (A) ## Footnote Refer to WHO for a complete list.

Question 28

What is the **indication** for **Primaquine**?

Answer 28

* Radical cure (PV or PO) * Prevention of transmission (Pf) ## Footnote Almost invariably used with another drug, usually ACT as per current guidelines.

Question 29

What are the **side effects** of **Quinine**?

Answer 29

* GIT side effects: nausea, vomiting, gastric irritation, diarrhea, abdominal pain, anorexia * Idiosyncratic reactions: urticaria, asthma, edema of eyelids, thrombocytopenia, fever ## Footnote Quinine toxicity can lead to severe conditions like black water fever.

Question 30

What is the definition of **treatment failure** in malaria?

Answer 30

Inability to clear malarial parasitaemia or prevent recrudescence after administration of an antimalarial medicine ## Footnote Factors contributing include incorrect dosage, poor patient compliance, and drug resistance.

Question 31

What is the definition of **antimalarial resistance**?

Answer 31

Ability of a parasite strain to survive and/or multiply despite the administration and absorption of a drug given in doses equal to or higher than those usually recommended ## Footnote Multidrug resistance (MDR) is defined as resistance to more than two antimalarial compounds of different chemical classes.

Question 32

What are the **facilitators** of the emergence of **antimalarial resistance**?

Answer 32

* Parasite mutation rate * Overall parasite load * Strength of drug selected * Poor patient compliance * Poor adherence to malaria treatment guidelines * Improper dosing, timing, storage * Fake drugs leading to inadequate drug exposure ## Footnote Poor-quality antimalarials can lead to treatment failure.