Malaria prophylaxis

Question 1

Questions to ask regarding travel details?

Answer 1

1. Go where? Which part of country you going?
2. Go how long? When you come back?
3. What you do there? Any outdoor activities?

Question 2

A doctor asks for your advice on how to give doxycycline antimalarial prophylaxis to give to an 25 yo male with NKDA and comorbidities. He is going to Kenya *(high-resistance to chloroquine) flying in 3 days time, and will be back three weeks later)

Answer 2

PO doxycycline 100 mg OD
- Start 1-2 days prior to departure
- Continue for another 4 weeks after departure

Question 3

How long to avoid pregnancy after finishing a course of mefloquine?

Answer 3

3 months

Question 4

Can Malarone (atovaquone-proguanil) be used in a 75yo female patient whose CrCL = 29?

Answer 4

No. Malarone contraindicated in CrCL < 30 mL/min

Question 5

Describe the regimen for mefloquine in malarial prophylaxis

Answer 5

250 mg once weekly
- Start 1 - 2 weeks before departure (ideally 3 weeks)
- Continue for 4 weeks after return

Question 6

Main concern or side effect of mefloquine

Answer 6

Neuropsychiatric adverse effects

Question 7

Which of the following malarial prophylaxis agent should be avoided in patients with G6PD?
a) Mefloquine
b) Doxycycline
c) Chloroquine
d) Malarone
e) None of the above

Answer 7

Answer: C (Chloroquine)

Question 8

How long to avoid pregnancy after completing a course of doxycycline for malaria prophylaxis?

Answer 8

1 week

Question 9

What is the preferred malaria prophylactic agent for pregnancy?

Answer 9

Chloroquine (can be used in all trimester of pregnancy)

Question 10

Describe the course of Malarone for malaria prophylaxis

Answer 10

One tablet (250/150 mg A-P) once a day
- Start 1-2 days before departure
- Continue for 7 days after return

Question 11

Describe the course of chloroquine for malaria prophyalxis

Answer 11

Two 150 mg base (equivalent to 250 mg chloroquine phosphate) weekly
- Start one week before departure
- Continue for 4 weeks after return

Question 12

Can mefloquine be used in patients who are flying off at a short notice? If yes, describe the regimen and state the disadvantage

Answer 12

Yes
- 250 mg x 3 days before departure as loading dose
- Weekly after that
Disadvantage: more side effects

Question 13

Dose of mefloquine for a 5 yo child who weighs 25 kg?

Answer 13

125 mg once weekly

Question 14

Dose of mefloquine for a 10yo child who weighs 46 kg?

Answer 14

250 mg once weekly

Question 15

Dose of mefloquine for a 2yo child who weighs 8 kg?

Answer 15

4.6 mg/kg, hence about 40 mg once weekly
(< 9kg are dosed by weight, else in incrementals of 62.5 mg)

Question 16

Anti-malarial drug that interacts with oral contraceptives

Answer 16

Doxycycline. May require other forms of birth control

Question 17

If a patient who just took mefloquine 15 minutes ago vomited, what should he or she be instructed to do?

Answer 17

Take another dose of mefloquine (cutoff time for this is 30 mintues). If vomiting persists, visit a doctor immediately

Question 18

If a patient who just took malarone 50 minutes ago vomited, what should he or she be instructed to do?

Answer 18

Take another dose of malarone (cutoff time for this is 60 mintues). If vomiting persists, visit a doctor immediately

Question 19

Significant side-effects that should be counselled and monitored in patients taking chloroquine?

Answer 19

1. Blurred vision (retinopathy)
2. Muscle weakness and cramps

Question 20

A patient taking chloroquine is also taking antacid. What is the counselling point for this patient?

Answer 20

Space them at least 4 hours apart

Question 21

What can you tell a patient to improve the absorption of malarone?

Answer 21

Take with milk

Question 22

How long should patients monitor for signs and symptoms of malaria after travelling to a malaria-prevalent country?

Answer 22

1 year

Question 23

In patients with epilepsy, what are the anti-malarial drugs to avoid?

Answer 23

Chloroquine and mefloquine

Question 24

What antiepileptic drugs do doxycycline interact with, and hence not recommended to be used together? What is the interaction?

Answer 24

1. Carbamazepine
2. Phenytoin
   - both decreases doxycycline levels by increasing its metabolism

Question 25

Anti-malarial drugs that are preferred in patients with renal insufficiency

Answer 25

Mefloquine and doxycycline

Question 26

Anti-malarial drug that is safe in lactating patients

Answer 26

Mefloquine