Antimalarials Pre Station

8/3/2019 Antimalarials Pre Station

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What is malaria?What is malaria?

Malaria is aMalaria is a parasitic infectionparasitic infection transmittedtransmitted

to humans through the bites of infectedto humans through the bites of infected

female mosquitoesfemale mosquitoes Once the female mosquitoes bite they injectOnce the female mosquitoes bite they inject

malariamalaria sporozoitessporozoites, which spread rapidly, which spread rapidly through the bloodstream and infect liver cells through the bloodstream and infect liver cells

These multiply and are rapidly releasedThese multiply and are rapidly released

from the infected liver cell«from the infected liver cell«



They emerge in the bloodstream in rapidThey emerge in the bloodstream in rapidquantities, invade and settle in thequantities, invade and settle in the red blood cellred blood cellss

T he Parasites multiply even more and T he Parasites multiply even more andemerge in bursts of new organismsemerge in bursts of new organisms

Due to the large numbers, theseDue to the large numbers, these

parasites can cause particularparasites can cause particulardamage to thedamage to the nervous system, liver,nervous system, liver,

and kidneyand kidney



There are four types of possible species of There are four types of possible species of

malaria which can infect humansmalaria which can infect humans ; ;

P. falciparumP. falciparumP. vivax,P. vivax,

P. malariaeP. malariae

P. ovale.P. ovale.

Majority of clinical cases are caused by Majority of clinical cases are caused by P. falciparumP. falciparum

andand P. vivaxP. vivax..



Did you know«Did you know«

Some parasites can rest in the liver forSome parasites can rest in the liver for

several months up to 4 yearsseveral months up to 4 years after aafter aperson is bitten by an infected mosquito!person is bitten by an infected mosquito!

When these parasites come out of When these parasites come out of hibernation and begin invading red bloodhibernation and begin invading red blood

cells, the person will become sickcells, the person will become sick



What areas are affected by What areas are affected by Malaria??Malaria??



Sub Saharan Africa

South and

Central America.

Southeast Asia

China, India,

Malaria is apparent in over 100 countriesand more than 40%

of the people in the world are at risk!!



What are the Symptoms of What are the Symptoms of

Malaria?Malaria?Malaria symptoms appear about 9 to 14 days after the infectiousMalaria symptoms appear about 9 to 14 days after the infectious

mosquito bite, although this varies with differentmosquito bite, although this varies with different Plasmodium Plasmodium

species.species.

Fever and fluFever and flu--like illnesslike illness

ShakingShaking

ChillsChills

HeadacheHeadache

Muscle achesMuscle aches

TirednessTiredness



Did you know«Did you know«

Infection withInfection with P. P. falciparumfalciparum is a medicalis a medical

Emergency requiring Hospitalization«Emergency requiring Hospitalization«

«if not promptly treated it may cause kidney failure,«if not promptly treated it may cause kidney failure,seizures, mental confusion, coma, and even Death!seizures, mental confusion, coma, and even Death!

Infection withInfection with P. vivaxP. vivax,, P. ovaleP. ovale can often becan often be

treated on an outpatient basis«treated on an outpatient basis«



Source: http://www.malariasite.com/malaria/ControlOfMalaria.htm



How do we treat Malaria??How do we treat Malaria??

Malaria can be treated with differentMalaria can be treated with differentspecific Antimalarial drugs«specific Antimalarial drugs«

«the antimalarial drugs available are««the antimalarial drugs available are«



QuinineQuinine

Quinine is a naturally occurringQuinine is a naturally occurringcompound, originally extracted fromcompound, originally extracted fromthe bark of South African Cinchonathe bark of South African Cinchona

tree.tree.

It was once the only drug available for theIt was once the only drug available for the

treatment of malaria, but has generally beentreatment of malaria, but has generally been

replaced by more effective and less toxicreplaced by more effective and less toxic

agents.agents. Treats the lifeTreats the life- -threateningthreatening

infections caused by Plasmodiuminfections caused by Plasmodium

falciparum malariafalciparum malaria

Administered in the form of tablets and capsules Administered in the form of tablets and capsules



Mode of ActionMode of Action

It is toxic to the malarial parasiteIt is toxic to the malarial parasite

It to interferes and disrupts the parasites ability toIt to interferes and disrupts the parasites ability tobreak down and digest hemoglobin.break down and digest hemoglobin.

By inhibiting heme polymerase, hence allowingBy inhibiting heme polymerase, hence allowingaccumulation of the cytotoxic substrate, heme.accumulation of the cytotoxic substrate, heme.

Results in the build up of toxic levels of the partially Results in the build up of toxic levels of the partially degraded haemoglobin in the parasite.degraded haemoglobin in the parasite.



ChloroquineChloroquine

This is the most common antimalarial drug but

there is increasing resistance to it

It is used to treat and prevent prophylaxis of malaria caused by Plasmodium vivax. P.ovale,

P.malariae.

Not recommended for the

treatment of falciparum malaria dueto widespread resistance



Mode of action- Blocks the enzymatic synthesis of DNA and RNA

- By forming a complex with DNA to prevents

replication or transcription to RNA

- The drug concentrates in vacuoles, raise the pH

- This interferes with its ability to metabolize

- Utilize erythrocyte hemoglobin



Stability: undergoes free radical oxidation

Protect chloroquine from sunlight, it can be stored in foil packaging

or in brown bottles



PrimaquinePrimaquine

Dosage forms:Dosage forms: TabletsTablets

Storage conditions:Storage conditions: RoomRoom

temperature and air tight container. temperature and air tight container.

Pr otect f r om light, heat and moisture.Pr otect f r om light, heat and moisture.

Primaquine is the essential coPrimaquine is the essential co- -drug with chloroquinedrug with chloroquinein treating all cases of malaria.in treating all cases of malaria.

It is highly effective against the gametocytes of allIt is highly effective against the gametocytes of all

plasmodia hence prevents spread of the disease to theplasmodia hence prevents spread of the disease to themosquito from the patient.mosquito from the patient.

It is also effective against the dormant tissue forms of It is also effective against the dormant tissue forms of P. vivaxP. vivax andand P. ovaleP. ovale malaria therefore offers radicalmalaria therefore offers radicalcure and prevents relapses.cure and prevents relapses.



Interferes with the mitochondria of theparasite and so without energy the parasite

dies. Parasites still persist in the liver and so

remaining parasites must be removed fromthe liver.

Primaquine is not used in the prevention of malaria, only in the treatment.

Mode of Action



Some other drugs are«Some other drugs are«

ProguanilProguanil (Paludrine) may be used as an(Paludrine) may be used as analternative to chloroquine in malarious areasalternative to chloroquine in malarious areaswhere there is no resistance to chloroquine.where there is no resistance to chloroquine.

DoxycyclineDoxycycline is an alternative to mefloquine oris an alternative to mefloquine orMalarone in areas where there are high levelsMalarone in areas where there are high levelsof chloroquine resistance.of chloroquine resistance.

MefloquineMefloquine is an effective antimalarial for areasis an effective antimalarial for areasof highly chloroquine resistant malaria.of highly chloroquine resistant malaria.Mefloquine is a prescription only drug and is notMefloquine is a prescription only drug and is not

suitable for everybody suitable for everybody



Common Side effectsCommon Side effects

NauseaNausea

VomitingVomiting Abdominal pain Abdominal pain

Upset stomachUpset stomach

Headache Visual disturbances

Intense itching



How can we minimize theHow can we minimize the

risk of malaria??risk of malaria?? ClothingClothing ²² Covering as much of theirCovering as much of their

body as possible may prevent bites.body as possible may prevent bites.

RepellentsRepellents ²² application of mosquitoapplication of mosquitorepellent to the skin will help inrepellent to the skin will help inpreventing bites outdoors.preventing bites outdoors.

Mosquito NetsMosquito Nets - - beds with mosquito netsbeds with mosquito netsmay prevent mosquito bitesmay prevent mosquito bites

Air Conditioning Air Conditioning ²²this reduces the amountthis reduces the amount

of mosquitoes present in the room.of mosquitoes present in the room.



ReferencesReferences

1.1. Website; Government factsWebsite; Government factshttp://www.doh.gov.za/facts/statshttp://www.doh.gov.za/facts/stats--notes/2003/malaria.htmlnotes/2003/malaria.html [accessed[accessed18 /04/07]18 /04/07]

2.2. Malaria Research Programme of theMalaria Research Programme of theMedical Research Council, South Africa;Medical Research Council, South Africa;http://www.malaria.org.zahttp://www.malaria.org.za..

[accessed18

/04/07][accessed18

/04/07]3.3. Malaria and Health;Malaria and Health;http://www.malariaandhealth.com/http://www.malariaandhealth.com/[accessed 18 /04/07][accessed 18 /04/07]

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