Anti-Malarial Tablets for Kenya

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QUESTION

Which are the best tablets to take against malaria in Kenya?
Is there a malaria vaccination?

ANSWER

I’ll answer your second question first—no, there does not yet exist a commercially available malaria vaccine. Currently, one promising vaccine candidate is undergoing Phase 3 clinical trials in children in sub-Saharan Africa; recently published preliminary findings suggest that it provides roughly 50% protection against malaria.

As for which tablets you should take, there are a number of options, and choosing between them is basically a matter of personal preference. The three main kinds recommended for sub-Saharan Africa are doxycycline, atovaquone/proguanil combination (sold under the brand name Malarone) and mefloquine (sold as Lariam). These three differ in how you take them (usually once a day for doxycycline and Malarone and once a week for Lariam), how expensive they are (doxycycline is the cheapest, Malarone the most expensive) and the side effects you might experience (sun sensitivity is a big problem for some people on doxycycline, some people report hallucinations on Lariam, whereas Malarone usually has the fewest severe side effects).

If you’re not sure what’s best for you, you can always talk it over with your doctor when asking for the prescription, and they might have recommendations, based on their knowledge of your health and specific requirements.

It is worth noting that levels of chloroquine resistance are very high in sub-Saharan Africa, and so chloroquine is not recommended as a prophylactic when travelling to this region.

Malaria prophylaxis

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QUESTION:

What name brand medicine should you take if you are traveling to area where malaria is present?

ANSWER:

That depends on a few factors, such as where exactly you are going, whether you have had bad experiences with any malaria preventative drugs (prophylactics) in the past, and how much money you want to spend! Common brand names of malaria prophylactic drugs include Lariam (generic name mefloquine) and Malarone (a combination of atovaquone and proguanil). Doxycycline is also a popular antimalarial, which is often sold under its generic name.

G6PD and Malaria

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QUESTION:

Does one need to have a normal result in G6PD screening before he can take Malarial pills?

ANSWER:

In some cases, yes. When a patient has been diagnosed with Plasmodium ovale or Plasmodium vivax infection, in addition to medication such as chloroquine to target the blood stages of the parasite, an additional drug, called primaquine, may also be required. Primaquine kills the liver stages, known as hypnozoites, of these forms of malaria, preventing relapse of infection later on.

However, primaquine is known to cause severe haemolytic anaemia in people who are G6PD deficient. G6PD deficiency is restricted to certain populations or segments of populations; therefore it may be that not every person requiring primaquine will be tested for their G6PD status, only those considered high risk for potential deficiency. Patients with severe G6PD deficiency should not take primaquine; unfortunately at this stage there are no alternative drug regimens available. Patients with mild forms of G6PD deficiency should take primaquine at an alternative dose to G6PD-normal patients, usually 0.75mg/kg bodyweight once a week for 8 weeks (as opposed to 0.25mg/kg bodyweight once a day for 5 or 14 days, depending on the case history of the patient and the physician’s recommendation).

There is also some evidence that quinine can cause haemolysis in patients with G6PD deficiency; such patients may also have increased blood concentrations of mefloquine when taken concurrently with primaquine. As such, combinations of quinine or mefloquine with primaquine in G6PD-deficient patients is not recommended.

Causes of malaria, treatment with drugs and emerging resistance

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QUESTION:

What is malaria and what causes it besides bacteria? What is the name of the causal agent for malaria, which drug is used to cure it and how do the pathogens become resistant to the drugs?

ANSWER:

There are many questions in there! Malaria is actually caused by a single-celled animal, called a protozoan; it’s not a bacterial disease. There are different species of these protozoans, which form a genus called Plasmodium; the different species cause different types of malaria, for example Plasmodium falciparum, the most deadly and severe form, and Plasmodium vivax, which is widespread throughout the world but is a less acute infection. These different forms of malaria are each treated with different medications, depending on what is most effective and available; P. vivax, for example, can be treated with chloroquine, whereas in many places, P. falciparum has become resistant to this drug. In areas where resistance to chloroquine has emerged, other drugs are used; in Africa, artemisinin-based combination therapies (ACTs) are commonly used against chloroquine-resistant P. falciparum. Other drugs used to treat malaria include quinine compounds such as quinine sulphate, mefloquine, sulfadoxine-pyrimethamine and medications combining proguanil with atovaquone (marketed as Malarone).

The emergence of resistance to these drugs is a worrying phenomenon with respect to malaria; it is such a widespread and deadly disease, that the consequences of failed treatment are very high. Resistance can be caused by many factors, at the level of the drug, the human host, the mosquito host and also the malaria parasite itself. For example, poor drug compliance during treatment can lead to a failure to clear an infection completely, allowing the remaining parasites, which were less susceptible to the drug, to survive and reproduce. With successive generations, natural selection will lead to the evolution of strains of malaria parasites which are firmly resistant to that drug. The same process occurs when mass drug administration programmes, for example in areas of high malaria endemicity, give people sub-therapeutic doses of medication (in other words, doses of the drug that are too low to kill the parasite). Another problem is when people are not checked for their infection status after having been treated for malaria; if treatment fails for some reason, they will still have parasites in their blood, and should be treated again to ensure that all the malaria has been killed. If this doesn’t happen, the parasites can carry on reproducing, as in the processes described above. For these reasons, it is crucially important for people to be given accurate doses of medication, to ensure that they complete the full course of treatment, and that once treatment has been completed, they are accurately tested as negative for the malaria parasite. Finally, there are factors related to the affinity of the malaria parasite to its vector mosquito hosts which can lead to the emergence of drug resistant strains. For example, it has been shown that strains of malaria which are resistant to chloroquine are better able to survive and reproduce inside their mosquito hosts, leading to a greater population size of resistant parasites compared to drug-susceptible ones. It is for these reasons that malaria treatment and control programmes are now being very careful with the ways in which they administer drugs and monitor infections, in order to limit any further reisstance developing; similarly, pharmaceutical and biochemical researchers are constantly on the look-out for new compounds or methods of killing malaria parasites, which can be developed into new forms of treatment.

Lariam Legacy

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In 1990, Lariam (mefloquine) became the drug of choice for malaria prevention.  It was endorsed by the Centers for Disease Control (CDC) and prescribed for travelers, government workers, and the U.S. military who were going to regions where malaria was present. It was even given to airline crews who flew to malaria regions.

Mefloquine has been responsible for psychotic breakdowns, suicides and a host of other side effects.  Many people taking it stopped on their own because they were able to realize it was the drug that was causing the problems.

Here is a vignette of my experience with the drug after it was first released in 1990.

I was in charge of the health unit for a film being made in northern Thailand.  I was aware that there was chloroquine resistant malaria in that region.  I contacted the CDC and talked to the head of the Malaria Prevention Department. He told me that the drug of choice was Lariam. I was unable to obtain it in the USA but was able to get a supply in Europe.

I wrote a letter to the crew instructing them to take the drug while in Thailand. I  think now it was fortunate that many stopped taking the drug because they recognized it was causing “ weird” feelings. I myself took the drug and noticed no effects from it.  However about 3 weeks into the “shoot” a camera-crane operator went suddenly berserk.  It took 5 people to hold him down and get him to the hospital, where eventually enough valium calmed him down. He was however still paranoid and irrational, and had to be evacuated back to England.

I had, at the time, no idea what the cause was for his breakdown.  It wasn’t until two years later when reports started appearing about the drug’s side effects that I realized what the cause was.  I shuddered to think about some of the airline pilots and U.S. military who were being given the drug.

I would be interested to hear if anyone has had personal experiences, or friends who have experienced side-effects from the drug.

Malaria Prevention

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Photo by Matthew Naythons, MD

Malaria prevention consists of a combination of mosquito avoidance measures and chemoprophylaxis. Although very efficacious, none of the recommended interventions are 100% effective.

Mosquito Avoidance Measures

  • Because of the nocturnal feeding habits of Anopheles mosquitoes, malaria transmission occurs primarily between dusk and dawn.
  • Contact with mosquitoes can be reduced by remaining in well-screened areas, using mosquito bed nets (preferably insecticide-treated nets), using a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours, and wearing clothes that cover most of the body.
  • All travelers should use an effective mosquito repellent. [Read more…]

Malaria Treatment

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Malaria can be a severe, potentially fatal disease (especially when caused by Plasmodium falciparum) and treatment should be initiated as soon as possible.

Patients who have severe P. falciparum malaria or who cannot take oral medications should be given the treatment by continuous intravenous infusion.

Most drugs used in treatment are active against the parasite forms in the blood (the form that causes disease) and include:

  • chloroquine
  • atovaquone-proguanil (Malarone®)
  • artemether-lumefantrine (Coartem®)
  • mefloquine (Lariam®)
  • quinine
  • quinidine
  • doxycycline (used in combination with quinine)
  • clindamycin (used in combination with quinine)
  • artesunate (not licensed for use in the United States, but available through the CDC malaria hotline)

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.

How to treat a patient with malaria depends on:

  • The type (species) of the infecting parasite
  • The area where the infection was acquired and its drug-resistance status
  • The clinical status of the patient
  • Any accompanying illness or condition
  • Pregnancy
  • Drug allergies, or other medications taken by the patient

If you have or suspect you have malaria, you should contact your doctor immediately.

Source: Centers for Disease Control (CDC)