Antimalarial medications or simply antimalarials are a type of antiparasitic chemical agent, often naturally derived, that can be used to treat or to prevent malaria, in the latter case, most often aiming at two susceptible target groups, young children and pregnant women. As of 2018, modern treatments, including for severe malaria, continued to depend on therapies deriving historically from quinine and artesunate, both parenteral (injectable) drugs, expanding from there into the many classes of available modern drugs. Incidence and distribution of the disease is expected to remain high, globally, for many years to come; moreover, known antimalarial drugs have repeatedly been observed to elicit resistance in the malaria parasite—including for combination therapies featuring artemisinin, a drug of last resort, where resistance has now been observed in Southeast Asia. As such, the needs for new antimalarial agents and new strategies of treatment remain important priorities in tropical medicine. As well, despite very positive outcomes from many modern treatments, serious side effects can impact some individuals taking standard doses.
Digitoxin is a cardiac glycoside used for the treatment of heart failure and certain kinds of heart arrhythmia. It is a phytosteroid and is similar in structure and effects to digoxin, though the effects are longer-lasting. Unlike digoxin, which is eliminated from the body via the kidneys, it is eliminated via the liver, and so can be used in patients with poor or erratic kidney function. While several controlled trials have shown digoxin to be effective in a proportion of patients treated for heart failure, the evidence base for digitoxin is not as strong, although it is presumed to be similarly effective.
Amiodarone is an antiarrhythmic medication used to treat and prevent a number of types of cardiac dysrhythmias. This includes ventricular tachycardia (VT), ventricular fibrillation (VF), and wide complex tachycardia, as well as atrial fibrillation and paroxysmal supraventricular tachycardia. Evidence in cardiac arrest, however, is poor. It can be given by mouth, intravenously, or intraosseously. When used by mouth, it can take a few weeks for effects to begin.
Cytochrome P450 3A4 is an important enzyme in the body, mainly found in the liver and in the intestine, which in humans is encoded by CYP3A4 gene. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from the body. It is highly homologous to CYP3A5, another important CYP3A enzyme.
Zafirlukast is an orally administered leukotriene receptor antagonist (LTRA) used for the chronic treatment of asthma. While zafirlukast is generally well tolerated, headache and stomach upset often occur. Some rare side effects can occur, which can be life-threatening, such as liver failure. Churg-Strauss syndrome has been associated with zafirlukast, but the relationship isn't thought to be causative in nature. Overdoses of zafirlukast tend to be self-limiting.
In pharmaceutical sciences, drug interactions occur when a drug's mechanism of action is affected by the concomitant administration of substances such as foods, beverages, or other drugs. A popular example of drug-food interaction is the effect of grapefruit in the metabolism of drugs.
Artemether is a medication used for the treatment of malaria. The injectable form is specifically used for severe malaria rather than quinine. In adults, it may not be as effective as artesunate. It is given by injection in a muscle. It is also available by mouth in combination with lumefantrine, known as artemether/lumefantrine.
Chloroquine is a medication primarily used to prevent and treat malaria in areas where malaria remains sensitive to its effects. Certain types of malaria, resistant strains, and complicated cases typically require different or additional medication. Chloroquine is also occasionally used for amebiasis that is occurring outside the intestines, rheumatoid arthritis, and lupus erythematosus. While it has not been formally studied in pregnancy, it appears safe. It was studied to treat COVID-19 early in the pandemic, but these studies were largely halted in the summer of 2020, and the NIH does not recommend its use for this purpose. It is taken by mouth.
Primaquine is a medication used to treat and prevent malaria and to treat Pneumocystis pneumonia. Specifically it is used for malaria due to Plasmodium vivax and Plasmodium ovale along with other medications and for prevention if other options cannot be used. It is an alternative treatment for Pneumocystis pneumonia together with clindamycin. It is taken by mouth.
Anthracyclines are a class of drugs used in cancer chemotherapy that are extracted from Streptomyces bacterium. These compounds are used to treat many cancers, including leukemias, lymphomas, breast, stomach, uterine, ovarian, bladder cancer, and lung cancers. The first anthracycline discovered was daunorubicin, which is produced naturally by Streptomyces peucetius, a species of Actinomycetota. Clinically the most important anthracyclines are doxorubicin, daunorubicin, epirubicin and idarubicin.
Hydroxychloroquine, sold under the brand name Plaquenil among others, is a medication used to prevent and treat malaria in areas where malaria remains sensitive to chloroquine. Other uses include treatment of rheumatoid arthritis, lupus, and porphyria cutanea tarda. It is taken by mouth, often in the form of hydroxychloroquine sulfate.
Trazodone, sold under many brand names, is an antidepressant medication. It is used to treat major depressive disorder, anxiety disorders, and insomnia. The medication is taken orally.
Naringin is a flavanone-7-O-glycoside between the flavanone naringenin and the disaccharide neohesperidose. The flavonoid naringin occurs naturally in citrus fruits, especially in grapefruit, where naringin is responsible for the fruit's bitter taste. In commercial grapefruit juice production, the enzyme naringinase can be used to remove the bitterness (debittering) created by naringin. In humans naringin is metabolized to the aglycone naringenin by naringinase present in the gut.
Some fruit juices and fruits can interact with numerous drugs, in many cases causing adverse effects. The effect is most studied with grapefruit and grapefruit juice, but similar effects have been observed with certain other citrus fruits.
Artemether/lumefantrine, sold under the trade name Coartem among others, is a combination of the two medications artemether and lumefantrine. It is used to treat malaria caused by Plasmodium falciparum that is not treatable with chloroquine. It is not typically used to prevent malaria. It is taken by mouth.
Nitrendipine is a dihydropyridine calcium channel blocker. It is used in the treatment of primary (essential) hypertension to decrease blood pressure and can reduce the cardiotoxicity of cocaine.
Bergamottin (5-geranoxypsoralen) is a natural furanocoumarin found in the pulp of pomelos and grapefruits. It is also found in the peel and pulp of the bergamot orange, from which it was first isolated and from which its name is derived.
Pravadoline (WIN 48,098) is an anti-inflammatory and analgesic drug with an IC50 of 4.9 μM and a Ki of 2511 nM at CB1, related in structure to nonsteroidal anti-inflammatory drugs (NSAIDs) such as indometacin. It was developed in the 1980s as a new antiinflammatory and prostaglandin synthesis inhibitor, acting through inhibition of the enzyme cyclooxygenase (COX).
Piperaquine is an antiparasitic drug used in combination with dihydroartemisinin to treat malaria. Piperaquine was developed under the Chinese National Malaria Elimination Programme in the 1960s and was adopted throughout China as a replacement for the structurally similar antimalarial drug chloroquine. Due to widespread parasite resistance to piperaquine, the drug fell out of use as a monotherapy, and is instead used as a partner drug for artemisinin combination therapy. Piperaquine kills parasites by disrupting the detoxification of host heme.
Atovaquone/proguanil, sold under the brand name Malarone among others, is a fixed-dose combination medication used to treat and prevent malaria, including chloroquine-resistant malaria. It contains atovaquone and proguanil. It is not recommended for severe or complicated malaria. It is taken by mouth.
