atovaquone

Action and Spectrum

Actions and Spectrum:

Actions:

The actions of atovaquone involve inhibiting the electron transport chain in the mitochondria of these protozoa, thereby disrupting their energy production and causing their death. atovaquone can also interfere with the replication of these protozoa, further preventing their growth and spread.

Spectrum:

The spectrum of atovaquone refers to the range of microorganisms the medication can effectively treat or prevent. atovaquone has a narrow spectrum of activity and is primarily effective against certain protozoa, such as Pneumocystis jirovecii, Plasmodium spp., and Babesia spp.

Drug Interaction

Adverse Reaction

Frequency Defined

>10%

Cough

Depression

Abdominal pain

Diarrhea

Headache

Infection

Dyspnea

Fever

Insomnia

Rhinitis

Vomiting

Myalgia

Nausea

Rash

Weakness

1-10%

Anorexia

Anxiety

BUN/creatinine increased

Amylase increased

Anemia

Constipation

Dyspepsia

Dizziness

Hypoglycemia

Hyponatremia

Hyperglycemia

Liver enzymes elevated

Oral moniliasis

Neutropenia

Pruritus

Taste perversion

Black Box Warning

Black Box Warning:

None

Contraindication / Caution

Contraindication/Caution:

atovaquone may not be suitable for everyone, and some contraindications and cautions should be considered before prescribing or taking the medication.

Contraindications:

• Known hypersensitivity or allergy to atovaquone or any of its components
• Severe renal impairment (when rate of creatinine clearance < 30 mL/min)
• Pregnancy and breastfeeding (due to limited safety data)

Caution should be exercised when using atovaquone in patients with:

• Hepatic impairment (as atovaquone is primarily metabolized in the liver)
• Gastrointestinal disorders (as atovaquone may cause diarrhea, nausea, and vomiting)
• Concurrent use of other medications that may affect the liver or renal function

Electrolyte imbalances, such as atovaquone, can cause hyperkalemia (increased potassium levels) or hypomagnesemia (decreased magnesium levels)

Pregnancy / Lactation

Pregnancy consideration:

Pregnancy Category: C

Breastfeeding warnings:

The excretion of the drug in breast milk is unknown hence use the drug cautiously.

Pregnancy category:

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester.
• Category B: No evidence of risk to the fetus is found in animal reproduction studies, and there are not enough studies on pregnant women.
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for a human product; Pregnant women must take care of the potential risks.
• Category D: There is adequate data with sufficient evidence of human fetal risk from various platforms. However, despite potential dangers may be used only in emergencies for potential benefits.
• Category X: Drugs listed in this category outweigh the risks over benefits. The drug is not for pregnant women.

Category N: No data is available for the drug under this category.

Pharmacology

Pharmacology:

atovaquone is a medication that belongs to the class of antiparasitic agents. It works by inhibiting the mitochondrial electron transport chain in protozoa, disrupting energy production and ultimately resulting in their death.

atovaquone is a hydroxy-1,4-naphthoquinone with a lipophilic structure, allowing it to cross cell membranes readily.

Pharmacodynamics:

The pharmacodynamics of atovaquone involve its mechanism of action in inhibiting the mitochondrial electron transport chain in protozoa. atovaquone selectively targets the cytochrome bc1 complex in these organisms’ mitochondrial electron transport chain, which leads to inhibition of the electron transport chain and ultimately results in the depletion of cellular adenosine triphosphate (ATP), leading to the death of the parasites.

Pharmacokinetics:

Absorption

The absorption is significantly increased with a fatty meal

The bioavailability for tablets is 23%, and suspension is 47%

Distribution

The volume of distribution is 3.5 L/kg

The protein-bound is more than 99%

Metabolism

The drug undergoes enterohepatic recirculation

Elimination and Excretion

The half-life of elimination is 2-3 days

94% of unchanged drug is excreted in feces

Adminstartion

Administration:

atovaquone is available in several formulations, including oral tablets and oral suspension. The administration of atovaquone may vary depending on the specific indication and the age and weight of the patient.

Patient Information Leaflet

Patient information leaflet

Generic Name: atovaquone

Pronounced: a-TOE-va-kwone

Why do we use atovaquone?

atovaquone is a medication used for the treatment and prevention of various protozoal infections, including:

• Pneumocystis jirovecii pneumonia: atovaquone is an alternative medication to trimethoprim-sulfamethoxazole (TMP-SMX), the first-line treatment for Pneumocystis jirovecii pneumonia. It is effective in treating and preventing this type of pneumonia in patients with HIV/AIDS and other immunocompromised conditions.
• Malaria:  atovaquone is used in combination with proguanil to treat and prevent malaria caused by Plasmodium falciparum andPlasmodium vivax. The medication is effective against chloroquine-resistant strains of malaria.
• Babesiosis: atovaquone is used in the treatment of babesiosis, a parasitic infection transmitted by ticks. It is often used in combination with azithromycin for optimal efficacy.