Tecovirimat Capsules - Indication, Pharmacology, Warnings, and Precautions

Overview:

Tecovirimat is an antiviral medication used to treat smallpox. It works against the majority of orthopoxviruses, such as the variola (smallpox) viruses, vaccinia, cowpox, ectromelia, rabbitpox, and monkeypox. It can be used to treat smallpox vaccination-related problems brought on by the vaccinia virus's replication, as well as adult and pediatric cowpox and monkeypox infections. Tecovirimat comes in both oral and intravenous forms. As the first specialized therapeutic agent for the treatment of smallpox, the medication was approved by the US FDA (United States Food and Drug Administration) in July 2018. It does not cure viral diseases like the flu or colds.

Drug Group:

Tecovirimat is an anti-viral drug. Adults and children weighing at least 13 kilograms (28.66 pounds) can be treated for smallpox using Tecovirimat, an inhibitor of the orthopoxvirus VP37 envelope-wrapping protein.

Dosage:

1. For Adults: Based on body weight, for 14 days.

• For Patients Weighing 40 to 120 kg: 600 mg (milligrams) twice daily, which corresponds to taking three capsules twice daily.

• For Patients Weighing 120 Kg or More: 600 mg three times daily, requiring three capsules per dose, taken three times daily.

2. For Pediatric Patients: Based on body weight for 14 days.

• 13 Kg and Less Than 25 Kg: 200 mg twice daily, which is the contents of one capsule, mixed with 30 mL (milliliter) of liquid or soft food and administered as a whole mixture.

• 25 kg and Less Than 40 Kg: 400 mg twice daily, which equates to two capsules mixed with 30 mL (milliliter) of liquid or soft food.

For Patients:

Indication:

Tecovirimat is indicated for the treatment of smallpox caused by the variola virus in adults and pediatric patients weighing at least 13 kg ((28.66 pounds).

Contraindication: None

Limitations of Tecovirimat Capsules:

Since ethical and practical constraints prevent well-controlled field trials or intentionally inducing smallpox in humans, the efficacy of Tecovirimat capsules has not been established in humans. However, studies in the immunocompromised animal model suggest that the effectiveness of Tecovirimat capsules could be diminished in immunocompromised patients.

How Are Tecovirimat Capsules Used for Human Smallpox Disease?

The variola virus, which belongs to the orthopoxvirus family, is the cause of smallpox, an acute and infectious disease. Before it was eradicated, it was one of the most deadly illnesses in history, killing millions of people.

Early signs of smallpox include high fever, extreme fatigue, backache, and, less frequently, abdominal pain and vomiting. By two to three days into the disease, a characteristic rash begins on the face and hands and spreads to all parts of the body. These rashes appear as pimples filled with clear fluid that becomes filled with pus and crusted over, then dry and fall off. Rashes can also appear inside the nose and mouth mucous membranes, where they quickly ulcerate.

It is spread through infective droplets when in close contact with infected persons or, less commonly, through contaminated clothing and bedding. The incubation period is seven to 17 days, and it only becomes infectious when the patient develops a fever. In fact, the patient continues to be contagious until all of the scabs fall off.

How Should Tecovirimat Capsules Be Used?

Swallow Tecovirimat capsules with food and follow the instructions on the prescription label. Always take them at the same time each day, and do not take more than prescribed. Complete the entire course, even if you feel well. Do not miss any doses or terminate the treatment early. Consult your pediatrician about using this medicine in children because specific precautions are needed.

What Are the Side Effects of Tecovirimat Capsules?

If you have any of the following, immediately contact your doctor or pharmacist for advice. Symptoms of an allergic reaction: rash, itching, hives (itchy red bumps), or swelling of the face, lips, or tongue, and changes in mood or emotions. Besides these symptoms, headache, nausea, vomiting, and stomach pain occur frequently but are not serious enough so that you do not go to see your doctor at once; you should, however, if it persists or bothers you.

What Are the Things to Inform the Doctor Before Taking Tecovirimat Capsules?

Inform your doctor if you have diabetes, immune system problems, allergies to other medicines or foods, dyes or preservatives, are pregnant or planning for a baby, or breastfeeding.

Overdose:

Contact a poison control center or seek emergency medical assistance right away if you think you may have overdosed. You are administered Tecovirimat capsules specifically for your condition. Never share it with anyone else.

Missing Dose:

If you forget to take a dose, take it as soon as you remember unless the next dose is less than eight hours away. At the appointed time, take your next dose and skip the one you missed.

Drug Interactions:

Some drugs with potential interaction include midazolam, Repaglinide, and the live vaccine for smallpox. This is not a complete list of all interactions, so you are cautioned to provide a more extensive list of any prescriptions, herbal remedies, OTC (over-the-counter) medications, and nutrition supplements that you have at your disposal. Provide a history of smoking and or alcohol intake and if you are taking illegal drugs due to their influence in the change of action of some medicines administered.

For Doctors:

Clinical Pharmacology

• Chemical Name: Benzamide,N-[(3aR,4R,4aR,5aS,6S,6aS)-3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6 ethenocycloprop[f]isoindol-2(1H)-yl]-4-(trifluoromethyl), rel-(monohydrate).

• Chemical Formula: C19H15F3N2O3·H2O.

• Appearance: White to off-white crystalline solid.

• Inactive Ingredients: Colloidal silicon dioxide, croscarmellose sodium, hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and sodium lauryl sulfate.

Mechanism of Action

By specifically targeting the VP37 protein in orthopoxviruses, Tecovirimat prevents the virus from interacting with other cell components that are necessary for the virus to spread throughout the body. In cell experiments, Tecovirimat efficiently lessens the effects of a number of viruses, such as monkeypox and smallpox, at low doses. Although Tecovirimat-resistant orthopoxviruses are not known to occur naturally at this time, treatment-induced resistance may arise as a result of VP37 protein alterations. Since Tecovirimat and another antiviral, Brincidofovir, function differently, resistance to one does not impact the efficacy of the other.

Pharmacodynamics - At expected therapeutic doses, Tecovirimat does not considerably lengthen the QT interval.

Pharmacokinetics

• Absorption: Tecovirimat is well absorbed among healthy adults when administered via the oral route. The time to reach maximum concentration was roughly six hours, and in four to six days, it achieved stable levels. Tecovirimat gets absorbed better in the presence of food; a high-calorie, high-fat meal would increase exposure by 39 percent.

• Metabolism: The UDP glucuronosyltransferases UGT1A1 and UGT1A4 metabolize Tecovirimat in the body. TFMBA, M4, and M5 are the three major metabolites formed by this metabolism. These are pharmacologically inactive. Moreover, glucuronide conjugates were not identified in plasma. So far, the molecular structure of Tecovirimat's metabolites is not yet known.

• Excretion: Tecovirimat is excreted from the body through the kidneys and metabolism. About 23 percent of the dose administered is recovered in the stools after oral administration, primarily as the unchanged drug, and 73 percent is excreted in urine, primarily as glucuronidated metabolites. The two major forms of Tecovirimat excreted in the urine are the primary glucuronide conjugate and the M4 glucuronide conjugate, accounting for about 24.4 and 30.3 percent of the dosage, respectively.

• Protein Binding: Tecovirimat binds to 77 to 82 percent of human plasma proteins.

Drug Warnings and Precautions:

• Hypoglycemia When Co-Administered with Repaglinide - The use of Repaglinide in combination with Tecovirimat results in mild to moderate hypoglycemia. Blood glucose should be monitored and symptoms of low blood sugar observed in a patient receiving Tecovirimat in combination with Repaglinide. In a study involving 30 healthy volunteers, 10 experienced mild to moderate hypoglycemia following administration of two milligrams of Repaglinide in combination with Tecovirimat; all symptoms resolved after ingestion of food or oral glucose administration.

Use in Specific Populations:

• Pregnancy - The safety of Tecovirimat during pregnancy has not been shown by well-controlled research in pregnant women, thus it is unsure if there is any danger. Tecovirimat does not appear to harm the fetus, according to research on mice and rabbits.

• Lactation - There is no information available on the effect of Tecovirimat on milk production, passage into human breast milk, or effect on infants who are breastfed. In a study involving lactating mice, Tecovirimat was detected in the milk. The decision regarding the treatment with Tecovirimat must be balanced between the benefit of breastfeeding for the mother and the infant against the mother's desire for the drug and the possible risk of the drug to the child or the condition of the mother.

• Pediatric Population - The efficacy of Tecovirimat in children, as well as in adults, was based solely on studies carried out on animal models of orthopoxvirus disease. Children's dosing was determined through pharmacokinetic modeling to achieve exposure levels observed in adults at a dose of 600 mg twice daily because it would be unethical to conduct clinical trials of Tecovirimat in healthy children without a medical indication. Pediatric dosages are adjusted for the weight of the child.

• Renal and Hepatic Impairment - Patients with mild, moderate, or severe renal impairment, including those with end-stage renal disease (ESRD) that require hemodialysis, do not require a dosage adjustment. No adjustment is needed for patients with mild, moderate, or severe hepatic impairment (Child-Pugh Class A, B, or C).

• Geriatric Population - It is unknown whether the safety profile of Tecovirimat varies in older persons compared to younger ones because clinical trials only involved a small number of participants 65 and older. For individuals 65 and older, there is no need to change the dosage.

Clinical Studies:

The rates of adverse reactions for Tecovirimat will vary in real-life use and cannot be compared to other medications because clinical studies differ in terms of settings. No research has been done on Tecovirimat's safety in real smallpox patients. Tecovirimat was administered to 359 healthy persons aged 18 to 79 in a phase 3 experiment. 10 percent were 65 years of age or older. 336 of them finished the majority of the 14-day course of 600 mg twice a day. The most frequent adverse effects were nausea and headache.