Neuraminidase inhibitors

Neuraminidase inhibitors are antiviral medications mainly used to treat influenza, which is the virus that causes the flu.

There are three types of influenza viruses that infect humans; type A, type B, and type C, and each one has a slightly different genome and set of proteins.

Now, neuraminidase inhibitors work by preventing the release of new viruses from infected cells, thereby limiting the duration of the illness.

Alright, first let’s focus on influenza A and influenza B. These viruses have two types of glycoproteins on their protective envelope: H protein, or hemagglutinin; and N protein, or neuraminidase.

When the flu virus enters the body, it uses hemagglutinin to bind to sialic acid sugars on the surface of epithelial cells in the upper respiratory tract.

Once bound, the cell swallows up the virus in a process called endocytosis. Next, the virus releases its viral RNA which moves into the cell’s nucleus.

Now, these RNAs are negative-sense, meaning they need to be transcribed by RNA polymerase into positive-sense mRNA strands.

These strands leave the nucleus and are translated into proteins by ribosomes. These proteins are then assembled into new viruses.

Now that we have a cell that’s pretty much a virus-producing factory, it will continue to produce more and more viruses which bud off the host cell’s plasma membrane and leave the body.

However, the same hemagglutinin that allowed the virus to attach to the sialic acid sugar on the cell surface, can bind to these sugars again and prevent the viruses from leaving the host cell.

So, in order to be released, the virus uses the neuraminidase proteins to cleave the sialic acid and free itself. So in short, hemagglutinin allows the virus to enter the cell, while neuraminidase lets the virus leave the cell.

Now, neuraminidase inhibitors, as their name implies, bind and inhibit the enzyme neuraminidase, thereby preventing the release of new viruses.

Common medications in this class include oseltamivir, which is taken perorally as a pill, and zanamivir, which is taken as a powder inhaled by mouth.

It’s important to note that these medications only work on influenza A and influenza B, but not on influenza C because influenza C doesn’t have the enzyme neuraminidase.

These medications can be used for both treatment and prophylaxis against influenza. Oseltamivir can be used for the treatment and prophylaxis of influenza in individuals over the age of 1, but zanamivir is used in people over the age of 7.

When used for treatment, the best result is seen if the medications are used early, within 2 days of showing symptoms. But it can also be used prophylactically in individuals, in order to lessen the severity, duration, and risk of complications associated with influenza; especially in high-risk groups, such as young children, elderly individuals, pregnant women, and immunosuppressed individuals.Switching gears and moving on to side effects, oseltamivir can cause gastrointestinal disturbances such as nausea, vomiting, dyspepsia, and diarrhea; but these are less common with zanamivir, since it’s inhaled directly into the lungs.

On the other hand, it’s important to note that zanamivir should be avoided in individuals with underlying airway conditions, such as asthma or chronic obstructive pulmonary disease because it can cause bronchospasms.Now, we want to make a simple and fun mnemonic that’ll help you efficiently memorize and retain all these pharmacology facts!

Okay, so let’s go to the jungle, where scientists have put two mirrors to study how animals react to their reflection. The mirrors help you remember that neuraminidase inhibitors end in “mivir,” and one’s labeled “A” and the other is labeled “B” since they are used to treat and prevent influenza A and B infections.

Okay, for the specific drugs, let’s use an ostrich for oseltamivir and an anaconda who’s coiled into a “Z” shape for zanamivir, and they’re both checking out the mirrors.

For side effects, the ostrich is vomiting to represent the GI distress and also to help you remember it’s a pill taken perorally.

For the anaconda, let’s put a noose around its neck since this inhaled medication could cause bronchospasms, so it’s contraindicated in people with asthma.

##SummaryAll right, as a quick recap. Neuraminidase inhibitors are antiviral medications used for the treatment and prophylaxis of influenza A and influenza B, which are viruses that cause the flu.

Common medications in this class include oseltamivir, which is taken as a pill; and zanamivir, which is taken as a powder for inhalation.

These medications work by inhibiting the enzyme neuraminidase, thereby preventing the release of new virions and further infection of the host’s cells.

Common side effects of oseltamivir include gastrointestinal disturbances, while zanamivir should be avoided in individuals with underlying airway conditions because it can cause bronchospasms.