NewsMolnupiravir: The dangerous side effects of the corona drug

Molnupiravir: The dangerous side effects of the corona drug

The approval of molnupiravir in the US was on the brink. A Swiss expert warns against careless use of the drug.

After the mRNA vaccines from Biontech, Moderna, the vector vaccine AstraZeneca, the protein-based vaccines Novavax* and Sanofi* and the inactivated vaccine from Valneva*, the focus is now on corona drugs. Molnupiravir is already available. The tablet from the US pharmaceutical company Merck & Co. is marketed under the brand name Lagevrio. Severe side effects are often forgotten.

Doctors in Germany have been able to prescribe the corona drug Molnupiravir (Lagevrio) to patients since January 2022. In Europe, however, approval by the European Medicines Agency (EMA) is still missing. The Federal Institute for Drugs and Medical Devices (BfArM) was a little faster*.

Molnupiravir: emergency approval of the corona drug – expert warns

The tablets against Corona are already available in England. A look at America, however, massively curbs the joy of the speedy release. As the Deutsche-Apotheker-Zeitung (DAZ ) reports in an article, “the US Food and Drug Administration’s advisory board only recommended the emergency use approval of the COVID-19 drug by a narrow majority: 13 votes in favor of approval and ten against .”

In December 2021, Urs Greber, Professor of Molecular Cell Biology at the University of Zurich, was quoted on the Swiss platform – an independent magazine for knowledge – about the process in the USA: “I was very surprised by the decision of the advisory board. To be honest, I find that quite careless and incomprehensible.”

Mode of action of the corona drug molnupiravir: there are dangers here

The DAZ describes the mode of action of molnupiravir as follows: “Molnupiravir and its metabolite (N4-hydroxycytidine) resemble an RNA and DNA building block in terms of their chemical structure. This fact is a prerequisite for the antiviral effect of molnupiravir. The installation of this wrong building block leads to errors in the RNA chain of the virus – i.e. the genetic information of SARS-CoV-2 – so that it can no longer multiply and is no longer able to survive.”


According to the definition, metabolites are substances that arise as intermediate stages or degradation products of metabolic processes in the organism. In biochemistry, a distinction is made between anabolites and catabolites. Anabolites are molecules that occur as intermediates in synthesis. Catabolites are substances that are formed during the breakdown of compounds endogenous or ingested from exogenous sources.

The higgs article sums it up succinctly: “The active ingredient causes the wrong building block of the RNA to be built into the genome of the coronavirus. This process happens randomly at different locations in the viral genome (genetic material). “If the genome contains many errors, the control mechanism of the virus cannot correct them, the replication of the virus stops – the infection is stopped” .

The genome

According to the definition, the genome – or the genetic material of a living being or a virus – is the entirety of the material carriers of the hereditary information of a cell or a virus particle. The genetic information (genetic material) can be stored in a chromosome, an entire set of chromosomes or directly in the form of DNA or RNA.

However, with the “implantation” of errors in the genetic material of the virus, massive problems can also arise for the patient. These consequences can have major effects on the body.

Possible erroneous effect of molnupiravir

The problem with molnupiravir arises when, according to Professor Urs Greber, the drug causes only a few of the desired errors in the virus. This can happen “when the concentration of the active ingredient in the cells is low – for example, because someone forgets to swallow a pill. As a result, the virus’s corrective mechanisms might eradicate some bugs but not others, and the virus would continue to multiply .”

The expert is very clear: “Nobody can say how high the probability of this is. This is potentially dangerous because you don’t know which mutations occur and what they do.” For him, the application remains “risky and increases the risk of viral mutations”.

Corona drug: The side effects – mutation by molnupiravir

According to Professor Urs Greber, with the way the corona drug works, there is a definite possibility that molnupiravir can “change cellular gene activity” . The Deutsche-Apotheken-Zeitung confirms such consequences in its report: “This has already been demonstrated in vitro, i.e. in the test tube (including in bacteria), but not yet in vivo (this has been investigated in transgenic rodents, among other things).”

Nevertheless, according to numerous scientists, the risk of treatment with molnupiravir (Lagevrio) is classified as rather low. However, it is explicitly discouraged from taking it during pregnancy. As reported by the DAZ, there are non-clinical studies on reproductive toxicology in male and female rats, preliminary studies on embryo-foetal development in rats and rabbits, and a study on pre- and postnatal (before and after birth) development in rats.

In embryo-foetal development studies in rats, reduced fetal body weight and external (eye), visceral (absent kidney, cardiovascular malformations) and skeletal malformations (abnormalities and delays in ossification, increased incidence of rib malformations, thoracic and lumbar vertebral malformations and skull malformations) were observed .

Molnupiravir side effects: Bone and cartilage malformation

The previous studies have shown that the use of the corona drug molnupiravir is not without problems for bones and cartilage. In the statements on this, the DAZ refers to a three-month study on rats. Abnormal bone and cartilage formation were noted here, and rat and rabbit fetuses showed delayed and incomplete ossification in embryo-foetal development studies.

Experts and manufacturers agree that “molnupiravir should not be approved for use in patients under the age of 18” . Professor Urs Greber is also certain about the product from the US manufacturer: “The drug’s profit is rather small.” He also explains in the higgs article that he does not see this drug as a game changer in the pandemic.

Other corona drugs: Paxlovid and Atriva in development

In addition to Molnupiravir (Lagevrio), Paxlovid, another drug against Corona, is currently waiting in the starting blocks. A comparison between the two products has already shown advantages for a tablet. In Germany, too, a corona drug* could soon be developed with Atriva. Studies are already underway in Tübingen. * is an offer from IPPEN MEDIA.

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