Active Ingredients

Saquinavir – Effect, Application & Risks


The active substance saquinavir is a protease inhibitor . The drug is primarily used to treat HIV infections . The substance saquinavir is mainly used in combination preparations. The drug was approved in 1995. Since a large number of patients quickly developed resistance to the drug, saquinavir was withdrawn from the pharmaceutical market for a short time. An improved preparation has been available since 1997.

What is saquinavir?

The substance saquinavir is characterized by antiviral properties and is used to treat HI viruses . Saquinavir inhibits various viral processes, in particular the protease. This is primarily responsible for the maturation and multiplication of the virus .

Administration is twice a day by the oral route. The tablets are taken after a meal. As a rule, the drug saquinavir is administered together with the active substance ritonavir .

The drug is sometimes also referred to interchangeably as saquinavirum or saquinavir mesylate . In pharmaceutical use, saquinavir exists as saquinavir mesylate. This is a powder that is slightly hygroscopic and white in color. The substance is virtually insoluble in water.

Pharmacological action

Basically, the active ingredient saquinavir is an HIV protease inhibitor. Thus, the drug interferes with HIV protease. This is a viral enzyme that plays a central role in the formation of new viruses. For this reason, the active ingredient saquinavir helps to delay the multiplication of the HI virus in the human organism.

If the substance saquinavir is taken alone, the bioavailability is usually too low, so that the effect is not sufficient. Because saquinavir is largely broken down into relatively ineffective metabolites. Therefore, in modern times, the drug is commonly combined with ritonavir. It is also an HIV protease inhibitor. Both active ingredients together lead to a higher concentration of the drugs in the blood plasma , which significantly increases their effectiveness.

The active ingredient saquinavir is rapidly broken down in the liver . The cytochrome system is primarily responsible for degradation. If ritonavir is taken at the same time, this leads to a slowdown in the hepatic breakdown of saquinavir, so that the substance has a longer effect. Also, in some cases, the drug is combined with reverse transcriptase inhibitors. In principle, the active ingredient saquinavir leads to a reduction in viral load.

Medical Application & Use

Saquinavir is used in the majority of cases to treat HIV infections. In particular, the active ingredient is used in the therapy of HIV-1 infected adults. Other antiretroviral drugs are usually used to increase the effect of saquinavir. The corresponding therapy method is called HAART or highly active antiretroviral therapy.

The dosage of the drug Saquinavir takes place according to the information for professionals. It is usually taken in the form of tablets that are administered orally. These tablets are taken twice a day after meals. In most cases, a combination therapy with the active ingredient ritonavir is carried out. This substance is a so-called CYP inhibitor, which slows down the metabolism of saquinavir.

Risks & side effects

In the context of therapy with saquinavir, various undesirable side effects and other complaints are possible. These must be carefully considered by a doctor when prescribing the active ingredient. The anamnesis , i.e. the discussion of the medical history of the affected patient, plays a central role. This is because the treating doctor analyzes the patient’s history and family dispositions.

The side effects from the drug saquinavir occur with different frequencies. Symptoms of the gastrointestinal tract , such as nausea , abdominal pain and diarrhea , are most common when taking saquinavir . Peripheral neuropathies and headaches are also possible.

In addition to the potential side effects of saquinavir, there are a few contraindications to consider before taking the drug for the first time. If the person in question suffers from hypersensitivity to the active substance saquinavir, therapy with the drug must be avoided. In this case, possible alternatives for treatment must be found. The drug is also contraindicated in the presence of severe liver failure . The complete notes regarding the contraindications are listed in the prescribing information of the drug saquinavir.

In addition, before starting therapy with saquinavir, it should be noted that there are various interactions with other active ingredients. For example, do not take pimozide , midazolam , stavudine , didanosine , efavirenz and clarithromycin at the same time . Because these substances interact with the cytochrome system that is responsible for breaking down saquinavir. As a result, changes in the plasma level occur which, among other things, lead to poor controllability of the effect of saquinavir.

Basically, saquinavir is a substrate of the substance CYP3A4. Therefore, interactions with inhibitors or inducers of CYP may occur when taken concomitantly with saquinavir.

In principle, all side effects that occur should be reported to a doctor in order to decide on the further course of treatment. Discontinuation may be necessary if complications from saquinavir are severe.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.