Protease inhibitors are different substances that can inhibit the body’s own proteases in their function. They can be peptides, proteins, or some low-molecular-weight substances. There are poisons, such as scorpion or snake venoms, which belong to the protease inhibitors. From this, it can be seen that protease inhibitors can be very dangerous. In medicine, protease inhibitors are used, among other things, to serve as anticoagulants, in the form of antihypertensives to lower high blood pressure, or in the form of antivirals to be helpful in HIV or HCV infections.
What are protease inhibitors?
All substances that inhibit the body’s own proteases in their mode of action can be summarized under the term protease inhibitors. Proteases are enzymes that are now called peptidases. The term proteases is outdated, but it helps to better understand what protease inhibitors are for. Peptidases or proteases have the task of cleaving proteins. Since protease inhibitors inhibit these enzymes, this inhibits or even prevents the cleavage of these proteins.
Pharmacologic action
The effects of naturally occurring protease inhibitors can be quite lethal. This is the case, for example, with snake and scorpion venoms, which are among the naturally occurring protease inhibitors. In medicine, however, the judicious use of protease inhibitors can save lives. Four types of proteases can be inhibited, namely serine proteases, cysteine proteases, metalloproteases and aspartate proteases. There are different protease inhibitors for each form of proteases that are targeted to a specific one of these four mentioned proteases. In addition, there are some that can inhibit different proteases. It is important to pay attention to the correct dosage here, as even the protease inhibitors used in medicine can be very toxic if overdosed.
Medical application and use
In medicine, well-known protease inhibitors are those used to inhibit blood clotting, to regulate high blood pressure, and to treat HIV and HCV infections. Anticoagulants are also called anticoagulants. They are used to reduce excessive blood clotting. There are several different anticoagulants. These include the coumarins, also called vitamin K antagonists, the heparins, the direct oral anticoagulants (which intervene directly in the clotting cascade), all substances containing hirudin, or the calcium complexing agents. Protease inhibitors in the form of antihypertensives are used to lower blood pressure. These can be, for example, beta blockers and calcium channel blockers, which inhibit calcium influx. ACE inhibitors, aldosterone antagonists and AT1 antagonists inhibit the renin-angiotensin-aldosterone system. Similarly, all forms of diuretics, i.e., dehydrating agents that lower blood pressure in this way, belong to the protease inhibitors. Antivirals also belong to the protease inhibitors. They inhibit the reproduction of viruses in the body. These include viruses in diseases such as HIV, where the use of protease inhibitors is particularly helpful. The mode of action of antivirals varies. Some prevent docking to the cell membrane of the host organism, others prevent penetration into the host cell, and some prevent the formation of new viruses or the release of newly formed viruses from the host cell.
Risks and side effects
All protease inhibitors must be used very carefully. As helpful as antivirals can be on the one hand, they can become dangerous on the other, because they can not only attack the cells of the viruses but also, in the case of an overdose, bring the entire cell life of the treated organism to a halt, which would have life-threatening consequences. In the case of anticoagulants, it should always be borne in mind that, on the one hand, there may be allergic reactions to them, but, on the other hand, if the wrong dosage is taken, it may lead to too strong and thus life-threatening an inhibition of blood coagulation. With regard to all the blood pressure lowering drugs that belong to the protease inhibitors, it should be said that each of them can bring various side effects and risks. Due to the diuretic effect, the body can become dehydrated, there can be severe electrolyte losses and corresponding disturbances in the body, and in the worst case, the tendency to thrombosis increases due to thickened blood.Convulsions, states of confusion, cardiac arrhythmias or blood pressure that is much too low can also occur during treatment with protease inhibitors. It is therefore important to be especially cautious when using all forms of protease inhibitors.
