Diovan (Valsartan) acts selectively on the Angiotensin receptor subtype. Valsartan is an antagonist which works by blocking the Angiotensin 2 receptors. This in turn prevents the production of Angiotensin 2 hormone. Angiotensin 2 is the hormone which is responsible for narrowing blood vessels to increase the blood pressure when the blood pressure level is not at the appropriate level. When the hormone is blocked, the blood vessels will not therefore be narrowed and blood pressure level is maintained.
The other effect is that when Angiotensin 2 is blocked, the production of the hormone Aldosterone is also blocked which increases the amount of fluid removed in the body. Reducing the volume of fluids in the blood vessels reduces the blood pressure in the blood vessels. Valsartan therefore aids in more than one action in reducing the blood pressure, in which the first includes preventing the narrowing of the blood vessels and secondly by reducing the volume of fluids in the body. Diovan is used with patients suffering from hypertension and is also used to improve survival in people with a poorly functioning heart.
Cozaar (Losartan potassium) acts as an antagonist for Angiotensin 2 receptor. Losartan potassium is an antagonist which works by blocking the Angiotensin 2 receptors. This in turn prevents the production of Angiotensin 2 hormone. Angiotensin 2 is the hormone which is responsible for narrowing blood vessels to increase the blood pressure when the blood pressure level is not at the appropriate level.
When the hormone is blocked, the blood vessels will not therefore be narrowed and blood pressure level is maintained. Blocking the production of Angiotensin 2 also prevents the production of the hormone Aldosterone and its action on the kidney. This causes an increase in the amount of fluid removed from the body which therefore reduces the pressure in the blood vessels. Both these actions work hand in hand in reducing the blood pressure in the body.
The similarity between the above drugs is that a number of them act on specific receptors. MabThera, Zyban, Singulair, Avonex, Combivent, Diovan and Cozaar all act on receptors. There are 4 different types of receptors in which these drugs can act on. 1) Ligand gated 2) G-Protein coupled 3) Kinase linked 4) Nuclear (Steroids). Each of the above receptors differs from one another for example in signal transmission speed. Ligand gated receptors respond in milliseconds whereas G-Protein coupled receptors respond in seconds. On the other hand Kinase linked receptors and nuclear receptors respond in hours.
Navispare is the only drug out of the 10 drugs mentioned above that acts on ion channels. It promotes the secretion of certain ions (sodium-chloride transporter). Navispare, Diovan and Cozaar are all used for the treatment of hypertension. All three drugs are used to lower the blood pressure. Diovan and Cozaar have the same molecular target which is the Angiotensin 2 receptor. The Angiotensin 2 system is responsible for narrowing the blood vessels and reducing the amount of fluid filtered in the kidney. Both drugs prevent the secretion of Angiotensin 2, by acting as an antagonist on the receptor.
Navispare on the other hand only targets the kidney and the ion channels in particular. Navispare increases the amount of filtered fluid out of the kidney thus reducing the volume of fluids in the blood vessels thus reducing the blood pressure. Combivent and Singulair both aid the dilation of the airways. Each of the drugs has a different molecular target. Singulair acts by blocking the secretion of leukotriene.
Leukotriene promotes the secretion of mucous and also promotes inflammation. Singulair blocks Leukotriene which in turn prevents the constriction of the airways. Combivent on the other hand contains two active ingredients to aid the treatment. One of the ingredients is used to relax the muscles in the airways (Salbutamol sulphate), whereas the other is used to for binding to acetylcholine receptors thus inhibiting vagally mediated reflexes (Ipratropium bromine).
Celebrex (Celecoxib) acts by inhibiting the cyclooxygenase 2 enzyme. It functions by selectively inhibiting the enzyme. Celebrex is a pain reliever due to the fact that it inhibits the Cyclooxygenase 2 enzyme (COX-2). Cyclooxygenase 2 is the isoform of the enzyme responsible for inflammation and pain. The enzyme produces prostaglandin which triggers inflammation. Celebrex is used for patients suffering from Rheumatoid arthritis, Ankylosing spondylitis and Osteoarthritis
Avandamet consists of two active ingredients on which the first one (Rosiglitazone maleate) acts on pancreatic B-Cell and the second one being (Metmorfin hydrochloride) acting on the glycogen synthesis enzyme. Rosiglitazone maleate is a type of antidiabetic medicines known as a thiazolidinedione or glitazone. It reduces the blood sugar level by increasing the sensitivity of liver, muscle and fat cells to insulin. This will then allow the cells to remove sugar from the blood more efficiently. Metmorfin hydrochloride is also an antidiabetic called biguanide. It functions by reducing the amount of sugar produced by the liver cells. It also increases the sensitivity of muscle cells to insulin. Finally it delays absorption of sugars from the intestines. Avandamet is used to treat patients suffering from Type 2 (non-insulin dependent) diabetes.
Celebrex and Avandamet work by either activating or inhibiting a particular enzyme. They function because they either have the same molecular shape as the substrate that the binds on to the enzyme or in other cases they bind to areas other than the active site of the enzyme which means that the there is no competition between the drug and the substrate. Celebrex functions by inhibiting cyclooxygenase 2 enzyme while in Avandamet Metmorfin hydrochloride acts on the glycogen synthesis enzyme. The similarity about Celebrex and MabThera is that both drugs are used to treat arthritis. The similarity between all the drugs hence their molecular target is that they all have a negative effect, either on a receptor or on an enzyme. If the drug is acting on a receptor, then the drug is an antagonist or if it is acting on enzyme, it inhibits the function of the enzyme.
References:
1) www.netdoctor.co.uk
2) www.medicines.og.uk