(Nitrates ) treatment for Coronary artery disease
Nitroglycerin , Isosorbid Dinitrate , Isosorbid mononitrate , Nitroprusside (mechanism of action, pharmacological action, uses , side effects, precautions, D-D interactions...)
Mechanism of action:
- The coronary artery nourishes the heart muscle (it contracts with cold, so, for example, there are many clots in Russia due to the strong contractions that occur).
- When nitrates are given, it turns into nitric oxide, increasing its percentage in the body.
- After that, it turns into s-nitrosothiols when it enters the vascular smooth muscle by adding an SH group.
- It binds to the guanylyl cyclase cell membrane located on the smooth muscle .
- It is transformed by GTP into cGMP (cyclic guanosine monophosphate). The first thing is to remove the phosphate group on the myosin filaments and convert it from myosin light chain PO4, which was leading to binding to actin filaments and causing contraction in the coronary. The reason for the association was the presence of phosphorylation between the filaments.
- It is converted to myosin light chain by means of dephosphorylation, this process leads to coronary dilation, thus dilating the artery and increasing the blood flow .
Pharmacological action:
- The demand for oxygen is reduced. This leads to a reduction in symptoms.
- The preload decreases.
- Increase the amount of blood that goes to the heart.
Uses:
- Effective in the case of stable or atypical angina and very rarely effective in cases of unstable angina.
- Reducing body pressure in general because an expansion process occurred.
- Treating heart failure to reduce preload.
Side effects:
- Because of the dilation, the patient will feel a headache , because pressure on the nerve in the head will lead to headache, facial flushing .
- redness.
- reflexes tachycardia .
Drug - drug interactions
Nitrates should not be given with sildenafil combination medicine, because nitrates will destroy the enzyme responsible for breaking down sildenafil, thus increasing its toxicity and blood ratio, leading to severe hypotension.
Precautions:
- To prevent the occurrence of tolerance, the patient should stop for 10-12 hours to restore the body's response to the drug .
- People usually have the crisis in the morning because the epinephrine, norepinephrine, and dopamine are released in the morning, so it is preferable to give the medicine in the evening before bedtime, so that the morning is in a good condition, and it prevents taking this chacholamine and feels comfortable in the morning.