Suxamethonium has a longer duration of effect than acetylcholine, and is not hydrolyzed by acetylcholinesterase. By maintaining the membrane potential above threshold, it does not allow the muscle cell to repolarize. When acetylcholine binds to an already depolarized receptor, it cannot cause further depolarization. Calcium is removed from the muscle cell cytoplasm independent of repolarization (depolarization signaling and muscle contraction are independent processes). As the calcium is taken up by the sarcoplasmic reticulum, the muscle relaxes. This explains muscle flaccidity rather than tetany following fasciculations. The results are membrane depolarization and transient fasciculations, followed by paralysis. Phase 2 block
While this phase is not abnormal and is a part of its mechanism of action, it is undesirable during surgery, due to the inability to depolarize the cell again. Often, patients must be on a ventilator for hours if Phase 2 block occurs. It is caused by the blood concentration of suxamethonium exceeding the therapeutic window. Desensitization occurs at the nerve terminal, and the myocyte becomes less sensitive to acetylcholine; the membrane repolarizes and cannot be depolarized again. Chemistry
Suxamethonium is an odorless, white crystalline substance. Aqueous solutions have a pH of about 4. The dihydrate melts at 160 °C, whereas the anhydrous melts at 190 °C. It is highly soluble in water (1 gram in about 1 mL), soluble in ethyl alcohol (1 gram in about 350 mL), slightly soluble in chloroform, and practically insoluble in ether. Suxamethonium is a hygroscopic compound. The compound consists of two acetylcholine molecules that are linked by their acetyl groups.
Brolucizumab (sold, depending on part of the world, under trade names Beovu or Vsiqq), is a humanized single-chain antibody fragment for the treatment of neovascular (wet) age-related macular degeneration (AMD).The most common side effects are reduced visual acuity, cataract (clouding of the lens in the eye), conjunctival haemorrhage (bleeding at the front of the eye) and vitreous floaters (spots in the vision). The most serious side effects are blindness, endophthalmitis (an infection inside the eye), retinal artery occlusion (blockage of the artery in the retina) and retinal detachment (separation of the retina from the back of the eye).Brolucizumab was designed to attach to and block a substance called vascular endothelial growth factor A (VEGF-A). VEGF-A is a protein that makes blood vessels grow and leak fluid and blood, damaging the macula. By blocking VEGF-A, brolucizumab reduces the growth of the blood vessels and controls the leakage and swelling. History
This drug was developed by ESBATech (discovery to phase 2a), Alcon Laboratories (phase 2b), and Novartis (phase 3).Brolucizumab is U.S. Food and Drug Administration (FDA) approved in ophthalmology as Beovu.Brolucizumab successfully completed phase III development in wet age-related macular degeneration (AMD) meeting the primary efficacy endpoint of non-inferiority to aflibercept in mean change in best corrected visual acuity (BCVA) from baseline to week 48.