state the use and route of administration of insulin
Answers
routes of administration of insulin
By Injection:
Intravenous insulin is used in hospitals for emergency situations, post-operative management and so forth. Only soluble insulin should be used. The advantage is that it allows very rapid adjustment to changes in blood glucose. The potential disadvantage is that the metabolic situation can deteriorate very rapidly once iv insulin is discontinued. Intravenous insulin is unsuitable for long-term use owing to the difficulty of continuous administration and increased risk of infection or thrombosis.
Subcutaneous insulin is the standard route of administration, suitable for both short and long-acting insulins. The advantages are convenience, reliability, and (as compared with iv insulin) the persistence of residual insulin under the skin, which offers some protection against rapid swings in glucose control. The disadvantages are (1) delayed and somewhat erratic absorption into the circulation (there are no truly "peakless" insulins), and (2) the insulin is administered into the systemic circulation, whereas truly physiologic replacement would be into the portal circulation.
Jet spray injectors avoid the need for use of a needle but are not pain-free; few people have opted for this means of administration.
Intraperitoneal insulin is absorbed into the portal circulation, and thus offers advantages as compared with subcutaneous insulin. It can be used in patients with renal failure treated with continuous intraperitoneal dialysis (CAPD), when it is added to the dialysis fluid. It is also used, albeit rarely, in continuous intraperitoneal insulin infusion therapy; see CIPII Intraperitoneal insulin
Other Routes of Administration
Nasal Insulin: Nasal insulin administration was actively investigated in the 1970s and 1980s, and appeared to offer the advantage of very rapid insulin delivery into the circulation coupled with the avoidance of pre-meal insulin injections. Unfortunately the problems of low bioavailability and variable absorption have limited commercial interest in this approach.
Inhaled insulin. As with intranasal insulin, Inhaled insulin potentially offers rapid absorption of needle-free insulin. The lung has a surface area of ~100 m2, and small molecules such as insulin (molecular mass 5700, diameter 2.2 nm) are readily absorbed via the alveoli. Pfizer launched an inhaled insulin under the trade name of Exubera in 2006 but withdrew it in 2008, citing poor demand.
Problems included poor bioavailability, (much of the inhaled insulin is lost in the "dead space" of the bronchial tree), and associated high costs. The inhaler proved bulky and inconvenient. Furthermore, use of inhaled insulin was associated with evidence of a mild induced restrictive lung defect[1]. A greater concern was that 6/4,740 patients on Exubera developed lung cancer during the trial, as against 1/4,292 in the comparison group.
Despite this unpromising prologue, the FDA gave its approval for clinical use of Afrezza, a new formulation of inhaled insulin developed by MannKind [2].
Oral Insulin: Insulin, being a peptide chain, is rapidly broken down by acids in the stomach or digested by proteolytic enzymes. Many attempts have been made to deliver insulin in a form capable of bypassing the stomach, including liposomes, capsules and nanoparticles[3]. Low and erratic bioavailability remain major problems, and the utility of this approach remains to be demonstrated. See Oral insulin