Emulsions were said to be even more unreliable.Macrocrystalline aqueous suspensions of progesterone as well as microspheres of progesterone were investigated as potential progestogen-only injectable contraceptives and combined injectable contraceptives (with estradiol) by the late 1980s and early 1990s but were never marketed.Aqueous solutions of water-insoluble steroids were first developed via association with colloid solubility enhancers in the 1940s. An aqueous solution of progesterone for use by intravenous injection was marketed by Schering AG under the brand name Primolut Intravenous by 1962. One of its intended uses was the treatment of threatened abortion, in which rapid-acting effect was desirable. An aqueous solution of progesterone complexed with cyclodextrin to increase its water solubility was introduced for use by once-daily subcutaneous injection in Europe under the brand name Prolutex in the mid-2010s.In the 1950s, long-acting parenteral progestins such as hydroxyprogesterone caproate, medroxyprogesterone acetate, and norethisterone enanthate were developed and introduced for use by intramuscular injection. They lacked the need for frequent injections and the injection site reactions associated with progesterone by intramuscular injection and soon supplanted progesterone for parenteral therapy in most cases. Oral and sublingual
The first study of oral progesterone in humans was published in 1949. It found that oral progesterone produced significant progestational effects in the endometrium in women. Prior to this study, animal research had suggested that oral progesterone was inactive, and for this reason, oral progesterone had never been evaluated in humans. A variety of other early studies of oral progesterone in humans were also published in the 1950s and 1960s.
It is also important to note that because the degree of cortical reorganization is proportional to phantom limb pains, any perturbations to the amputated regions may increase pain perception. Mirror therapy
Mirror box therapy allows for illusions of movement and touch in a phantom limb by inducing somatosensory and motor pathway coupling between the phantom and real limb. Many patients experience pain as a result of a clenched phantom limb, and because phantom limbs are not under voluntary control, unclenching becomes impossible. This theory proposes that the phantom limb feels paralyzed because there is no feedback from the phantom back to the brain to inform it otherwise. Vilayanur S. Ramachandran believes that if the brain received visual feedback that the limb had moved, then the phantom limb would become unparalyzed.Although the use of mirror therapy has been shown to be effective in some cases there is still no widely accepted theory of how it works. According to 2017 paper that reviewed a wide range of studies of mirror therapy, "Research evidence suggests that a course of treatment (four weeks) of mirror therapy may reduce chronic pain. Contraindications and side effects are few. The mechanism of action of mirror therapy remains uncertain, with reintegration of motor and sensory systems, restored body image and control over fear-avoidance likely to influence outcome. The evidence for clinical efficacy of mirror therapy is encouraging, but not yet definitive. Nevertheless, mirror therapy is inexpensive, safe and easy for the patient to self-administer.