Thyroid System Medication

Levothyroxine (also marketed as Levoxyl, Levothroid, Synthroid, or L-thyroxine sodium) is the only thyroid system prescription that has recently featured prominently among the top 200 medications in the United States. Thus, 75.1 million, 80.7 million, and 79.4 million levothyroxine prescriptions were dispensed in 2003, 2004, and 2005, respectively. At these rates, levothyroxine by itself comprised 3.5, 2.9, and 3.4% of the total prescriptions in the top 200 most popular drugs in the United States in 2003, 2004, and 2005, respectively, making it the most prescribed drug. Levothyroxine is a synthetic version of the natural hormone thyroxine, which is released by the thyroid gland. The natural hormone is important in the development of fetuses and newborns, playing a role in cmcial processes such as the development 

Levothyroxine is taken orally or intravenously and is normally prescribed to treat hypothyroidism or to suppress the release of thyroid hormone so as to manage cancerous thyroid nodules (i.e., thyroid cancer) and growth of goiters. Other less frequently prescribed thyroid and parathyroid drugs include methimazole (Tapazole), various iodides, lithioronine (Triostat), and liotrix (Thyrolar). 

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As part of the standard prelithium workup, a thorough medical evaluation should be completed. Table 10-5 lists the various laboratory tests recommended to assess overall physical status, especially renal, thyroid, hematological, and cardiac function, before initiation of treatment. In particular, the renal and the thyroid systems require a baseline assessment and periodic reevaluation with maintenance or prophylactic lithium tnerapy. 

Substance-Induced Anxiety Disorder. Numerous medicines and drugs of abuse can produce panic attacks. Panic attacks can be triggered by central nervous system stimulants such as cocaine, methamphetamine, caffeine, over-the-counter herbal stimulants such as ephedra, or any of the medications commonly used to treat narcolepsy and ADHD, including psychostimulants and modafinil. Thyroid supplementation with thyroxine (Synthroid) or triiodothyronine (Cytomel) can rarely produce panic attacks. Abrupt withdrawal from central nervous system depressants such as alcohol, barbiturates, and benzodiazepines can cause panic attacks as well. This can be especially problematic with short-acting benzodiazepines such as alprazolam (Xanax), which is an effective treatment for panic disorder but which has been associated with between dose withdrawal symptoms. 

Medical history and a physical examination should be completed for every patient. Given the physiological changes during ECT, the physical examination should include assessment of the airway, cardiovascular, pulmonary, and central nervous systems. Eaboratory examinations may include a blood count, liver and thyroid function tests, urine analysis, and electrocardiogram (EKG). Other investigations such as skeletal X-ray, completed tomographic (CT) scan of the... 

Most attempts of using hormones as psychotropic medications were conducted with gonadal or with thyroid hormones, mainly because of the apparent mood changes associated with physiological or disorder-associated changes in levels or activity of these hormones. However, as shown in Table 17-1, current applications are broader and involve several hormones and systems. It is anticipated that, with acquired knowledge on mood effects of several other hormones, that list will continue to expand. Here, I focus on psychotropic effects of gonadal and thyroid hormones. Cortisol and melatonin are only briefly discussed. 

There is no such clear cut difTcrcnlialiun as metamorphosis in the mammal, but development is an extremely complex process and has been shown to depend upon the presence of adequate amounts of thyroid hormones. Deficient development, especially of the central nervous system, is marked in ehildren suffering from thyroid deficiency early in life, ansi this inadequacy cannot be overcome completely by medication commenced after the first few weeks. In the adult, thyroxine is important in the maintenance of energy turnover in most of the tissues of the body, such as the heart, skeletal muscle, liver, and kidney, Other physiological functions, most notably brain aclivity and reproduction, are also dependent upon thyroxine, although the metabolic rales of the tissues concerned in these functions do not seem to be altered. 

Because of the potential effect it may have on other body systems and the risk of toxicity, a baseline medical workup is de rigueur in every patient who is a candidate for lithium therapy. This workup includes laboratory tests aimed at evaluating kidney function, thyroid status, complete blood count, cardiac function, and so on. 

Another problem facing the diagnosis of depression or mania is the fact that other medical conditions can cause similar symptoms. Among them are illnesses such as thyroid diseases, infectious diseases (the flu), cancers of the central nervous system, neurological disorders (multiple sclerosis), blood diseases, and even some reactions to metal toxicity. 

FTY720 represents the first generation of LP receptor modulators that may have therapeutic value. Other data concerning the efficacy of FTY720 administration for the treatment of type I diabetes, uveoretinitis, thyroiditis, myocarditis, systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis in animal models have been reported (Fujino et al., 2003 Hozumi et al., 1999 Kurose et al., 2000 Matsuura et al., 2000 Okazaki et al., 2002 Suzuki et al., 1998 Webb et al., 2004). The potential to treat medically important diseases through LP receptor modulation represents an attractive and technically tractable approach that is being actively assessed. 

Compounds that are endocrine disrupters include natural animal hormones released into the environment, plant toxins or phytoestrogens, synthetic hormones present in sewage water and used for medical treatment (e.g., diethylstilbestrol), and several chemicals, including some pesticides and polychlorinated biphenols (PCBs). Endocrine disrupters enter the environment often as a by-product of many chemical and manufacturing processes and through waste disposal routes. Some evidence now suggests that effects of thyroid hormones and the immune system occur in addition to the disruptions of hormones that play a major part in the control of reproduction and development. 

Patients were registered as hyperthyroid if they had been treated for hyperthyroidism by surgery RAI or medication, or if they had a history of hyperthyroidism on the thyroid register. Patients on long-term thyroid replacement therapy according to the MEMO database were registered as hypothyroid. A validation of the database system was performed in 450 patients from general practice. A positive predictive value of 0.98 and 0.96 was found for treated hyperthyroidism and hypothyroidism, respectively. 

Medical Surveillance Preplacement and periodic evaluations should include a complete history with emphasis on the history of fainting spells that may be a result of a cardiovascular or a nervous disorder and also notations of those conditions that may create a susceptibility to the effects of anoxia or anemia. Physical examinations should emphasize the cardiovascular, nervous, and upper respiratory systems, along with the thyroid. Because cyanide is a defatting agent and can cause dermatitis on prolonged exposure, the skin should also be examined during these evaluations. 

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