Anti-thyroid Drugs: Precautions in Pregnancy, Lactation and Asthma

The thyroid gland of our body controls the body metabolism through its iodine containing hormones. Normal thyroid gland is not palpable but the enlarged thyroid gland could be felt in front of the neck and may be associated with non-toxic or toxic goitre. Goitrous gland may have normal function or under function (hypothyroidism) or over function hyperthyroidism). The exophthalmic goitre is known as Graves's disease and in this
disease the eye balls protrude due to thyrotoxicosis.

The compounds used as anti-thyroid drugs include carbimazole and propylthiouracil. Anti-thyroid drugs inhibit the formation of thyroxine and triiodothyronine (T3) in the thyroid gland. Propylthiouracil also retard the peripheral conversion of thyroxine into triiodothyronine (T3). The same drugs are also used for the treatment of thyrotoxicosis and preparation for thyroidectomy. Anti-thyroid drugs may suppress the bone marrow so blood cell counts are advisable at regular intervals during the course of treatment. Pregnant and/or lactating patients with thyrotoxicosis need to consult the endocrinologist and to reduce the dose to minimum. Patients with tracheal obstruction or asthma also need extra care during the treatment of hyperthyroidism or thyrotoxicosis. Anti-thyroid drugs may cause nausea, gastro-intestinal upset, thyroid enlargement, agranulocytosis, granulocytopenia ( low count of neutrophils and eosinophils), leucopenia (low count of white blood cells) and thrombocytopenia low count of platelets); that is why regular blood counts are advisable. Self-treatment of hyperthyroidism or thyrotoxicosis is not advisable, as it needs investigative follow up. However, carbimazole oral drug is started with a dose of 15-45mg daily in divided doses depending on the severity of the disease and maintenance dose could be 2.5-25mg daily for 12 months. For thyroidectomy preparation, the dose may be 15-45mg daily in divided doses for 2-4 weeks depending on the severity of the disease.

To know more about thyroid gland and its functions-click here: http://ntips4u.blogspot.com/2009/07/thyroid-gland-and-its-functions.html

 

Thyroid Drugs: Precautions in Diabetes and Heart Disease

Thyroid drugs are used for treatment of hypothyroidism a condition caused by under function of thyroid gland. These drugs are based on thyroid extract and increase the metabolic rate with a subsequent increase in catabolism. Thyroid gland is associated with the general metabolism of all body tissues. Suboptimal activity of thyroid gland at birth leads to hypo-secretion of thyroid hormones and causes cretinism, impairing the mental and physical growth of an infant or child. The child grows up a mentally retarded dwarf, unless diagnosed and treated with thyroid drugs. Patients affected by under function of thyroid gland or hypothyroidism, develop generalized oedema called myxoedema (swelling of body). In myxoedema metabolic processes slow down with a tendency to gain weight. There is slowness of mind and speech and one feels lethargic.

Thyroid drugs used for hypothyroidism as well as cretinism contain thyroglobulin, thyroxine or liothyronine. Same drugs are also used for thyroid replacement therapy in cases of thyroidectomy. Treatment is started with low initial dose of 50-100 mcg daily, increased 25-50mcg at 3-4 weeks interval and maintenance dose may be 200-300mcg.
Overdosage or too rapid increase may produce signs and symptoms of hyperthyroidism, so self-treatment of hypothyroidism is not advisable. Patients receiving diabetic treatment, anticoagulant therapy, corticosteroid therapy or anti-hypertension therapy may need readjustment of treatment. There are many side effects of thyroid drugs. Patients receiving treatment for hypothyroidism, myxoedema, or cretinism may feel restlessness and have headache, transient diarrhoea, weight loss, anginal pain and palpitations. Overdosage of thyroid drugs in patients with heart disease may lead to serious complications.

To know more about thyroidisms click here: http://ntips4u.blogspot.com/2009/07/signs-and-symptoms-of-thyroid-disorders.html

Management of Hyperlipidemia

Elevated levels of fatty components in our blood is termed as hyperlipidemia. It is considered as a primary risk factor for coronary heart disease (CHD), stroke and peripheral vascular disease irrespective of the gender of a patient. Hyperlipidemia may complicate the health status in association with the diabetes, hypertension and kidney disease. There exists a strong association between the total cholesterol level and CHD. The cholesterol homeostasis is maintained by the liver and small intestine through very delicate balance of cholesterol input (dietary intake and de-novo synthesis of cholesterol) and elimination by conversion to bile and through fecal excretion. In the liver cells (hepatocytes) low density lipoprotein cholesterol (LDL-C) is produced through the conversion of HMG-Coenzyme-A (HMG-CoA) to mevalonic acid. It is important to note that LDL-C is a bad lipid whereas HDL-C is good. There is need to keep a check on the level of cholesterol in general and LDL-C in particular.

Cardiovascular morbidity and mortality is directly associated with the level of total cholesterol and LDL-C, and inversely with the level of high density lipoprotein cholesterol HDL-C). Cholesterol-enriched and triglyceride-rich lipoproteins, including very low density lipoproteins (VLDL) and intermediate density lipoproteins ((IDL) could also promote atherosclerosis. The elevated level of LDL-C warrants the need of cholesterol lowering therapy, inclusive of life style modification and cholesterol lowering drugs. HMG-CoA reductase inhibitor or statins are the most potent and widely used drugs for treating hypercholesterolemia or hyperlipidemia because of their efficacy in reducing LDL-C to the desired level as recommended by the National Cholesterol Education Program (NCEP). For effective control of hyperlipidemia around 20-55% reduction in the level of LDL-C needs to be achieved by Statins. The hyperlipidemia may be primary (heterozygous familial or non-familial hyperlipidemia) or secondary to some other disorder like renal disease. It has been established now that ezetimibe as monotherapy in association with customized diet, effectively reduces the elevated level of total cholesterol, LDL-C, Apo-B and triglycerides, and increases the level of HDL-C in patients with hypercholesterolemia. Ezetimibe is a selective cholesterol absorption inhibitor and was approved by FDA about 8 years ago. Statins (atorvastatin, lovastatin, pravastatin and simvastatin) are potent, HMG-CoA reductase inhibitors. The combination of ezetimibe and atorvastatin or simvastatin is effective therapy for taming down the elevated levels of total cholesterol and LDL-C in patients with homozygous familial hypercholesterolemia (HoFH). The treatment of hyperlipidemia should be commenced under medical advice and follow-up with biochemical evaluation of lipids in blood.

Important tip: Kill the fat before it kills you.

Post Exposure Prophylaxis Therapy for HIV

The impact of exposure to human immunodeficiency virus (HIV) depends on two main factors: (1) Nature of exposure and (2) The status of the source patient (the patient to whose blood or body fluids exposure has occurred). There is need to evaluate the source patient within 2 hours of exposure so that post exposure prophylaxis (PEP) could be started. The initiation of PEP should not be delayed more than 72 hours in any case. The baseline HIV testing should also be done for the exposed person before starting post exposure prophylaxis therapy. The post exposure prophylaxis refers to the comprehensive management given to the exposed person to minimize the risk of infection following potential exposure to blood-borne viruses (HIV, HBV and HCV). The risk assessment could only be evaluated through relevant laboratory investigations. Antiretroviral therapy should be started after consultation with the physician and follow up and supportive counseling should be provided to the exposed person at the surveillance centers.

The relative risk of HIV transmission after different routes of exposure has been established as under:

Exposure Route	HIV Transmission
Blood transfusion	90-95%
Sexual intercourse-Vaginal	1-10%
Sexual intercourse-anal	0.05-0.5%
Sexual intercourse-oral	0.005-0.01%
Perinatal	20-40%
Intravenous drug use	0.5-1%
Needle stick injury	0.5%
Mucous membrane splash to eyes	0.1%

The exposure to blood, semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid and amniotic fluid is considered risky and infectious. However, exposure to tears, sweat, urine, faeces and saliva is not considered infectious unless these secretions contain blood. The exposure is considered mild if the contact is with the eyes or mucous membranes or there is needle stick injury with small bore needle generally during vaccination or skin testing. The exposure is considered moderate if the mucous membranes or intact skin is exposed to large volume of body fluid or blood of the infected patient. A cut with surgical blade or needle stick injury with blood smeared needle. The exposure is considered severe if the accidental prick is with high bore (> 18G) needle contaminated with blood or a deep wound is caused with surgical knife smeared with blood. Transfusion of infected blood or packed cells.

The prescription of post exposure prophylaxis depends on the category of exposure. For mild exposure, basic regimen or 2-drug combination is generally prescribed depending on the status of the source of exposure. If the exposure source is HIV+ but asymptomatic, consider 2-drug PEP and if the source is HIV+ and clinically symptomatic, immediately start 2-drug PEP. In case of moderate exposure to HIV+ but asymptomatic source, start 2-drug PEP. If the source is found HIV+ and clinically symptomatic in case of moderate exposure, start expanded regimen which is 3-drug combination. In case of severe exposure to an HIV+ but asymptomatic or clinically symptomatic source, immediately start 3-drug combination. PEP regimens prescribed by health centers are: (1) 2-drug regimen: Zidovudine (AZT) + Lamivudine (3TC) or Stavudine (d4T) + Lamivudine (3TC). (2) 3-drug regimen: Zidovudine (AZT) + Stavudine (d4T) + Lamivudine (3TC). Expert opinion is must before starting PEP therapy.

Antimicrobial Agents and Drug Resistant Bacteria

There are about a dozen antimicrobial agents (AMA) and an equal number of bacterial types or species which are resistant to one or the other afore said antimicrobial agent or antibiotic. A list of these antimicrobial agents or antibiotics and corresponding resistant bacteria has been cited in the table-1 below. Antimicrobial susceptibility testing (AMST) against these antimicrobial agents or antibiotics with reference to corresponding bacteria could be discontinued to save time and money.

Table-1: Antimicrobial agents or antibiotics and resistant bacteria

Antimicrobial agent	Resistant Bacteria
Aminoglycosides	Anaerobic bacteria, Enterococci and Streptococci
Ampicillin	Klebsiella species
Aztreonam	Gram-positive bacteria
Vancomycin	Gram-negative bacteria
Sulphonamides, trimethoprim	Proteus aeruginosa
Tetracycline, chloramphenicol	P. aeruginosa
All cephalosporins	Enterococci
Aminoglycosides	Enterococci
Imipenem	Stenotrophomonas maltophilia
Metronidazole	Aerobic bacteria