The prescription of drugs to a pregnant woman is a balance between possible adverse drug effects on the fetus and the risk to mother and fetus of leaving maternal disease inadequately treated. Effects on the human fetus cannot be reliably predicted from animal studies – hence one should prescribe drugs for which there is experience of safety over many years in preference to new or untried drugs. The smallest effective dose should be used. The fetus is most sensitive to adverse drug effects during the first trimester. It has been estimated that nearly half of all pregnancies in the UK are unplanned, and that most women do not present to a doctor until five to seven weeks after conception. Thus, sexually active women of childbearing potential should be assumed to be pregnant until it has been proved otherwise.
Delayed toxicity is a sinister problem (e.g. diethylstilbestrol) and if the teratogenic effect of thalidomide had not produced such an unusual congenital abnormality, namely phocomelia, its detection might have been delayed further. If drugs (or envi-ronmental toxins) have more subtle effects on the fetus (e.g. a minor reduction in intelligence) or cause an increased incidence of a common disease (e.g. atopy), these effects may never be detected. Many publications demand careful prospective controlled clinical trials, but the ethics and practicalities of such studies often make their demands unrealistic. A more rational approach is for drug regulatory bodies, the pharmaceutical industry and drug information agencies to collaborate closely and internationally to collate all information concerning drug use in pregnancy (whether inadvertent or planned) and associate these with outcome. This will require significant investment of time and money, as well as considerable encouragement to doctors and midwives to complete the endless forms.
Saturday, July 9, 2011
DRUGS IN PREGNANCY
The use of drugs in pregnancy is complicated by the potential for harmful effects on the growing fetus, altered maternal physiology and the paucity and difficulties of research in this field.
There is potential for harmful effects on the growing fetus.
Because of human variation, subtle effects to the fetus may be virtually impossible to identify.
There is altered maternal physiology.
There is notable paucity of and difficulties in research in this area.
HARMFUL EFFECTS ON THE FETUS
Because experience with many drugs in pregnancy is severely limited, it should be assumed that all drugs are potentially harmful until sufficient data exist to indicate otherwise. ‘Social’
drugs (alcohol and cigarette smoking) are definitely damaging and their use must be discouraged.
In the placenta, maternal blood is separated from fetal blood by a cellular membrane. Most drugs with a molecular weight of less than 1000 can cross the placenta. This is usually by passive diffusion down the concentration gradient, but can involve active transport. The rate of diffusion depends first on the concentration of free drug (i.e. non-protein bound) on each side of the membrane, and second on the lipid solubility of the drug, which is determined in part by the degree of ionization. Diffusion occurs if the drug is in the unionized state. Placental function is also modified by changes in blood flow, and drugs which reduce placental blood flow can reduce birth weight. This may be the mechanism which causes the small reduction in birth weight following treatment of the mother with atenolol in pregnancy. Early in embryonic development, exogenous substances accumulate in the neuro-ectoderm. The fetal blood–brain barrier is not developed until the second half of pregnancy, and the susceptibility of the cen-
tral nervous system (CNS) to developmental toxins may be partly related to this. The human placenta possesses multiple enzymes that are primarily involved with endogenous steroid
metabolism, but which may also contribute to drug metabolism and clearance.
The stage of gestation influences the effects of drugs on the fetus. It is convenient to divide pregnancy into four stages, namely fertilization and implantation (Ͻ17 days), the organogenesis/embryonic stage (17–57 days), the fetogenic stage and delivery.
FERTILIZATION AND IMPLANTATION
Animal studies suggest that interference with the fetus before 17 days gestation causes abortion, i.e. if pregnancy continues the fetus is unharmed.
ORGANOGENESIS/EMBRYONIC STAGE
At this stage, the fetus is differentiating to form major organs, and this is the critical period for teratogenesis. Teratogens cause deviations or abnormalities in the development of the embryo that are compatible with prenatal life and are observable postnatally. Drugs that interfere with this process can cause gross structural defects (e.g. thalidomide phocomelia).
Some drugs are confirmed teratogens, but for many the evidence is inconclusive. Thalidomide was unusual in the way in which a very small dose of the drug given on only one or two occasions between the fourth and seventh weeks of pregnancy predictably produced serious malformations.
DELIVERY
Some drugs given late in pregnancy or during delivery may cause particular problems. Pethidine, administered as an analgesic can cause fetal apnoea (which is reversed with naloxone). Anaesthetic agents given during Caesarean section may transiently depress neurological, respiratory and muscular functions. Warfarin given in late pregnancy causes a haemostasis defect in the baby, and predisposes to cerebral haemorrhage during delivery.
There is potential for harmful effects on the growing fetus.
Because of human variation, subtle effects to the fetus may be virtually impossible to identify.
There is altered maternal physiology.
There is notable paucity of and difficulties in research in this area.
HARMFUL EFFECTS ON THE FETUS
Because experience with many drugs in pregnancy is severely limited, it should be assumed that all drugs are potentially harmful until sufficient data exist to indicate otherwise. ‘Social’
drugs (alcohol and cigarette smoking) are definitely damaging and their use must be discouraged.
In the placenta, maternal blood is separated from fetal blood by a cellular membrane. Most drugs with a molecular weight of less than 1000 can cross the placenta. This is usually by passive diffusion down the concentration gradient, but can involve active transport. The rate of diffusion depends first on the concentration of free drug (i.e. non-protein bound) on each side of the membrane, and second on the lipid solubility of the drug, which is determined in part by the degree of ionization. Diffusion occurs if the drug is in the unionized state. Placental function is also modified by changes in blood flow, and drugs which reduce placental blood flow can reduce birth weight. This may be the mechanism which causes the small reduction in birth weight following treatment of the mother with atenolol in pregnancy. Early in embryonic development, exogenous substances accumulate in the neuro-ectoderm. The fetal blood–brain barrier is not developed until the second half of pregnancy, and the susceptibility of the cen-
tral nervous system (CNS) to developmental toxins may be partly related to this. The human placenta possesses multiple enzymes that are primarily involved with endogenous steroid
metabolism, but which may also contribute to drug metabolism and clearance.
The stage of gestation influences the effects of drugs on the fetus. It is convenient to divide pregnancy into four stages, namely fertilization and implantation (Ͻ17 days), the organogenesis/embryonic stage (17–57 days), the fetogenic stage and delivery.
FERTILIZATION AND IMPLANTATION
Animal studies suggest that interference with the fetus before 17 days gestation causes abortion, i.e. if pregnancy continues the fetus is unharmed.
ORGANOGENESIS/EMBRYONIC STAGE
At this stage, the fetus is differentiating to form major organs, and this is the critical period for teratogenesis. Teratogens cause deviations or abnormalities in the development of the embryo that are compatible with prenatal life and are observable postnatally. Drugs that interfere with this process can cause gross structural defects (e.g. thalidomide phocomelia).
Some drugs are confirmed teratogens, but for many the evidence is inconclusive. Thalidomide was unusual in the way in which a very small dose of the drug given on only one or two occasions between the fourth and seventh weeks of pregnancy predictably produced serious malformations.
DELIVERY
Some drugs given late in pregnancy or during delivery may cause particular problems. Pethidine, administered as an analgesic can cause fetal apnoea (which is reversed with naloxone). Anaesthetic agents given during Caesarean section may transiently depress neurological, respiratory and muscular functions. Warfarin given in late pregnancy causes a haemostasis defect in the baby, and predisposes to cerebral haemorrhage during delivery.
Wednesday, May 11, 2011
TITRIMETRIC ANALYSIS OF CHLORIDE
Introduction
The purpose of this experiment is to compare two titrimetric methods for the analysis of chloride in a water-soluble solid. The two methods are:
• a weight titration method using a chemical indicator;
• a volumetric titration method using potentiometric detection.
The most important difference between the methods is how the endpoint is determined. In the first case, the color change of the indicator signifies that the titration is complete, while the second method generates a titration curve from which the endpoint is determined. For the potentiometric method, an automatic titrator will be used to perform the titration, and to obtain the titration curve.
Background
Argentometric Titrations
In order for a titrimetric method to be viable, the titration reaction
(1) must be complete (i.e., Ktitration is large) and
(2) should be rapid.
There are many precipitation reactions that can satisfy the first requirement, but far fewer that satisfy the second. Precipitation reactions of silver salts are usually quite rapid, and so argentometric titrations, which use AgNO3 as the titrant, are the most common precipitation titrations.
Argentometric titrations can be used to analyze samples for the presence of a number of anions that form precipitates with Ag+
Weight Titrations The goal of any titrimetric method is to determine the number of moles of titrant needed to reach the equivalence point of the titration reaction:
titration reaction aA + tT → product(s)
where a and t are the stoichiometric coefficients in the reaction between titrant and analyte. In a titrimetric analysis, solution of titrant is added until the equivalence point of the titration reaction is reached. At the equivalence point, neither analyte nor titrant is present in excess. By definition, the equivalence point is the point during the titration at which the following relationship is true: equivalence point
nA/a = nT/t
where nA is the number of moles of analyte originally present in the sample solution, and nT is the number of moles of titrant that must be added to the sample to reach the equivalence point.
From this last expression, we see that, in order to determine the number of moles of analyte originally present in the sample solution, we must
(a) know the stoichiometry of the reaction, and
(b) determine how many moles of titrant are needed to reach the endpoint. In order to meet this last requirement, we must somehow keep track of the quantity of titrant solution that is added to the sample solution.
The purpose of this experiment is to compare two titrimetric methods for the analysis of chloride in a water-soluble solid. The two methods are:
• a weight titration method using a chemical indicator;
• a volumetric titration method using potentiometric detection.
The most important difference between the methods is how the endpoint is determined. In the first case, the color change of the indicator signifies that the titration is complete, while the second method generates a titration curve from which the endpoint is determined. For the potentiometric method, an automatic titrator will be used to perform the titration, and to obtain the titration curve.
Background
Argentometric Titrations
In order for a titrimetric method to be viable, the titration reaction
(1) must be complete (i.e., Ktitration is large) and
(2) should be rapid.
There are many precipitation reactions that can satisfy the first requirement, but far fewer that satisfy the second. Precipitation reactions of silver salts are usually quite rapid, and so argentometric titrations, which use AgNO3 as the titrant, are the most common precipitation titrations.
Argentometric titrations can be used to analyze samples for the presence of a number of anions that form precipitates with Ag+
Weight Titrations The goal of any titrimetric method is to determine the number of moles of titrant needed to reach the equivalence point of the titration reaction:
titration reaction aA + tT → product(s)
where a and t are the stoichiometric coefficients in the reaction between titrant and analyte. In a titrimetric analysis, solution of titrant is added until the equivalence point of the titration reaction is reached. At the equivalence point, neither analyte nor titrant is present in excess. By definition, the equivalence point is the point during the titration at which the following relationship is true: equivalence point
nA/a = nT/t
where nA is the number of moles of analyte originally present in the sample solution, and nT is the number of moles of titrant that must be added to the sample to reach the equivalence point.
From this last expression, we see that, in order to determine the number of moles of analyte originally present in the sample solution, we must
(a) know the stoichiometry of the reaction, and
(b) determine how many moles of titrant are needed to reach the endpoint. In order to meet this last requirement, we must somehow keep track of the quantity of titrant solution that is added to the sample solution.
Monday, April 11, 2011
Diabetes helpful Nutrition
In regards to diabetics, consuming the appropriate foods is indispensable for sustaining optimum health. Not only would you have to think about the nutrition your own body desires, you've also got to account for how foods will influence your blood sugar levels. Listed here are a small number of aspects to consider when you are scheduling your daily food lists.
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It's recommended that people with diabetes follow the Diabetes Food Pyramid, which is for use with the USDA's Food Pyramid. Those who follow the Diabetic Food Pyramid can then pick up plenty of the nutrients, protein, fiber, carbohydrates, and fats that the body requires to optimize blood sugar levels and nutrition.
After you have established a base amount, then it is possible to determine what is nourishing for a diabetic. Generally 100-150 day by day is enough. Around 30 in the morning; 45 at lunch; and maybe 45 at dinner; everybody is different so talk to your nutritionist for further details. In your mission to better nourishment you must also imagine what forms of food to eat. A lot of people usually do not recognize that natural sugars trigger elevated sugar levels also?
A good dietary and dietetic planning is very necessary for diabetes. One should chalk out a meal chart and follow it religiously. Increasing the consumption of starchy veggies, cereals like black beans, garbanzo beans and breads are advisable.
The best way to keep your diabetes under control is by eating small amounts of sugar.It is also a good idea to have a mix of carbohydrates, fats and proteins at each meal.
Most of the sugar that the body uses to convert to energy will come from the carbohydrates that are consumed so this food group ought to be monitored. A plan will specify the portions of carbohydrates and the number of portions that can be consumed in one sitting.
A further part of diabetic nourishment is to eat on a normal basis. This means that your blood sugar analysis is going to be steady always. Diabetic nourishment isn't so much based on restricting the amount of sugar that the body will get but in what manner and what kind of foods can offer the sugar that our bodies really need to generate energy. Specifically, remember to maintain recurring appointments with your general practitioner. Your health practitioner is your best source of advice and information in relation to your situation and your dietitian is your ideal source of info in relation to the foods which you should be eating.
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http://390d07-hy4w5jq4ovwo5jz-wdu.hop.clickbank.net/
It's recommended that people with diabetes follow the Diabetes Food Pyramid, which is for use with the USDA's Food Pyramid. Those who follow the Diabetic Food Pyramid can then pick up plenty of the nutrients, protein, fiber, carbohydrates, and fats that the body requires to optimize blood sugar levels and nutrition.
After you have established a base amount, then it is possible to determine what is nourishing for a diabetic. Generally 100-150 day by day is enough. Around 30 in the morning; 45 at lunch; and maybe 45 at dinner; everybody is different so talk to your nutritionist for further details. In your mission to better nourishment you must also imagine what forms of food to eat. A lot of people usually do not recognize that natural sugars trigger elevated sugar levels also?
A good dietary and dietetic planning is very necessary for diabetes. One should chalk out a meal chart and follow it religiously. Increasing the consumption of starchy veggies, cereals like black beans, garbanzo beans and breads are advisable.
The best way to keep your diabetes under control is by eating small amounts of sugar.It is also a good idea to have a mix of carbohydrates, fats and proteins at each meal.
Most of the sugar that the body uses to convert to energy will come from the carbohydrates that are consumed so this food group ought to be monitored. A plan will specify the portions of carbohydrates and the number of portions that can be consumed in one sitting.
A further part of diabetic nourishment is to eat on a normal basis. This means that your blood sugar analysis is going to be steady always. Diabetic nourishment isn't so much based on restricting the amount of sugar that the body will get but in what manner and what kind of foods can offer the sugar that our bodies really need to generate energy. Specifically, remember to maintain recurring appointments with your general practitioner. Your health practitioner is your best source of advice and information in relation to your situation and your dietitian is your ideal source of info in relation to the foods which you should be eating.
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Tuesday, April 5, 2011
A Popular Drug For Chemotherapy: Alimta
Did you know that chemotherapy is not effective in all types of cancers? In some cases it is quite unnecessary and useless. Alimta for chemotherapy has been approved by the US Food and Drug Administration (FDA) for the treatment of non-small cell lung cancer and pleural mesothelioma. The drug is a popular brand of a chemotherapy drug called Pemetrexed. The manufacturer and marketer of this brand is Eli Lilly and Company.
Alimta: Chemotherapy Precautions
Any type of chemotherapy will have certain side effects. Same happens in case of chemotherapy with Alimta Pemetrxed. However, certain precautions can and should be taken in order to minimize these reactions and ensure the best possible treatment.
some of these precautions:
Talk to your doctor candidly: You should be very open with your doctor and tell him about any other diseases you might be suffering from. You must talk to your healthcare provider about pleural effusion, ascites, any allergies you might be suffering from and kidney diseases. It is important that your doctor knows if you are pregnant or planning to get pregnant or recently had a baby and are now breastfeeding. Additionally, you must make ensure that you are not allergic to any of the ingredients of Alimta. In case you are on some medication, vitamins or herbal supplements, it is important that you tell your doctor about it. Prescription or non prescription, your health care provider must know about it.
Take Vitamin B12: You can minimize most of the side effects of chemotherapy with Alimta by taking Vitamin B12 along with the process. However, you must ask your doctor about it first and take the vitamin tablets only if he recommends.
Alimta: Chemotherapy Warnings
Before you begin your chemotherapy with Alimta, you must be aware of a few things. Not everyone's body reacts the same way to chemotherapy with this drug. Hence, you must have a thorough discussion with your doctor to know the things to expect.
Sometimes chemotherapy can reduce your blood count. If it reduces your red blood cell count you might suffer from anemia and if it reduces your white blood cell count your immunity might decrease. This can be dangerous and even life threatening. In such a case, your doctor might have to reduce your dose or perhaps delay the next dosage.
Alimta could also cause some skin rashes or other similar problems. For this, your doctor might recommend corticosteroid in order to reduce this side effect.
This chemotherapy drug could also interact with other medicines you might be taking. Hence, your doctor will have to know what all you are on and how it might affect the process. You might or might not have to discontinue with other medication.
http://390d07-hy4w5jq4ovwo5jz-wdu.hop.clickbank.net/
Alimta: Chemotherapy Precautions
Any type of chemotherapy will have certain side effects. Same happens in case of chemotherapy with Alimta Pemetrxed. However, certain precautions can and should be taken in order to minimize these reactions and ensure the best possible treatment.
some of these precautions:
Talk to your doctor candidly: You should be very open with your doctor and tell him about any other diseases you might be suffering from. You must talk to your healthcare provider about pleural effusion, ascites, any allergies you might be suffering from and kidney diseases. It is important that your doctor knows if you are pregnant or planning to get pregnant or recently had a baby and are now breastfeeding. Additionally, you must make ensure that you are not allergic to any of the ingredients of Alimta. In case you are on some medication, vitamins or herbal supplements, it is important that you tell your doctor about it. Prescription or non prescription, your health care provider must know about it.
Take Vitamin B12: You can minimize most of the side effects of chemotherapy with Alimta by taking Vitamin B12 along with the process. However, you must ask your doctor about it first and take the vitamin tablets only if he recommends.
Alimta: Chemotherapy Warnings
Before you begin your chemotherapy with Alimta, you must be aware of a few things. Not everyone's body reacts the same way to chemotherapy with this drug. Hence, you must have a thorough discussion with your doctor to know the things to expect.
Sometimes chemotherapy can reduce your blood count. If it reduces your red blood cell count you might suffer from anemia and if it reduces your white blood cell count your immunity might decrease. This can be dangerous and even life threatening. In such a case, your doctor might have to reduce your dose or perhaps delay the next dosage.
Alimta could also cause some skin rashes or other similar problems. For this, your doctor might recommend corticosteroid in order to reduce this side effect.
This chemotherapy drug could also interact with other medicines you might be taking. Hence, your doctor will have to know what all you are on and how it might affect the process. You might or might not have to discontinue with other medication.
http://390d07-hy4w5jq4ovwo5jz-wdu.hop.clickbank.net/
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