Different people response in different ways to drug treatment. Taking the same drug, one person may suffer adverse affect while another experience none. however physician known that certain groups are always more at risk when they take drugs; The reason is that in those people the body handles drug differently, or special risk include infants and children, woman who are pregnant or breast feeding, The elderly and people with long term medical condition, especially those who are impaired liver or kidney function. Others who many need special attention include those already taking regular medication who may risk complication when they take another drug.
When physician prescribed drugs for special groups they take extra care to select appropriate medication, adjust dosage and closely monitor the effect of treatment. If you think you may at special risk, be sure to tell your physician in case she/he or not aware of your particular circumstances. Similarly if you are buying over the counter drugs you should ask your physician if you think you may be at risk from any possible adverse effect.
INFANTS AND CHILDREN
Infants and children need a lower dosage of drugs than adults because children have relatively low body weight. Moreover, because of differences in body composition, as well as the distribution and amount of body fat, and differences in the state of development and function organ such as the liver and kidneys at different ages, children cannot simply be given a proportion of an adult dose as if they were small adults. Dosage needs to be calculated in a more complex way, Taking account on both age and weight. although new born babies often have to be given very small doses of drugs. Older children may need relatively large doses of some drugs.
the liver enzyme system are not fully developed when a baby is born. This means that drugs are not broken down as rapidly as in an adult, and may become dangerously concentrated in the body, For this reason many drugs are prescribed for babies or are prescribed in very reduced doses. In older children, because the liver is relatively large compared to the rest of the body, Some drugs may need to be given in proportionately larger doses.
The kidneys During the first six month, a baby’s kidney are unable to excrete drugs as efficiently as those of an adult. This, too. may lead to a dangerously high concentration of a drug in a blood. The dose of certain drugs may therefore need to reduced. Between 1 or 2 years of age, Kidney function improves, and higher doses of some drugs may then needed.
Body Composition The proportion of water in the body of a premature baby is about 85% of its body weight, that of a full-term baby is 70%, and that of an adult is only 55%. This means that certain drugs are not as concentrated in an infants body as in adults, and higher doses relative to weight may need to be given initially.
Great care in needed during pregnancy to protect the fetus so that it develops into a healthy baby. Drugs taken by the mother can cross the placenta and enter’s the baby’s bloodstream. With certain drugs, and at a particular stages of pregnancy, there is a risk of developmental abnormalities, retarded growth, or post- delivery problem affecting baby, In addition, some drugs may affect the health of the mother during pregnancy.
Many drugs are known to have adverse effect during pregnancy; other are known to be safe, but in a large number of cases there is no firm evidence to decide on the risk or safety. Therefore, the most important rule if you are pregnant or trying to conceive is to consult your physician before taking any prescribed or over the counter medication. Drugs such as marijuana, nicotine and alcohol should be avoided. Your physician will balance the potential benefits of drugs treatment against any possible risk to decide whether or not a drug should be taken. This is particularly important if you need to take regular medication for a chronic condition such as epilepsy, high blood pressure or diabetes.
DRUGS AND THE STAGE OF PREGNANCY
Pregnancy is divided into three month stages called trimester. Depending on the trimester in which they are taken, drugs can have different effects on the mother of the fetus or both. Some drugs may be considered safe during one semester, but not another. Physician, therefore, often need to change regular medications given during the course of pregnancy.
THE TRIMESTER OF PREGNANCY
First trimester during the first three months of pregnancy- the most critical period- drugs may effect the development of fetal organs, leading to congenital malformations. Very severe defects may result in miscarriage.
Second trimester From the fourth through the sixth month some drugs may retard the growth of the fetus.This may also result in a low birth weight.
Third trimester During the last three months or pregnancy, major risk include breathing difficulties in the new born baby. Some drugs may also affect labor, causing it to be premature, delayed or prolonged.
HOW DRUGS CROSS THE PLACENTA
The placenta acts as a filter between the mother’s bloodstream and that of the baby. It allow small molecules from the nutrient to pass into the baby’s blood, while preventing larger particles such as blood cells from doing so. Drug molecules are comparatively small and pass easily through the placenta barrier.
How drugs pass into the breast milk the milk producing glands in the breast surrounded by a network of fine blood vessels. Small molecules of substances such as drugs pass from the blood stream into the milk. Drugs that dissolve easily in fat may pass across in greater concentrations than other drugs. Just as drugs may cross from the mother bloodstream into the baby’s through placenta, They may also pass to the baby from mother’s milk. This means that a breast fed baby will receive small doses of whatever drugs the mother taking. In many cases this is not a problem, because the amount of drugs that passes into the milk is too small to have any significant effect on the baby. However, some drugs can antibiotic may sensitize the infant and consequently prevent their use later in life. Sedative drugs make’s the baby drowsy and cause feeding problems. Moreover, some drugs may reduce the amount of milk produced by the mother. Physician usually advise breast-feeding woman to take only essential drugs. When a mother needs to take regular medications while breast-feeding, her baby may also need to be closely monitored for possible adverse effects.
Older people are particularly at risk when taking drugs. This is partly due to the physical changes associated with aging, and partly to the need for some elderly people to take several different drugs at the same time. They may also be at risk because they may be unable to manage their treatment properly, or may lack the information to do so.
Physical changes Elderly people have a greater risk of accumulating drugs in their bodies because the liver is less efficient at breaking drugs down and the kidneys are less efficient at excreting them. Because of this, In some cases, the normal adult dose will produce side effects, and half of the dose may be sufficient to produce therapeutic effect with out the side effects. Older people too, take more drugs than younger people- many take two or more drugs at the same time. Apart from increasing the number of drugs at a time can cause adverse drug interactions.
As people grow older some part of the body, such as the brain and nervous system, become more sensitive to drugs, Thus increasing the likelihood of adverse reactions from drugs acting on those sites. A similar problem may occur due to changes in the body’s ratio of body fat. Although allergic reactions are rarely a functions of age, changes in the immune system may account for some unexpected reactions. Accordingly, physician prescribe more conservatively for older people, especially those with disorder likely to correct themselves in time.
INCORRECT USE OF DRUGS
Elderly people often suffer harmful effects from their drug treatment because they fail to take their medications regularly or correctly. This may happen because they have been misinformed about how to take or receive vague instructions. Problem arise sometimes because many elderly people cannot remember whether they have taken the drug and take a double dosage. Problem may also occur because of the person confused; This is not necessarily due to senility, but can arise as a result of drug treatment, especially if an elderly person is taking a number of different drugs or sedative drug. All prescriptions of the elderly should be especially clearly and fully labeled. leaflets about the drugs and its use are also helpful for the individual or the person taking care of him or her. Where appropriate, special container with memory aids should be used for dispensing the medication in single doses.
KIDNEY AND LIVER DISEASE
Long term illness affect the way in which people respond to a drugs treatment. This is especially true of kidney and liver problems. The liver alters the chemical structure of many of the drugs that enter the body into simpler substances, while the kidneys excrete drugs in the urine. If the effectiveness of the liver of kidneys is curtailed or interfered with by illness, the effect of the drugs on the individual can be marked. In most cases, people with kidneys or liver disease will be prescribed a smaller number of drugs may in rare cases damage the liver or kidneys. A physician may therefore be reluctant to prescribe such as a drug to someone with already reduced liver or kidney function to avoid the risk of further damage.
Drug and kidney disease people with poor kidney function are at greater risk from drugs side effects, There are two reason for this. First drugs build up in the system because smaller amount are excreted in urine. Second, kidney disease can cause protein loss through the urine; that lower the level of protein, and if there are fewer proteins, a greater proportion of drugs becomes free active in the body.
Drugs and liver disease Severe liver disease such as cirrhosis of the liver and hepatitis affect the way the body breaks down the drug. This can lead to dangerous accumulation of certain drugs in the body. People suffering from this kind disease or anything similar should consult their physician before taking any medication including over the counter drugs or alcohol. Many drugs must be avoided completely since they can cause coma in someone with a damage or poorly functioning liver