Some medications are effective directly over the area they are applied to. Some however are transported to distant regions via blood flow and that is where they are most effective. Medication is either taken orally or through injection. When medicine passes into the blood stream from the place of administration, it is considered to be absorbed. A good example is the transportation of medicine into the blood stream of capillary vessels between the muscle cells when injected into muscle tissue. A drug taken orally however is absorbed through the blood vessels in the gastro-intestinal system.

For orally-taken medication to be absorbed, it should be able to dissolve in gastro-intestinal fluids. First, it is broken into smaller units due to the corroding effects of stomach acid and various enzymes are secreted, then chemicals in the drug composition pass into the gastro-intestinal fluid in a molecular form. This event resembles the dissolving of a sugar cube inside a glass of hot tea. First, the sugar cube gets broken into pieces and then dissolves. A mix with a tea spoon makes this event happen a little faster. In a similar fashion gastro-intestinal movements help with the absorption of medicine. Liquid drugs like syrups dissolve in the gastro-intestinal fluid faster since they are already in smaller units; therefore they get absorbed faster.

Drugs mostly get absorbed through the small intestine. The most important task of this organ is to enable the absorption of nutrients. It is approximately 10 meters long and 4 centimeters wide. The inner lining of the small intestine has finger-like projections called villus and even smaller projections that are located on these villi are called microvillus. One of the reasons, maybe the most important reason, why the our intestines are created in this way is that as a result, the inner surface area of intestines increases multifold. Such that the inner surface area of a human beings small intestine can increase up to 200 m2 and this greatly facilitates the absorption. These projections are made of intestinal cells.

The molecules carrying the medication reach the capillary vessels by passing through these cells and then join the blood stream by crossing through capillary vessel cells. Furthermore, intestinal cell membranes host a special protein that filters unwanted substances for the cell and returns them back to intestinal lumen. Thus these unwanted substances are excreted out of the body along with other unabsorbed matter. In the same way, some drugs are held by this protein and released back into the lumen thus decreasing absorption rate for drugs experiencing this reaction.

Liver: The organ responsible for eliminating the harmful effects of medication

As soon as medication joins the bloodstream after absorption, it is first transported to the liver. This is because pulmonary veins that collect blood from the intestines are connected primarily to the liver. One of the many functions of the liver is the elimination of harmful substances entering the body. For this reason, absorbed substances are directly sent to the liver. The liver is employed with the task of chemical conversion with these substances that are transported to it. One of the wisdoms behind liver metabolism is to reduce the effects of these harmful substances via these events and to convert them into an excretal material. In the same way, drugs are metabolized in the liver, lose their efficacy and prepare for excretion.

Many drugs interfere with each other’s metabolism. If one drug’s metabolism is inhibited, blood concentration of such chemicals increase and adverse effects of drugs become more frequent. Irresponsible drug use must be avoided for this reason. Drug interactions may lead to major damage in addition to the drug’s individual adverse effects. Moreover different nutrients also affect drug metabolism. For instance, grapefruit inhibits metabolism of certain medicines, as a result blood concentration of these medicines increase and adverse effects can be observed. On the other hand, some nutrients like broccoli, cabbage, and charcoal roasted meat speed up the metabolism of certain medicines. In this case, the blood concentration of the affected drug drops and may lead to reduced benefits from intended use. Because of this reason, patients on long-term medicine treatment should not consume these types of food.

The rest of the drug molecules that escape these metabolisms is directed towards blood vessels feeding other organs. Some drug metabolisms in the liver present individual differences as metabolic levels change from person to person. Thus, a drug with the same dosage develops desired blood concentrations for some people, fails to meet this level for others or can even cause high blood concentrations enough to generate adverse effects in other individuals. That is why a medicine that has benefited a patient should never be used by somebody else without consulting a doctor.

The function of bile

Bile secretion originating from the liver and gall bladder has critical importance in the digestion and absorption of fats. Bile breaks apart fats into small pieces so that digestive enzymes can affect them. As a result of this, absorption is provided for fats and vitamins like A, D, E, K that are soluble in fats. In a similar fashion bile improves solubility and absorption of some drugs that does not dissolve in gastro-intestinal fluid. Another task of bile secretion is the removal of certain substances from the body. Waste materials in the bile that is dumped into duodenum are excreted through the digestive track. Some drugs are excreted in this way.

Drug intake before or after meals

It is a well known practice that medications are advised either to be taken after or before meals. When medications are taken after a meal, they cause less of the possible unwanted disturbances such as stomach sickness, aches or indigestion.

On the other hand, nutrients may reduce intake of certain drugs, therefore they need to be taken before meals. However medications taken right before a meal does not apply in this case since the food will still mix with the medication in the stomach. When taking these medicines, it should at least be an hour before meals. Generally consumption of a medicine before or after a meal does not really change its absorption level. But medications taken before meals pass the stomach into the intestines without delay and therefore get absorbed faster. This practice is important in cases where an immediate effect is desired such as pain relief. Plentiful water intake also helps with faster and improved absorption of drugs.

Some medications are packed into capsules made of gelatin-like substances. Medicines with undesirable taste and smell can be offered in this form for consumption. Moreover, if a drug is harmful to the stomach or gets degraded in stomach acid, then this drug can be prepared in capsules that are durable to stomach acid but soluble in the intestines. That is why consumption of medication without its intended capsule should be avoided. In a similar fashion, some medicinal tablets are designed to deliver its molecular contents particularly to the intestines. These types of medication must be taken as a whole unit. Otherwise it can be ineffective or may lead to harmful reactions.

Delivery of drugs to targeted regions

The molecules carrying medication that join the blood via absorption get dispersed by blood circulation throughout the body. These molecules reach various parts of the system via blood vessels, and then diffuse into organs via capillary vessels. However, their entry to the brain is difficult because this vital organ of the body has a special protection to guard itself from possible harmful effects of various substances that enter the body from the outside. Capillary vessels in the brain are different from other capillary structures in the rest of the body as they are created without an intercellular space in between vessel cells. Furthermore, these cells are bound to each other with their tight connective regions.

These capillaries are surrounded by a thicker membrane compared to other capillary vessels. This membrane is also host to various cells that wrap around the vessel. Therefore, because of these factors and other similar ones, some medications can enter the brain in very limited amounts. Drug molecules can display their targeted effects when they bind to target proteins, called receptors, in the organs. These proteins, which are very unique to each drug, exist on the cell membrane or in the cell. In addition, drug molecules also bind to other receptors that are not specific for them, and this causes adverse effects as a result.

Excretion of drugs from the body

Drugs are excreted from the body via the liver and kidneys. One function of these organs is to filter the blood from foreign substances. It was previously mentioned that absorbed substances from intestines are transported to the liver first where some amount gets metabolized and the remaining amount rejoins blood circulation that feeds other organs. Drug molecules that pass through the liver return back to it repeatedly many times because of continual blood circulation. In each of these arrivals, some amount is again metabolized. Molecules of metabolized drugs are excreted out of the body via the kidneys and through the bile at a limited level.

Only some portion of drug molecules get excreted via the kidneys without being metabolized. This ratio is higher with some medications. These types of medications are considered to be removed only by the kidneys, whereas some other drug types cannot be excreted without getting metabolized through the liver. As previously mentioned, the purpose of drug metabolism is to convert drugs into easily removable forms. If these types of drugs are not metabolized, they are rejoined to the blood circulation after filtration by the kidneys without joining the urine. It is impossible for the liver to sense these happening within the kidneys if it was not that the liver and every cell in it were employed by one authority who created them in the first place. Drug molecules concentrate in the liver and kidneys since these organs are employed with drug removal. As a result harmful effects of drugs are often experienced in these organs. Therefore unnecessary drug use should be avoided, otherwise the health of these organs deteriorate and eventually fail to carry out their basic functions.

As noted above, events that are taking place within many of our organs, stomach and elsewhere like kidneys impact on the journey of drugs in our body, therefore changing its effect. The harmonious creation of our organs that are home to many miraculous events is the major component of the entire process in which causations have their due role only as much as they are allowed by their Creator. As a test for humankind, both illness and the cure is provided by God, the All-Healer. Therefore it is the duty of a patient to see a doctor, take the medication properly and never forget that cure is only provided by the Almighty, without obsessing over causational chains.

References

• Guyton, Arthur C., John E. Hall. 1991. Textbook of Medical Physiology, Saunders.
• Patton, Kevin T., Gary A. Thibodeau. 1993. Anatomy & Physiology, Mosby.
• Rang, Humphrey P., Maureen B. Dale, James M. Ritter. 1999. Pharmacology, Churchill Livingstone.
• Brunton, Laurence, John Lazo, Keith Parker. 2006. The Pharmacological Basis of Therapeutics. McGraw-Hill Professional

All the organs functioning in your body have a direct or indirect relationship with me. I can be compared to a kind of “chemical brain.” All metabolic activities are among my duties, including the control of excretions, digestion, and the composition of blood. You would be stupefied if I listed every single function I carry out, but let me tell you this much: biochemists have discovered that I am directly included in more than 80 different activities and related to more than 5,000 chemical reactions taking place in your body. Surprised? But this is only what they’ve learned so far; you do not know me in detail yet. My plain appearance is in contrast with my numerous functions. My size is about one-tenth of the body of a six-month-old fetus; now that you have become a young man, I weigh about one fiftieth of your body weight. Since I am the largest excretory organ in your body, I am firmly strapped with mesentery so you can run, jump, and make other movements without trouble.

Most people see me merely as a bile-producing organ, which happens to be among the simplest of my duties. Let me explain it another way: the heat I produce while working is equal to one-third of the heat your body produces while resting. I have a special circulatory system. Since I am located at a “junction,” the blood coming from the intestines which bear nutrient molecules come to my vein first together with the blood from the spleen, before joining the rest of the bloodstream. It can be compared to an obligatory customs check. The amount of blood I supervise within 24 hours is about 2,000 liters. With every heartbeat, almost 28 percent of the blood being pumped passes through me.

I adjust the level of blood sugar in a very sensitive balance. If you eat desserts or pastries I convert excess sugar into glycogen (animal starch) and store it. If your blood sugar decreases from hunger, I break down glycogen into sugar (glucose) and come to your help so that you do not come to a halt, like a car out of fuel.

I use various protein molecules to synthesize numerous enzymes. I also play a role in blood coagulation, red blood cell production, and storing the iron you need. You know, nothing is wasted in the divine system of nature. So how can I waste anything? When the aged red blood cells die, I help the spleen to break them down and store the iron they contain. My job in fat metabolism is no less important. Thanks to the bile I produce, the fatty food you eat is broken down to smaller molecules to be absorbed in a way similar to detergents remove oily remnants from dishes. Naturally, the fat-soluble vitamins (A, D, E, K) are also absorbed along the process. I store the excess of both these vitamins and fats. Fats are an important fuel particularly for your heart muscles. I excrete an average of 600–700 grams of bile a day. Two minutes after oily foods pass to duodenum the walls of my gallbladder are operated. Through contractions of 2–6 times a minute and a pressure of 25–30 mmHg, the bile is passed to duodenum in a time span of 15 to 90 minutes. What gives bile its yellowish-green color is the substance named bilirubin, which appears with the breaking down of the old red blood cells and disposed of through the bowels.

The Kuppffer cells—as you name them—have the duty of checking out newly produced blood cells one by one in addition to producing antibodies against germs. If any ill-formed blood cells come up, I must detect and destroy them. Otherwise they corrupt your blood. Thanks to the Kuppffer cells, the ill-formed blood cells are destroyed as soon as they are detected.

The average longevity of my cells varies between 150-180 days (220 days maximum). New cells are produced immediately to replace the dying ones and the system works smoothly. In each of these cells there are 1,000-3,000 mitochondria and millions of ribosome. An average of 180 new ribosome are produced every second. Although none of my cells have consciousness or intelligence, thousands of them come together to form little lobes resembling hexagons. The number of these lobes varies between 50,000 to 100,000.

Dear Peter, you intake various toxic substances together with the foods you eat. You don’t even realize that food has been corrupted by bacteria and fungi until its taste changes. Frankly, you should not have lived very long with so much toxic intake; Providence has given me an important duty to protect you from such harm. I capture these toxic compounds released into your bloodstream and neutralize them. The same goes for different medicines you take; I try to neutralize their toxic effects as well. But I have my own limits of tolerance; if I am faced with more toxic substances than I can handle, then I give signals of danger. You wonder how. Well, I shout “help” through red spots in your hands and itchy spots on your skin. You should be more careful about what goes down your throat.

Given that I fulfill various important functions, the littlest failure in me reveals itself as a health problem immediately. Hepatitis is among the common diseases heralding my failure. Excessive increase of bilirubin in your blood causes the white of your eye and your skin to turn yellow. I fear viruses most. Particularly hepatitis B and C viruses destroy my tissue. And alcohol, as you know, is my sworn enemy. I have to exert myself to neutralize even a tiny amount of alcohol. And if the hepatitis virus is added, I become knocked down and contract cirrhosis. It does not happen suddenly, though. Along the process which you know as liver failure I give various signals: skin eruption, digestion problems, sleepiness, and headache after meals, and so on. Since these symptoms are not serious problems, most people ignore these signals I give. Due to my various functions, the lab tests about me are more than a hundred.

Talking about my enemies may have upset you a bit, but it’s not all doom and gloom. After all, I am the organ with the highest capacity to renew itself. Sounds good, right? Otherwise I would have been finished off long ago, so this ability is a real blessing. Let me give you an example: although 90 percent of my cells are destroyed during hepatitis, I can help you survive with the remaining 10 percent if you rest well and control what you eat. If you ignore the disease, it might lead you and me to the grave. Do not ever believe those who take this lightly and say: “This doctor says that a small amount of alcohol is good for health.” Tell it to the marines. Those who say that should visit hospitals first. I’m sorry, Peter, but it really gets on my nerves. If they could only appreciate a work of art like me. Anyway, that’s all for now, please take good care of me.