Drug Dependence

Drug Dependence, psychological and sometimes physical state characterized by a compulsion to use a drug to experience psychological or physical effects. Drug dependence takes several forms: tolerance, habituation, and addiction.

Tolerance, a form of physical dependence, occurs when the body becomes accustomed to a drug and requires ever-increasing amounts of it to achieve the same pharmacological effects. This condition is worsened when certain drugs are used at high doses for long periods (weeks or months), and may lead to more frequent use of the drug. However, when use of the drug is stopped, drug withdrawal may result, which is characterized by nausea, headaches, restlessness, sweating, and difficulty sleeping. The severity of drug withdrawal symptoms varies depending on the drug involved.

Habituation, a form of psychological dependence, is characterized by the continued desire for a drug, even after physical dependence is gone. A drug often produces an elated emotional state, and a person abusing drugs soon believes the drug is needed to function at work or home.

Addiction is a severe craving for the substance and interferes with a person’s ability to function normally. It may also involve physical dependence.

Scientists often measure a drug’s potential for abuse by conducting studies with laboratory animals. Drugs that an animal administers to itself repeatedly are said to have powerful reinforcing properties and a high potential for abuse. These drugs include some commonly abused substances like opium, alcohol, cocaine, and see barbiturates. Other drugs, such as marijuana and the hallucinogens (see Psychoactive Drugs), appear to produce habituation in humans even though they are not powerful reinforcers for laboratory animals.

The drugs that are commonly abused, except alcohol and tobacco, can be grouped into six classes: the opioids, sedative-hypnotics, see stimulants, hallucinogens, cannabis, and inhalants.

Liver Disease

Diseases of the liver range from mild infection to life-threatening liver failure. For many of these ailments, the first sign of a problem is a condition called jaundice, characterized by a yellowish coloring of the skin and the whites of the eye. It develops when liver cells lose their ability to process bilirubin, the yellowish-brown pigment found in bile.

The liver can be harmed whenever injury or disease affects the rest of the body. For example, cancer may spread from the stomach or intestines to the liver, and diabetes, if not properly treated, may result in damage to the liver. Some diseases caused by parasites, including amebiasis and schistosomiasis, can damage the liver. Drug use, including long-term use of some prescription medications as well as illegal drugs, can also cause liver damage. Poisons can easily damage liver cells and even cause complete liver failure, especially the poisons found in certain mushrooms.

One of the most common liver diseases is hepatitis, an inflammation of the liver. Hepatitis may be caused by exposure to certain chemicals, by autoimmune diseases, or by bacterial infections. But hepatitis is most often caused by one of several viruses. The hepatitis A virus (HAV) can produce flulike symptoms and jaundice, but many people who contract it have no symptoms. The disease tends to resolve on its own. Because HAV lives in feces in the intestinal tract, hepatitis A is prevalent in areas where drinking water is contaminated with raw sewage. Good hygiene practices and a hepatitis A vaccination are effective measures of prevention.

Hepatitis B is a more serious ailment. Unlike HAV, hepatitis B virus (HBV) may remain active in the body for many years after the time of infection, sometimes permanently damaging the liver. HBV is found in blood and other body fluids—tears, saliva, and semen—and is spread through unprotected sexual intercourse and the sharing of infected needles or other sharp objects that puncture the skin.

In developed countries, alcohol-induced liver diseases far outnumber hepatitis and all other liver disorders. Heavy alcohol use causes fat deposits to build up in the liver, possibly leading to chronic hepatitis, which causes scarring and destruction of liver cells. Over many years, scarring in the liver can progress to cirrhosis, a disease characterized by diminished blood flow through this important organ. When this occurs, toxins are not adequately removed from the blood, blood pressure increases in the hepatic portal vein, and substances produced by the liver, such as blood proteins, are not adequately regulated. Cirrhosis cannot be reversed, but liver function can significantly improve in people who stop consuming alcohol during the early stages of this condition. Beyond abstinence from alcohol, treatments for cirrhosis may include drug therapy or surgery to redirect blood flow.

Obstetrics

Obstetrics, branch of medicine that specializes in caring for women during pregnancy, labor, and immediately following childbirth. The term derives from the Latin obstare, meaning to stand by, or opstare, meaning to render aid, and obstetrix, meaning the woman who stands by. Until the early 18th century, childbirth assistants were usually midwives, women who provide care to other women during pregnancy and childbirth. During the 19th century, obstetrics evolved as a medical specialty. Physicians who specialize in obstetrics are called obstetricians.

Obstetricians are commonly also certified in gynecology, to provide care for a wide range of problems involving the reproductive system. Obstetricians with special training in high-risk pregnancy are referred to as maternal-fetal medicine specialists or perinatologists. Many physicians in family practice include obstetrics and some gynecologic surgery in their practices. In addition, midwifery is practiced in many parts of the United States, as well as throughout the world. Women may choose midwives in areas where physicians are unavailable or unaffordable, or because they believe in a less medicalized approach to childbirth.

Obstetrical care ideally begins with the counseling of a woman who is either planning a pregnancy or at risk for an unplanned pregnancy. Preconception counseling may include assessment of lifestyle, including issues such as diet, exercise, consumption of alcohol or tobacco, and ways of dealing with stress; recommendation of vitamins; administration of necessary vaccinations; and general advice about maintaining healthy habits. Throughout a pregnancy a woman may schedule eight to ten or more visits to her obstetrician, during which tests are performed, such as blood typing—in preparation for possible blood transfusion, and to determine if there are incompatibilities between the mother’s and baby’s blood—and screening for infectious diseases. Specialized tests to monitor the health of the fetus may be recommended, including ultrasound to visualize the fetus, and genetic testing to learn the risk for genetic diseases such as Down syndrome.

An obstetrician attends the woman during labor and delivery and is trained to handle any complications that would endanger the mother and fetus. Complications may include premature rupture of the membranes, in which the water bag ruptures but labor does not begin spontaneously; failure to progress, in which labor has begun but the woman’s cervix—the small organ that connects the uterus to the vagina—fails to widen or dilate properly; or breech presentation, in which the fetus is oriented feet first down the birth canal instead of head first. Obstetricians perform cesarean sections, in which the fetus is removed through an abdominal incision, and they also surgically repair injuries to the birth canal that may occur during delivery. Immediate care of the mother for several weeks after delivery is generally considered part of obstetrical practice. Once a baby is delivered, its care may be assumed by a pediatrician (see Pediatrics), a specialist in the care of children.

Obstetricians complete four years of medical school, followed by four or more years of primary care training and training in obstetrics and gynecology. After completing an approved training course and a period of practice, obstetricians may take an examination for board certification, a nationally recognized acknowledgment of expertise in a specialty. In addition, physicians planning to specialize in gynecologic cancer, infertility, or reconstructive surgery may complete two to three years of additional training to receive board certification in their particular subspecialty.

Beta Blocker

Beta Blocker, any of a group of drugs used to treat various disorders associated with the circulatory system. These disorders include high blood pressure (hypertension), angina pectoris (chest pains caused by reduced oxygen flow to the heart muscle), irregular heartbeat, and migraine headache. Beta blockers are also effective in treating glaucoma, an eye disorder characterized by excessive pressure within the eye.

Properly known as beta-adrenergic blocking drugs, these drugs interfere with actions of the sympathetic nervous system, which controls involuntary muscle movement. They slow the heart rate, relax pressure in blood vessel walls, and decrease the force of heart contractions. In the eye they reduce the formation of excess fluid. Specific beta blockers include timolol, atenolol, and metoprolol.

Beta blockers are prescription drugs available as tablets taken in one or more doses ranging from 2.5 to 1200 mg per day, depending on the drug. Eye drops are administered as a single drop once or twice per day. Effectiveness is usually apparent after one to two weeks of treatment. Patients taking beta blockers should not stop taking them abruptly, as their condition may worsen. These drugs are not recommended for use during pregnancy.

Possible side effects associated with beta blockers include depression, diarrhea, light-headedness, itching, rash, nausea, fatigue, shortness of breath, and a slow heartbeat. Beta blockers may interact adversely with digoxin, diltiazem, verapamil, chlochlorpromazine, and haloperidol.

Gout

Gout, complex disease of uncertain origin caused by the faulty metabolism of uric acid produced in the body by breakdown of protein, and resulting in elevated levels of uric acid in the blood. A diet rich in malt liquors, wines, and certain types of protein may precipitate individual attacks but does not cause the disease. Its incidence is not usually affected by climate or season; about 95 percent of sufferers are men. The disease is rare in people under the age of 30; from 10 to 20 percent of cases have a familial history.

Acute attacks are characterized by severe pain in the joints, often in the big toe, but sometimes in the ankle, knee, hip, shoulder, wrist, or elbow. The attack usually begins abruptly; the joint becomes swollen, red, inflamed, and extremely tender. Untreated attacks last from a few days to a week or more.

Repeated attacks may result in the development of a condition known as chronic tophaceous gout. In this condition crystals of uric acid lodge as white, chalky material in soft body tissues and in and about the joints, where they may cause bursitis and destruction of bone. Large and deforming deposits may, after many years, settle in the outer margins of the ears, a characteristic feature of the disease. Chronic gout may also cause kidney damage by the formation of uric acid stones, a condition called urate, or gouty, nephropathy.

The treatment of both types of gout calls for complete rest of the limb and a simple diet, low in poultry, legumes, liver and other organ meats and high water intake to reduce the uric acid content of the body. Sodium salicylate and corticosteroids may be prescribed, or a corticosteriod may be injected into the affected joint. The acute phase is managed with anti-inflammatory drugs, such as colchicine or indomethacin. Chronic gout is usually treated by agents that promote excretion of uric acid, such as probenecid, and agents that inhibit production of uric acid, such as allopurinol.