Cyclosporine

Cyclosporine, name of a drug approved for clinical use in the United States in 1983. The drug is important because of its ability to suppress the action of the body's immune system in rejecting foreign tissues following organ transplant operations (see Medical Transplantation). Specifically, it blocks the activity of certain cells in the immune system called T cells, which, in combination with cells in the bloodstream, would otherwise tend to attack the tissues of the transplanted organs. Operations of this nature have proved successful a great percentage of the time when using cyclosporine. There is some risk of potentially severe kidney damage, however, so care must be taken in administering the drug. Cyclosporine occurs naturally in a certain Norwegian fungus, Tolypocladium inflatum.

Conjunctivitis

Conjunctivitis, inflammation of the conjunctiva, a mucous membrane that lines the inner surface of the eyelids and joins with the cornea of the eyeball. Conjunctivitis may be caused by infection, allergy, or injury and is marked by redness and swelling, accompanied by a feeling of roughness as the membrane passes over the exposed surface of the eyeball. The eye may be sensitive to light; in more severe cases a mucoid sticky fluid, or even pus, may be discharged, depending on the cause of the infection.

The acute form of conjunctivitis is commonly called pinkeye. It can be caused by either bacterial or viral infection and is often epidemic. In newborn babies it may result from several kinds of cocci, especially the gonococcus (gonorrheal conjunctivitis), or from a strain of the parasitic bacterium Chlamydia trachomatis (inclusive conjunctivitis). A strain of fly-borne Chlamydia trachomatis causes trachoma, a severe form of conjunctivitis found mostly in Africa and Asia. As in gonorrheal and inclusive conjunctivitis, trachoma often results in blindness because of the involvement of the cornea. Conjunctivitis caused by exposure of the eye to a welding arc or other source of ultraviolet rays is called flash kerato-conjunctivitis.

Most cases of bacterial conjunctivitis are treated successfully with antibiotics and sulfonamides. Viral conjunctivitis usually lasts about two weeks; treatment may be necessary in cases that involve complications. Silver nitrate or antimicrobial ointments are applied to the eyes of newborn babies to prevent ophthalmia neonatorum.

See also Eye.

Cirrhosis

Cirrhosis, irreversible liver damage characterized by scarring, or fibrosis, and widespread formation of nodules in the liver. If left untreated, the liver becomes unable to carry out its functions, resulting in complications that affect many different systems of the body.

Cirrhosis can result from virtually any chronic liver disease. When hepatocytes, the major liver cells, are damaged or die, they are replaced by scar tissue. Liver tissue may also regenerate in an abnormal pattern, forming tiny balls known as nodules.

A number of inherited metabolic diseases can cause cirrhosis, such as hemochromatosis (abnormal accumulation of iron), Wilson’s disease (inability to metabolize copper), and some forms of alpha-1-antitrypsin deficiency (inability to produce the alpha-1-antitrypsin protein). Cirrhosis can also result from certain autoimmune diseases in which the body’s immune system attacks and destroys liver tissue. In some parts of the world, parasitic infections are a common cause.

Especially in its early stages, cirrhosis is often symptomless. Some patients suffer from fatigue, particularly when they exercise. Some experience itching due to a buildup of bile, a yellowish brown liquid that aids in the digestion of fats, in the blood and skin. Later in the disease, the formation of nodules distorts the liver’s structure. This distortion slows the flow of blood through the liver, causing an increase of blood pressure in the portal vein, the main blood vessel that empties into the liver. This increase in blood pressure, known as portal hypertension, can lead to the formation of enlarged, twisted varicose veins in the stomach and esophagus. If these veins rupture, life-threatening internal bleeding can develop. Portal hypertension can also cause the spleen to become enlarged and trap platelets (tiny blood cells that aid in clotting), impairing the body’s ability to repair wounds.

As the liver's capacity to function is compromised, a variety of complications develop throughout the body. Jaundice results from the liver’s inability to process bilirubin, a pigment that forms as a result of the breakdown of old red blood cells. The buildup of this pigment causes the yellow discoloration of the skin and eyes characteristic of jaundice. Decreased production of a blood protein known as albumin, along with hormonal and kidney abnormalities, leads to retention of fluid, especially in the abdomen. Decreased production of clotting factors by the liver makes cirrhosis patients bruise and bleed easily. Inefficiency in breaking down toxins in the blood can cause neurological symptoms, including confusion, sleeplessness, and even coma. Cachexia, a general loss of weight and strength due to poor absorption of nutrients, can also develop.

The surest way to diagnose cirrhosis, especially in the earlier stages when symptoms are minimal, is by liver biopsy, in which a doctor uses a hollow needle to collect a small sample of liver tissue. In more advanced cases, symptoms such as jaundice, fluid in the abdomen, and generalized muscle wasting suggest a diagnosis of cirrhosis. Blood tests that show low albumin levels, elevated bilirubin levels, clotting problems, or other abnormalities can also point toward cirrhosis. Radiological tests such as ultrasound can sometimes detect advanced cases of cirrhosis.

Although cirrhosis is irreversible, treating the underlying cause of the liver damage can dramatically limit further destruction of liver tissue and help prevent the development of complications. For alcoholic cirrhosis, abstinence from alcohol is the key element of treatment. Damage from the hepatitis B or C virus can be limited with antiviral drugs such as alpha interferon. In patients with hemochromatosis, removal of blood to decrease iron levels in the body helps prevent liver damage. In advanced cases of cirrhosis, the goal of treatment is managing complications such as fluid retention, internal bleeding, and neurological symptoms. When drugs and other medical interventions can no longer control such complications, liver transplantation can be lifesaving.

Ciprofloxacin

Ciprofloxacin, drug used to treat bacterial infections in the lower respiratory tract, urinary tract, bones, joints, and skin. It is also used to treat serious ear infections, cholera, tuberculosis, infectious diarrhea, and infections associated with acquired immunodeficiency syndrome (AIDS). Ciprofloxacin is prescribed after exposure to the bacteria that cause anthrax to reduce the incidence or progression of the disease. For maximum effectiveness against inhalation anthrax, the most dangerous form of the disease, the drug should be administered as soon as possible after exposure, even before symptoms appear. Ciprofloxacin works by blocking the action of gyrase, an enzyme needed by the invading bacteria for cell reproduction, thereby slowing or completely stopping bacterial growth.

The drug is available by prescription in tablets, which are taken orally with or without food, and in a liquid, which is used in the form of eyedrops. Depending on the severity of infection, dosages for tablets range from 250 to 750 mg taken every 12 hours. Eyedrops are typically prescribed as one or two drops every 2 to 4 hours for the treatment of bacterial eye infections. Patients taking ciprofloxacin should drink plenty of fluids but avoid excessive caffeine. Pregnant women, breast-feeding women, and children under the age of 18 should not take this drug.

Possible side effects include abdominal pain, nausea, vomiting, headache, skin rash, sensitivity to light, or restlessness. Serious side effects should be reported to a doctor, as allergic reactions to this drug, while rare, can be fatal. Allergic symptoms may include facial swelling, shortness of breath, tingling or itching, hives, or unconsciousness.

Patients with severe liver disease, impaired kidney function, or with epilepsy or other disorders or injuries affecting the central nervous system should use this drug with caution. Those who experience dizziness or lightheadedness with this medication should not drive, operate dangerous machinery, or engage in other risk-related activities. Because of the possible risk of tendon rupture, strenuous physical activity should be avoided or approved by a doctor.

Ciprofloxacin should not be combined with the drug theophylline, as serious or fatal reactions can result. It may interact adversely with phenytoin and warfarin. Ciprofloxacin may be less effective when used in combination with vitamin supplements containing zinc or iron or with antacids containing calcium, aluminum, or magnesium.

Brand Names: Cipro, Ciloxan

Cimetidine

Cimetidine, drug used in the treatment of stomach and intestinal ulcers. It is used to treat reflux disease, a condition in which stomach acids back up into the esophagus causing heartburn, and to prevent upper abdominal bleeding. Cimetidine is also used to treat chronic hives, acne, herpes infections (including shingles), excessive hair growth in women, and an overactive parathyroid gland.

Cimetidine blocks the action of histamine, a chemical in the body that stimulates acid secretions in the stomach. When histamine action is blocked, secretion of stomach acid decreases, allowing ulcers and other gastrointestinal ailments to heal.

This drug is available by prescription in tablet and liquid form, both taken orally, and in a liquid form that is injected. Depending on the condition being treated, typical dosages range from 800 to 1200 mg per day. Cimetidine may be taken in a single dose at bedtime or divided into two or four smaller doses, usually taken immediately after a meal. Relief of symptoms may take several days. Recurrence of ulcers after cimetidine treatment ends may be slightly higher than with other forms of treatment.

Patients taking this drug should avoid alcohol, cigarette smoking, and excessive caffeine. Patients should refrain from taking antacids within one to two hours of a cimetidine dose. This drug has not been proven safe for pregnant or nursing women or for children under the age of 16. It should be used with caution by patients with impaired liver or kidney function. It should not be stopped abruptly by patients taking it for peptic ulcer disease.

Breast development in men and headaches are the two most common side effects of this drug. Less common side effects are diarrhea, dizziness, anemia, hair loss, impotence, joint or muscle pain, skin rash or inflammation, rapid or slow heartbeat, and sleepiness. With prolonged use (one month or more), some patients experience anxiety, confusion, depression, or hallucinations. These reactions are more likely to occur in elderly or severely ill patients, but they are temporary and subside several days after drug treatment ends.

Cimetidine may interact adversely with a variety of drugs, including medications for diabetes, heart palpitations, and fungal infections as well as blood pressure drugs (both beta blockers and calcium blockers), benzodiazepine tranquilizers (such as diazepam), narcotic pain relievers, nicotine, and aspirin. Other drugs that may interact adversely include chlorpromazine, cyclosporine, digoxin, metoclopramide, metronidazole, paroxetine, pentoxifylline, phenytoin, quinine, sucralfate, theophylline, and warfarin.

Brand Name:Tagamet