1. Why Are Drugs Classified in the Categories They Are?

1. Why are drugs classified in the categories they are?
The term drug class generally refers to the area affected by a drug or its effect on the body (BIO-316V Module 2 Lecture, 2012). Many drugs can fit into more than one category, but they are usually classified by their therapeutic action. A drug’s therapeutic category refers to its purpose—the diseases or conditions it treats (Drug Classifications, 2013). Drugs can also be classified by the chemical type of the active ingredient.

2. Give a description of the actions of drugs in each category.
Central Nervous System:
Anticonvulsants: These drugs are used to control/prevent seizures in patients who have epilepsy, seizure disorders, traumatic brain injuries, or other cerebral disorders ((BIO-316V Module 2 Lecture, 2012).
Antidepressants: These drugs are used to treat neurotransmitter deficiencies (BIO-316V Module Lecture, 2012). It can take weeks for the drug to reach the appropriate blood level to have the desired effect.
Antianxiety/sedative medications: These drugs are used to treat anxiety disorders and sleep disorders. Barbiturates and benzodiazepines enhance the actions of the inhibitory neurotransmitter, gammaaminobutyruc acid. Agents in both classes are effective sedative-hypnotics , antianxiety agents, and anticonvulsants. (Olson, J., 2012).
Antipsychotics: These are medications that are used to treat psychotic episodes and serious mental disorders (BIO-316V Module Lecture, 2012). Schizophrenia is an example of a psychotic disorder that can be treated with an antipsychotic medication.
Antiemetics: These drugs treat nausea and vomiting and help control motion sickness (Olson, J., 2012).
Cardiovascular drugs:
Antihypertensives: These include diuretics which reduce blood pressure and edema by increasing urine production. (Olson, J., 2012).
Antiadrenergics: These medications increase blood pressure by stimulating the heart and/or constricting peripheral blood vessels. (Olson, J., 2012).
Vasodilators: These drugs help lower one’s blood pressure by dilating the blood vessels (Olson, J., 2012).
Vasoconstrictors: These help increase one’s blood pressure by constricting the blood vessels (Olson, J., 2012).
Anti-anginals: Nitrates dilate large myocardial arteries to increase blood supply to the heart. They also reduce cardiac preload by reducing venous tone which allows blood pooling in the periphery (Olson, J., 2012).
Anti-arrhythmias: These drugs influence cardiac conduction properties and may revert an abnormal rhythm to sinus rhythm (Olson, J., 2012).
Anticoagulants, antiplatelets, and thrombolytics:
Anticoagulants inhibit coagulation, antiplatelets prevent platelet aggregation and thrombolytics degrade clots that have already formed (Olson, J., 2012). All of these drugs need to be given carefully to avoid causing excessive bleeding. They should not be given to patients with ulcers, patients who are pregnant, or those who are suffering from a hemorrhagic stroke (BIO-316V Module Lecture, 2012).
Lipid Lowering Agents: These drugs help one reduce blood cholesterol when diet and exercise control fail (Olson, J., 2012).
Analgesic medications:
Analgesic medications are commonly known as pain relievers. Many are over-the-counter (OTC) drugs. Others are given to the patient by prescription for pain relief (BIO-316V Module Lecture, 2012). Narcotic medications stimulate central nervous system receptors known as opioid receptors and cause a decrease in the perception of pain. An overdose of narcotics can result in suppression of the respiratory system, leading to respiratory arrest (BIO-316V Module Lecture, 2012). Nonsteroidal anti-inflammatory drugs (NSAIDs) alleviate pain associated with inflammation (e.g., Aleve). They are used to relieve arthritis and other joint pain. Acetaminophen is a common pain reliever that does not cause bleeding. It is often given instead of NSAIDs (BIO-316V Module Lecture, 2012).
Antihistamines and Endocrine medications:
Antihistamine medications block the immune responses of itching, hives, and swelling caused by the release of histamines. These are available OTC (BIO-316V Module Lecture, 2012). Diabetes and hypothyroidism are two glandular conditions that are often observed by the health care professional. Antidiabetic medications are necessary for patients who cannot balance their blood sugar and tissue sugar. Insulin is the medication prescribed for insulin-dependent diabetes (type-1 diabetes) (BIO-316V Module Lecture, 2012). Hypothyroidism is controlled by common hormone preparations designed to enhance thyroid function. The most common of these is thyroxin (BIO-316V Module Lecture, 2012). Hyperthyroidism is typically controlled by a medication called methimazole and it inhibits transformation of inorganic iodine to organic iodine (Olson, J., 2012).
Bronchodilators help open constricted airways in patients who have respiratory constriction such as asthma and/or COPD (Olson, J., 2012).
Vasopressin is a drug which promotes reabsorption of water in the distal tubules and collecting ducts of the kidneys and vasoconstricts blood vessels. Vasopressin and DDAVP are synthetic analogs of arginine vasopressin used to treat diabetes insipidus. (Olson, J., 2012). Desmopressin is used to treat acute epistaxis and GI hemorrhage and also used to maintain hemostasis during surgery in patients who have hemophilia A and Von Willebrand’s disease (Olson, J., 2012).
Oxytocin induces contraction in the gravid uterus and promotes milk ejaculation from the post partum breast (Olson, J., 2012).
Oral contraceptives help prevent pregnancy (Olson, J., 2012).
Corticosteroids:
These include Hydrocortisone, Prednisone, Prednisolone, Triamcinolone, Dexamethasone, and Fludrocortisone. These medications are typically used for respiratory issues such as asthma, and a few of them care also used as an anti-inflammatory agent to help reduce swelling and allow the patient to breathe better. Prednisone is the drug of choice for maintenance therapy of severe asthma. Prednisone doesn’t just help reduce swelling in the lungs; however, it can be used for other inflammatory issues all over the body (Olson, J., 2012).
Anti infective agents:
Antibiotics are drugs used to fight infections caused by bacteria. As their name implies, antibiotics are "anti-life" agents as far as bacteria are concerned (BIO-316V Module Lecture, 2012). Antifungal drugs are used to combat all sorts of fungal infections, from athlete 's foot to histoplasmosis. They are being used more often now in the combating of AIDS-related fungal infections (BIO-316V Module Lecture, 2012). Antiviral agents fight viral disease at the cellular level. Viruses enter into cells and propagate within them. Antibiotics have no effect on a virus once it has entered a cell. Antiviral agents are designed to interfere with the replication of viruses (BIO-316V Module Lecture, 2012).
Chemotherapy Agents:
Chemotherapy is typically used to treat cancer. This is achieved by using a combination of drugs that are most toxic to the particular cancer cells of an individual patient. They are very potent and could be harmful to the caregiver (BIO-316V Module Lecture, 2012).

GI Agents:
Antidiarrheals: These drugs help control diarrhea amd most are sold OTC, although there are a few that can be prescribed and are more potent than the OTC drugs (Olson, J., 2012).
Laxatives: These drugs are the opposite of antidiarrheals, as they help a patient who is unable to have a bowel movement (Olson, J., 2012).
Antacids provide symptomatic relief of gastric acid irritation (Olson, J., 2012).
Anti ulcer drugs help treat or prevent ulcers by either neutralizing gastric acid or preventing the production of acid (Olson, J., 2012).
3. What is chemotherapy and which diseases are treated this way? Chemotherapy by definition is the combination of two or more drugs used to treat a disease (BIO-316V Module Lecture, 2012). Most anticancer agents act by inhibiting cell proliferation by either damaging DNA or preventing DNA repair (Olson, J., 2012). Chemotherapeutic regimens often consist of several agents that have different mechanisms of action and minimize overlapping toxic effects (Olson, J., 2012). Most anticancer drugs cause bone marrow suppression which is why bone marrow sparing drugs are often included in combination regimens (OIson, J., 2012). Chemotherapy is used to treat cancer.
4. Give examples of how contrast media are used to produce an image.
Contrast studies provide some information that standard x-rays cannot. During a contrast study, you get a dose of a contrast material that outlines, highlights, or fills in parts of the body so that they show up more clearly on an x-ray. The contrast material may be given by mouth, as an enema, as an injection,or through a catheter put into various tissues of the body. For most of these tests, the images can be captured either on x-ray film or by a computer (American Cancer Society, 2013). An image is produced on a radiograph when the content of iodine in the blood is sufficient to prevent the penetration of the photons emitted by the X-ray tube (BIO 316V Module 2 Lecture, 2012).
5. Compare ionic and non-ionic contrast media.
Ionic contrast media carry the iodine to the organ that is to be visualized. In the chemical attachment of the iodine to the water molecule, positive cations are produced as a side effect. Non-ionic does not mean that the contrast media contain no iodine; rather, it means that non-ionic contrast media contain no positive cations to disrupt the balance of the blood plasma. The immune system does not recognize it as foreign matter and is usually not aroused (BIO 316V Module 2 Lecture, 2012).

References:
American Cancer Society, 2013. Retrieved on September 6, 2013 from http://www.cancer.org/treatment/understandingyourdiagnosis/examsandtestdescriptions/i magingradiologytests/imaging-radiology-tests-xrays
BIO-316V Module 2 Lecture, 2012. Grand Canyon University.
Drug Classifications, 2013. Anthem Education. Retrieved on September 6, 2013 from http://www.anthem.edu/pharmacy-technician-school/drug-classifications/

References: American Cancer Society, 2013. Retrieved on September 6, 2013 from http://www.cancer.org/treatment/understandingyourdiagnosis/examsandtestdescriptions/i magingradiologytests/imaging-radiology-tests-xrays BIO-316V Module 2 Lecture, 2012. Grand Canyon University. Drug Classifications, 2013. Anthem Education. Retrieved on September 6, 2013 from http://www.anthem.edu/pharmacy-technician-school/drug-classifications/