Ebook The gale encyclopedia of prescription drugs: Part 2

M Macrobid see Nitrofurantoin Maxalt see Rizatriptan Mebendazole Definition Mebendazole is an anthelmintic drug used to treat infections with parasites, such as worms. It is considered a broad-spectrum agent, meaning that it has activity against a wide variety of parasites. Purpose Mebendazole is used to treat infections with many types of worms, including: U.S. brand names Mebendazole is no longer available in the United States. Canadian brand names Mebendazole is sold under the brand name Vermox in Canada. International brand names Mebendazole is sold in many countries worldwide under a variety of names, including Wormex (South Africa), Versid (Turkey), Vermicide (Taiwan), Tesical (Argentina), Sufil (Spain), and Ovex (United Kingdom). In some countries, mebendazole is only one component of the medication, and there are other medications included in the formulation. In some locations, it is only available for veterinary, not human, use. � roundworms (Ascaris lumbricoides) � hookworms (Ancylostoma duodenale and Necator americanus) � pinworms (Enterobius vermicularis) � whipworms (Trichuris trichiura) � tapeworms (Taenia solium) Recommended dosage For roundworm, hookworm, whipworm, or tape-worm, the recommended dosage for adults who are treated with mebendazole is 100 mg twice daily for three days. If the infestation is not cured, then this regimen should be repeated in three weeks. Mebendazole can also treat infections with more than one type of a worm at a time. Description Mebendazole is a flat, round, orange tablet that is 10 millimeters (mm) in size. It is imprinted on one side with the numbers 93 and 107. Each pill contains 100 milligrams (mg) of active drug. The medication is taken by mouth and must be prescribed by a physician. Mebendazole is on the World Health Organization’s list of essential medicines. It is also frequently used in veterinary medicine. GALE ENCYCLOPEDIA OF PRESCRIPTION DRUGS For pinworm, the recommended dosage for adults who are treated with mebendazole is a single 100 mg dose. This should be repeated after two weeks and again after four weeks. Family members who have close contact with the patient should also be treated with the same regimen. Mebendazole is taken by mouth and may be taken whole, crushed, or chewed. It may be taken with or between meals. Pediatric For children over the age of two, the adult dosage recommendations may be used. 553 KEY TERMS Ovex (mebendazole), 100 mg. (Finnbarr Webster/Alamy) Precautions Mebendazole should be taken for the entire length of the prescription. Mebendazole can lead to bone marrow suppression when used at high doses or for long periods of treatment. Pediatric The safety and effectiveness of mebendazole in children under the age of two have not been established. Seizures have been reported when mebendazole is used in infants under a year old. Pregnant or breastfeeding Mebendazole carries the FDA pregnancy category C, meaning that risk to the fetus cannot be ruled out in pregnant individuals. If possible, use of this drug should be delayed until the third trimester. Small amounts of mebendazole may pass into breast milk but are unlikely to affect the nursing infant. Other conditions and allergies Mebendazole should not be taken by individuals who are hypersensitive to mebendazole, benzimidazoles, or any other ingredient of the preparation. Individuals with a history of liver problems should inform their healthcare provider prior to starting the medica-tion,andcareshouldbetakenwhiletakingtheprescription. Side effects Side effects of mebendazole treatment include: • upset stomach or abdominal pain, sensation of indiges-tion, nausea, vomiting, diarrhea • hair loss • itching, rash, hives 554 Anthelmintic—A drug that is used to treat an infection with parasitic worms. Parasite—A type of organism that survives within another living host and nourishes itself by using that host’s energy stores without providing the host with any benefit. Roundworm—A type of worm with a long body that lives in the intestines of mammals. Tapeworm—A type of flatworm that has many segments and lives within the intestines of its hosts, which can include humans and other animals that have backbones (vertebrates). • headache, dizziness, drowsiness • seizures • bloodtestevidenceofbonemarrowsuppression,including low white blood count, low platelets, or low hematocrit • blood test evidence of liver damage • blood test evidence of kidney damage • blood in the urine • yellow cast to skin and/or whites of eyes Rare but serious signs of a significant allergic reaction to mebendazole should prompt the individual to seek immediate medical care. These include: • difficulty breathing • wheezing • fever • cough • blue skin or lips • seizures • swollen face, lips, tongue, or throat Interactions Pharmaceutical drugs may interact with other pharmaceuticals, herbs, dietary supplements, and foods. Drug interactions can increase or decrease the effective-ness of the drug or increase the risk of serious side effects. Patients should tell the prescribing doctor about all the medications they are taking, including nonpre-scription (over-the-counter) medications, herbs, and die-tary supplements, including vitamin supplements. Drugs Drugs that may decrease the amount of mebendazole in the bloodstream include antimalarial drugs such as GALE ENCYCLOPEDIA OF PRESCRIPTION DRUGS aminoquinolines, carbamazepine, fosphenytoin, and phenytoin. Cimetidine may increase the amount of mebendazole in the bloodstream. Close monitoring is recommended when these drugs are used together. Using mebendazole and metronidazole at the same time can increase the risk of severe toxic effects from the metronidazole. It is recommended to avoid using these drugs at the same time. Resources BOOKS Bennett, John E., Raphael Dolin, and Martin J. Blaser. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 8th ed. Philadelphia: Saunders, 2014. Cherry, James, et al. Feigin and Cherry’s Textbook of Pediatric Infectious Diseases. 7th ed. Philadelphia: Saunders, 2014. Lexicomp. Drug Information Handbook. 23rd ed. Hudson, OH: Lexicomp Inc., 2014. Magill, Alan, et al. Hunter’s Tropical Medicine and Emerging Infectious Diseases. Philadelphia: Saunders, 2013. Rang, Humphrey, et al. Rang and Dale’s Pharmacology. 7th ed. London: Churchill Livingstone, 2012. Resources WEBSITES “Mebendazole.” Drugs.com. http://www.drugs.com/mtm/ mebendazole.html (accessed February 19, 2015). MedlinePlus. “Mebendazole.” U.S. National Library of Medi-cine, National Institutes of Health. http://www.nlm.nih .gov/medlineplus/druginfo/meds/a682315.html (accessed February 19, 2015). U.S. National Library of Medicine. “LactMed: Mebendazole.” TOXNET. http://toxnet.nlm.nih.gov./cgi-bin/sis/search2/r? dbs+lactmed:@term+@DOCNO+465 (accessed February 19, 2015). ORGANIZATIONS American Society of Health-System Pharmacists (ASHP), 7272 Wisconsin Avenue, Bethesda, MD 20814, (866) 279-0681, http://www.ashp.org/. U.S. Food and Drug Administration (FDA), 10903 New Hampshire Avenue, Silver Spring, MD 20993, (888) INFO-FDA (463-6332), http://www.fda.gov/. Rosalyn Carson-DeWitt, MD REVIEWED BY KEVIN GLAZA, RPH Meclizine Definition Meclizine is an antihistamine commonly used to control nausea, vomiting, and dizziness. GALE ENCYCLOPEDIA OF PRESCRIPTION DRUGS Meclizine, 12.5 mg. (Reprinted with permission. Copyright 1974–2015 Truven Health Analytics Inc. All rights reserved.) Purpose Meclizine may be given to help control nausea and vomiting that often occurs with cancer treatment, other medical conditions, or motion sickness. It is also used as part of palliative care for patients with terminal cancer. Description Meclizine acts as a central nervous system depres-sant. It is believed its therapeutic actions occur due to the drug’s drying effects and its ability to depress conduction of nerve messages in the inner ear. Meclizine begins working about one hour after ingestion. It continues being effective for 8 to 24 hours. U.S. brand names In the United States, the prescription brand name of meclizine is Antivert. It is also sold over the counter as Bonine. Recommended dosage When used to manage dizziness, such as the dizziness that occurs with vertigo, patients generally take 25–100 milligrams (mg) daily in divided doses. The dosage to control nausea and vomiting associated with cancer treatment is 25–50 mg, every 8 to 12 hours. Patients should not double up on this medication if a dose is missed. 555 KEY TERMS Antihistamine—Agent that blocks or counteracts the action of histamine, which is released during an allergic reaction. Central nervous system depressant—Any drug that lowers the level of stimulation or excitement in the central nervous system. Palliative—Referring to treatments that are intended to relieve pain and other symptoms of disease but not to cure. Vertigo—The sensation of moving around in space, or objects moving around a person. It is a disturbance of equilibrium. Precautions Meclizine may cause drowsiness and fatigue. Drowsiness is the most common adverse reaction. Alcohol and other central nervous system depressants, such as pain medication and tranquilizers, may increase this effect. Patients should refrain from drinking alcoholic beverages and avoid driving or operating machinery or appliances when taking this drug. Pediatric The FDA recommends that children under age 12 do not take this drug, except under the direction of a physician. Pregnant or breastfeeding Pregnant women and those trying to become pregnant should not take this medication. Animal reproductive studies have shown some deformities at elevated doses. Women who are breastfeeding should discuss this medication with their doctors prior to taking it. Other conditions and allergies Patients with glaucoma, an enlarged prostate, bladder or bowel obstructions, or asthma or other breathing difficulties should discuss with the doctor the risks and benefits associated with this drug before taking it. Those who have experienced an allergic reaction to meclizine should not take it. Side effects Meclizine sometimes produces excitability, nervous-ness, restlessness, mood enhancement, or difficulty 556 sleeping. Rarely, it may cause a patient to see or hear things that are not present (hallucinations). Despite being used to treat nausea and vomiting, it may produce these effects. It may also cause constipation, diarrhea, an upset stomach, or a loss of appetite. Other side effects include frequent or difficult urination, incomplete emptying of the bladder, low blood pressure, and a rapid heart rate or palpitations. It may cause vision changes, a dry nose and throat, ringing in the ears, and a rash or hives. Side effects may decrease as the body adjusts to the medication. Ice chips or sugarless hard candy or gum may help relieve dry mouth. If the feeling of a dry mouth persists for more than two weeks, the doctor should be notified. Geriatric Some of the side effects may be more pronounced in older adults. Interactions Patients should inform their doctor of all medica-tions they are currently taking and should not start or stop any drugs without physician approval. Drugs Central nervous system depressants may increase drowsiness associated with meclizine. Pain medications, other antihistamines, seizure medications, sleeping pills, and muscle relaxants can depress the central nervous system. Taking this drug with some medications used to treat depression may increase the risk of side effects. Herbs and supplements The herbal supplement henbane may increase some of meclizine’s side effects, including dry mouth and difficulty urinating. Food and other substances Alcohol can increase the sedative effect of meclizine and should be avoided. Resources PERIODICALS Wang, Z., et al. “Meclizine Metabolism and Pharmacokinetics: Formulation on Its Absorption.” Journal of Clinical Pharmacology 52, no. 9 (2012): 1343–49. WEBSITES A.D.A.M. Medical Encyclopedia. “Meclizine.” University of Maryland, Baltimore Washington Medical Center. http:// www.mybwmc.org/library/41/080100 (accessed February 25, 2015). GALE ENCYCLOPEDIA OF PRESCRIPTION DRUGS Desmond, Alan L., and R. Brian Collie. “Meclizine—Does It Help?” Vestibular Disorders Association. https:// vestibular.org/news/10-07-2013/meclizine-%E2%80%93-does-it-help (accessed February 25, 2015). Lexi-Comp. “Meclizine.” Merck Manual Professional Edition. http://www.merckmanuals.com/professional/lexicomp/ meclizine.html (accessed February 25, 2015). Physicians’ Desk Reference. “Antivert.” PDR Health. http:// www.pdrhealth.com/drugs/antivert (accessed February 25, 2015). ORGANIZATIONS U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, (888) INFO-FDA (463-6992), http://www.fda.gov/. Vestibular Disorders Association, 5018 NE 15th Avenue, Port-land, OR 97211, (800) 837-8428 (VESTIBU), Fax: (503) 229-8064, info@vestibular.org, https://vestibular.org/. Rebecca J. Frey, PhD REVIEWED BY KEVIN GLAZA, RPH Medrol see Methylprednisolone Medroxyprogesterone Definition Medroxyprogesterone acetate (MPA) is a synthetic derivative of the hormone progesterone. In healthy women, progesterone plays a major role in preparing the uterus for pregnancy. MPA is in a class of medications called progestins. Purpose Medroxyprogesterone acetate (MPA) is used as a contraceptive. MPA is also prescribed to women to restore normal menstrual cycles and to treat abnormal menstruation. It is sometimes used during cancer therapy to stop new cell growth in certain cancers. Off-label uses In males, MPA has been prescribed to control inappropriate sexual behavior by chemically castrating convicted sexual offenders. Description MPA works by changing the consistency of cervical mucus to make it more difficult for sperm to reach the egg, changing the uterine lining to prevent a fertilized egg from implanting in the uterus, and inhibiting ovulation. When used as prescribed, the medication is GALE ENCYCLOPEDIA OF PRESCRIPTION DRUGS Medroxyprogesterone, 150 mg/mL. (Reprinted with permission. Copyright 1974–2015 Truven Health Analytics Inc. All rights reserved.) effective as a form of birth control, though no method is considered 100% effective. Additionally, MPA is used in conjunction with other medications to treat cancers in the endometrium, the lining of the uterus. Many cancerous tumors are sensitive to hormones. It appears that MPA in some way changes the hormonal climate of the tumor so that cells stop responding to other hormones and proteins that would normally stimulate their growth. This drug cannot specifically target cancer cells, so some normal cells are also killed during treatment. However, since cancer cells generally grow more rapidly than normal cells, more cancer cells are killed. MPA is considered very effective and relatively nontoxic. MPAisavailableintabletformandinjectionform.The tablet form is available in strengths of 2.5, 5, and 10 milligrams(mg).Theinjectableformisavailableinstrengths of150mgpermilliliter(mL)and400mg/mL.Theinjectable form must be injected by a healthcare provider in a medical setting; it is not prescribed for home use. U.S. brand names In the United States, MPA is sold under the brand names Depo-Provera and Provera. Canadian brand names In Canada, MPA is sold under the brand names Apo-Medroxy, Depo-Provera, Gen-Medroxy, 557 ... - tailieumienphi.vn