Action

Uses

Penicillins were first used on a wide scale in the 1940’s and were the main antibiotics for many years. Penicillin is the broad-spectrum drug of choice for susceptible gram-positive and gram-negative organisms. Penicillins are considered the safest antibiotics.

There are many penicillin products, including oral amoxicillin to injectable procaine penicillin. The choice of drug to give a patient depends on the infectious bacteria (as identified by cultures or smears) or on the basis of the clinical picture. Penicillin is effective in the treatment of the following susceptible organisms: alpha-hemolytic streptococci; group A beta-hemolytic streptococci; streptococci belonging to groups C, G, H, L, and M; and Spirillum minus (rat-bite fever), Treponema pallidum (syphilis), Clostridium perfringens, Clostridium tetani, Corynebacterium diphtheriae, Staphylococcus, Pasteurella meningitidis, and other less common organisms. Penicillin is also used for prophylactic (preventive) treatment against bacterial endocarditis in patients with rheumatic or congenital heart disease before they have dental procedures or surgery of the upper respiratory tract, genitourinary tract, or GI tract. Some penicillins may be useful against organisms used by terrorists as bioweapons.

As broad spectrum antibiotics, penicillin has been used for almost every type of infection, including those for which they were not effective. Over the years, overuse and inappropriate use of penicillin has led to the development of penicillin-resistant strains of disease. These penicillin-resistant strains of bacteria produce a chemical called penicillinase. β-lactamase (penicillinase) is an enzyme that disrupts the internal structure of penicillin and thus destroys the antimicrobial action of the drug. Although penicillin continues to be an important antibiotic, research on penicillin has led to the identification of many other types of antibiotics that may now be used to control infection.

Adverse Reactions

Adverse reactions to penicillin are many. Major reactions include neuropathy (nerve damage in a variety of places and seen with high parenteral dosages), fixed drug eruptions (usually a single spot that itches), nausea, vomiting, epigastric distress, anemia, and blood dyscrasias. Allergy to penicillin has also become a problem, producing rash, erythema (redness or inflammation), urticaria (hives), angioedema (swelling of the skin and mucous membranes), laryngeal edema (swelling of the larynx), and anaphylaxis (shock). These allergic reactions may occur suddenly or after the patient has been taking the medicine for some time and may be life threatening. They may occur up to 10% of the time in patients taking penicillin products.

Drug Interactions

Other bacteriostatic antibiotics such as tetracycline and erythromycin may decrease the bactericidal effect of penicillin. Probenecid prolongs blood levels of penicillin by blocking its renal clearance. Use of ampicillin and oral contraceptives together has produced menstrual irregularities and unplanned pregnancies because penicillin reduces the level of available hormone. Indomethacin, phenylbutazone, or aspirin may increase serum penicillin levels. Antacids may decrease the absorption of penicillin. Penicillin may change the results of some laboratory tests. For example, penicillin may cause increased bleeding time when the platelet count is normal, giving a false positive urine protein test and lupus erythematosus cell test.

Nursing Implications and Patient Teaching

The patient in need of antibiotic therapy may vary from being asymptomatic (showing no symptoms) to being severely ill. Look for common clues to infection, such as fever, redness, swelling, or pain.

Ask whether there is a prior history of penicillin allergy, asthma, or hypersensitivity (allergy) to procaine or tartrazine, and find out if the patient is pregnant or breastfeeding. These conditions may be contraindications or precautions to the use of penicillin. Anaphylactic (shock) reactions have occurred with both oral and parenteral penicillin therapy. Penicillin should be used with caution in patients who have many other drug allergies.

With intramuscular (IM) injections, follow institutional policy about whether to aspirate (pull back on the plunger of the syringe to check for blood) to prevent medicine from accidentally being injected into a blood vessel.

Patients often spread infections to family or friends. For example, the sexual partners of patients infected with syphilis or gonorrhea must be treated also.

Penicillin changes the results of many laboratory tests, so while the patient is on penicillin therapy, the results of laboratory culture and sensitivity tests, as well as many other laboratory findings, may be incorrect.

Action

The tetracyclines are bacteriostatic agents. They act by interfering with the ability of the bacterial to make protein. Without this protein, the bacteria cannot stay alive.

Uses

Adverse Reactions

The tetracyclines are relatively safe, with very few serious adverse effects. They commonly produce mild episodes of nausea, vomiting, and diarrhea that may require stopping the drug. These effects are often dose related, and they result from GI irritation, changes in the normal bacteria in the bowel, and overgrowth of yeast.

The use of tetracycline in pregnancy and in children younger than 8 years of age may produce permanent yellow-brown tooth discoloration or inadequate bone or tooth development.

Photosensitivity may occur with tetracycline treatment, so the patient should avoid exposure to the sun or ultraviolet rays. Pregnant women should not use tetracyclines because they are category D agents which may damage the fetus.

Tetracycline should be used with caution in patients with poor liver function, because the drug may cause hepatotoxicity.

Superinfections may develop, particularly after long-term use. These reactions, such as diarrhea, oral thrush (Candida infection of the mouth), or vaginal itching, are usually irritating but mild. At other times, the superinfection may become life threatening. Overgrowth of organisms is commonly seen in AIDS patients, whose immune systems may be totally overwhelmed by a mild superinfection.

Vertigo may develop with the use of any of the tetracyclines; however, vertigo is more common with the use of minocycline.

Drug Interactions

Patients should not drink milk or take any dairy or calcium while taking these medications. Tetracyclines bind with calcium and iron and may reduce the drug’s absorption up to 50%. Tetracycline is best taken with water on an empty stomach 1 hour before eating or 2 hours after eating.

Nursing Implications and Patient Teaching

Tetracycline products that are out of date (older than the expiration date on the label) should not be used, because it may lead to damage of the proximal renal tubules.

Doxycycline (Vibramycin) is a particularly good drug, especially for the older adult population because it may be taken twice daily and is usually tolerated even by some individuals who have reduced renal function.

Action

Macrolides such as erythromycin are either bacteriocidal or bacteriostatic depending on the organisms and the dose used. Marcolides weaken the bacteria by limiting the production of protein, which is essential to the life of the bacteria.

Uses

The macrolides are used as alternatives to penicillin for many infections for which organisms have developed penicillin resistance. They are the drugs of choice in Streptococcus infections, Haemophilus influenza, Mycoplasma pneumoniae, and Chlamydia infections. They are also used in legionnaires disease and in the treatment of pertussis (“whooping cough”).

Adverse Reactions

Macrolides are associated with very few serious side effects. They are often considered a safe first choice for patients with uncomplicated infection. Mild abdominal pain, nausea, and diarrhea are the most common effects. Watch for signs of superinfection.

Nursing Implications and Patient Teaching

The major differences between erythromycin and the newer macrolides include better GI tolerability, a broader spectrum of activity, and less dosing frequency for the newer products. Giving the medication with food reduces GI irritation.

Caution should be used when this drug is given with any other medication because of the risk of drug-drug interactions and increase of adverse effects.

The strength of erythromycin varies by product. The strength of different products are reported as the erythromycin base equivalence. Because of differences in absorption, 400 mg of ethylsuccinate is required to provide the same free erythromycin serum levels as 250 mg of erythromycin base, stearate, or estolate. This accounts for the differences in doses of different erythromycin products.

Many macrolides may be administered orally or parenterally. Topical application should be avoided to prevent sensitization. The patient should be kept well hydrated (supplied with fluids). Drinking extra fluids to ensure a minimum urine output of 1500 mL decreases the chances of renal toxicity.

All chewable forms of erythromycin must be fully chewed to obtain the complete therapeutic effect.

Action

Aminoglycosides weaken the bacteria by limiting the production of protein, which is essential to the life of the bacteria.

Uses

These products, such as gentamycin and amikacin, are used in the treatment of serious aerobic gram-negative infections, including those caused by Escherichia coli, Serratia, Proteus, Klebsiella, and Pseudomonas; aerobic gram-negative bacteria, mycobacteria, and some protozoans. Streptomycin (SM) is used in the treatment of TB. Some products are used to sterilize the bowel before intestinal surgery.

Adverse Reactions

Aminoglycosides may cause serious adverse effects including damage to the kidney (nephrotoxicity) that is usually reversible if the drug is stopped quickly. They may also produce permanent damage to the inner ear (ototoxicity), hearing impairment, dizziness, loss of balance, ringing in the ears, and persistent headache. Aminoglycosides have a narrow therapeutic range, so the blood levels of these drugs should be closely watched to avoid toxic levels. Dosage is calculated on the basis of the patient’s weight and is increased or decreased based on blood levels so an effective level is maintained. The narrow therapeutic range (when the lowest and highest acceptable drug levels are not far apart) requires that the sample for the antibiotic blood level be drawn just before the next scheduled dose is given. This sample will show the lowest blood level of the antibiotic (found at the “trough”), rather than a blood level at a higher range (at or near the “peak”). The lowest blood level will determine whether the dosage needs to be adjusted to stay within the therapeutic range and not go above the toxic level or below the effective level. Because of the nephrotoxicity of these agents, blood urea nitrogen and creatinine levels must also be monitored during the course of therapy.

Drug Interactions

Using this drug with many products, particularly vancomycin, increases the risk of nephrotoxicity. Ototo­xicity is also increased with aspirin, furosemide, ethacrynic acid, and many other drugs.

Nursing Implications and Patient Teaching

Some of these products are available over-the-counter (OTC) or by prescription for eye, ear, or skin infections. When given for systemic bacterial infections they must be given parenterally as they are poorly absorbed from the GI tract.

Patients should have frequent hearing and urine tests to monitor for nephrotoxicity and ototoxicity.

Action

Fluroquinolones are bacteriocidal and act by interfering with bacterial DNA synthesis, which makes it difficult for the pathogens to reproduce themselves and attack other cells.

Uses

There are four generations of fluoroquinolones, which are all effective against gram-negative pathogens. The newer ones are significantly more effective against gram-positive microbes. These agents are used as alternatives to other antibiotics in the treatment of respiratory, GI, gynecologic, skin, and soft-tissue infections. Ciprofloxin (Cipro) is the drug of choice for anthrax exposure in a bioterrorist attack.

Drug Interactions

Fluoroquinolones should not be taken with multivitamins or mineral supplements because they reduce the absorption of the antibiotic by as much as 90%. When taken with warfarin, fluoroquinolones will increase warfarin’s anticoagulant effects. Antacids and ferrous sulfate may decrease absorption of the drugs. Patients may develop excessive nervousness, anxiety, or tachycardia if taken with coffee or other caffeine-containing products.

Nursing Implications and Patient Teaching

Fluoroquinolones are well absorbed orally and may be given only once or twice per day. Take drug with food to decrease adverse GI effects.

Action

Cephalosporins are bactericidal and weaken the bacteria by interfering with building of the bacteria’s cell wall.

Uses

There are four generations of cephalosporins, all of which have broad spectrum activity against gram-negative organisms. In general, second- and third-generation drugs are more effective and more potent than first-generation agents against a broad group of gram-negative organisms; however, they are also less effective against gram-positive organisms. Third-generation agents are also more effective against inact­ivation by beta-lactamase (an enzyme that some organisms make to protect them against the action of some antibiotics). However, these agents cost more and may have more side effects. Differences among drugs within categories are primarily based on the drug’s activity. Later-generation drugs are more effective against some of the organisms to which earlier generation agents have been resistant.

Cephalosporins are used for serious infections, like bacteremia and septicemia (infections of the blood); and infections of the lower respiratory tract, central nervous system (CNS), genitourinary system, joints, and bones. These drugs are also used in patients who cannot take penicillin.

Adverse Reactions

Nausea, vomiting, and diarrhea are frequent. The most common adverse effect is acute hypersensitivity. Although some patients may have only a minor rash and itching, anaphylaxis is possible. There may be severe pain at the injection site. Nephrotoxicity has been reported with some cephalosporins, and the incidence is greater in older adult patients and in patients with poor renal function.

Drug Interactions

Alcohol taken with these products may produce a severe disulfiram reaction resulting in severe flushing, vomiting, and collapse. Other products, such as probenecid, may decrease elimination of the drugs by the kidneys.

Nursing Implications and Patient Teaching

Must be given by the IV or IM route because it is not absorbed from the GI tract.

Patients who have had a recent and severe reaction to penicillin should not be prescribed these products.

Action

Sulfonamides have a bacteriostatic effect against a wide range of gram-positive and gram-negative microorganisms by inhibiting folic acid synthesis, which is essential for cell growth and function.

Uses

Sulfonamides are usually used to treat acute and chronic urinary tract infections, particularly cystitis, pyelitis, and pyelonephritis caused by E. coli or Nocardia asteroides. Other indications include toxoplasmosis, acute otitis media caused by H. influenzae, and preventive therapy in cases of recurrent rheumatic fever. Susceptible organisms include Streptococcus pyogenes, Streptococcus pneumoniae, some strains of Bacillus anthracis, C. diphtheriae, Haemophilus ducreyi, Chlamydia trachomatis, and other less common organisms. Several sulfonamides are useful only in the treatment of ulcerative colitis, and as preoperative and postoperative therapy for bowel surgery.

Adverse Reactions

Adverse reactions to sulfonamides include many minor but irritating problems such as headache, drowsiness, fatigue, dizziness, vertigo (feeling of dizziness or spinning), tinnitus (ringing in the ears), hearing loss, insomnia (inability to sleep), anorexia (lack of appetite), nausea, vomiting, stomatitis (inflammation of the mouth), abdominal pain, rash, fever, malaise (weakness), pruritus (itching), dermatitis, local irritation, anaphylactic shock, crystalluria (formation of crystals in the urine), hematuria (blood in the urine), and proteinuria (large amounts of protein in the urine) may develop with overdosage and indicate that the patient may have a severe hypersensitivity to sulfonamides.

Drug Interactions

Sulfonamides may increase the effect of oral anticoagulants, methotrexate, sulfonylureas, thiazide diuretics, phenytoin, and uricosuric agents. Many other drugs taken at the same time will cause the effects of sulfonamides to be increased. Penicillins may be less effective when given with a sulfonamide. The sulfonamide’s effect may be decreased by local anesthetics. Antacids may cause less absorption of the sulfonamide. Sulfonamides may change the results of various laboratory tests including urine glucose.

Nursing Implications and Patient Teaching

Warn the patient to stay out of the sun, because severe photosensitivity (abnormal response to exposure to sunlight) can occur if the patient’s skin is exposed to excessive amounts of sunlight or ultraviolet light.

Sulfonamide dosage depends on the severity of the infection being treated, the drug used, and the patient’s response to and tolerance of the drug. Generally, the short-acting sulfonamides are given at more frequent intervals than are the intermediate- or long-acting sulfonamides. Also, short-acting sulfonamides usually require a special first dose (initial loading dose) that is larger than the dose that will be regularly taken.

Sulfonamides are more fully and quickly absorbed when they are taken on an empty stomach. They should be taken either 1 hour before or 2 hours after meals, along with a full glass of water.

To prevent formation of crystals in the urine, the patient must drink large amounts of water while taking this medication.

It is particularly important with these drugs that the patient should take all the medication prescribed and not stop just because the symptoms have disappeared, so they do not have a relapse.

The health care provider should be notified quickly if a skin rash, blood in the urine, bruises, nausea, or other adverse effects of therapy develop because these may indicate development of more severe reactions.

Action

Carbapenem is a broad-spectrum antibiotics are effective against gram-positive and gram-negative bacteria. They penetrate bacterial cells and interfere with the making of vital cell wall parts, which leads to cell death, making them bactericidal.

Uses

Carbapenem is used in acute infections caused by bacterial meningitis, intraabdominal infections, skin, and skin structure infections.

Adverse Reactions

Carbapenem may produce pseudomembranous colitis, hypersensitivity reactions, and impaired renal function.

Nausea, vomiting, diarrhea, headache, rash, sepsis, constipation, apnea, shock, and pruritus were all reported.

Drug Interactions

Carbapenem competes with probenecid, so these drugs should not be given at the same time. The drug may reduce the activity of valproic acid, which is given to prevent seizures.

Nursing Implications and Patient Teaching

Carbapenem is administered intravenously. Reduced dose is required in patients with reduced kidney function. Watch for adverse effects, as they are frequent.

Action

This drug is bacteriocidal, inhibiting the building of the bacterial cell-wall.

Uses

Adverse Reactions

May be associated with minor hypersensitivity reactions or anaphylaxis. This drug causes frequent but minor side effects such as rash on the upper body (red-man syndrome), flushing, and hypotension. Higher doses may produce nephrotoxicity and ototoxicity.

Drug Interactions

This drug adds to the toxicity of other antibiotics such as the aminoglycosides, and other products that are ototoxic or nephrotoxic. Cholestyramine and colestipol decrease the absorption of the drug.

Nursing Implications and Patient Teaching

Nursing Implications and Patient Teaching for Antibiotics in General

Action

The main action of antitubercular drugs take place both within or outside the cell wall of the bacteria that slow down the M. tuberculosis bacteria. Most drugs used to treat TB do not kill the bacterium, but they control the disease and prevent its spread to various organ systems in the infected patient or to other individuals. The drugs control the bacteria by preventing them from producing new cell walls, so new bacterial cell growth is limited. Some antitubercular drugs are bactericidal, killing the organism.

Uses

Adverse Reactions

Mycobacterium tuberculosis is able to build up a resistance to antitubercular drugs. Use of a combination of drugs helps slow the development of bacterial resistance. Most of the antitubercular medications cause only mild and infrequent symptoms such as nausea, vomiting, and diarrhea. Most of these symptoms stop when the dosage is reduced. Some of the drugs used to treat TB are toxic to various parts of the body (for example, the ears, kidneys, and liver). The patient must be watched closely to detect development of any of these more serious problems. All drugs are associated with some adverse reactions. Those for treating TB have many adverse reactions in the body. The most common or most serious are briefly described in the following text.

Capreomycin may cause headache, ototoxicity (hearing loss, tinnitus, vertigo), nephrotoxicity, abnormal liver function tests, maculopapular rash associated with febrile reaction, urticaria, muscle weakness, pain and swelling or excessive bleeding at the injection site, and sterile abscesses.

Ethambutol (EMB) is associated with dizziness, headache, confusion, dermatitis, abdominal pain, anorexia, nausea, vomiting, joint pain and swelling, optic neuritis (loss of vision), and loss of visual acuity.

Ethionamide may produce severe postural hypotension (low blood pressure when a person suddenly stands or sits up), mental depression, rash, anorexia, diarrhea, epigastric distress, jaundice, nausea, and vomiting.

INH is one of the most frequently used drugs. It may produce many neurologic disturbances in sensation and vision, as well as variable changes in electrolytes. As with many drugs, nausea, constipation, epigastric distress, and vomiting are common. Severe and sometimes fatal hepatitis may develop, even after many months of treatment. The drug also changes the results of a variety of laboratory tests. Symptoms of overdosage may occur any time from 30 minutes to 3 hours after the INH is administered. Nausea, vomiting, slurred speech, dizziness, impaired vision, and visual hallucinations may be among the early symptoms. Severe overdosage results in CNS depression, respiratory distress, coma, and severe intractable seizures.

Pyrazinamide (PZA) has been associated with photosensitivity, rashes, diarrhea, hepatocellular damage, nausea, vomiting, gout, decreased blood clotting time, and anemia.

Rifampin (RIF) may cause drowsiness, headache, generalized numbness, transient low-frequency hear­ing loss, visual disturbances, abdominal pain or cramps, diarrhea, epigastric distress, hepatitis, nausea, sore mouth and tongue, vomiting, and changes in blood cells. Symptoms of overdosage include nausea, vomiting, increasing lethargy, unconsciousness, liver enlargement and tenderness, and jaundice. RIF also turns the urine a reddish-orange color.

SM sulfate may produce dizziness, headache, paresthesias (numbness or tingling), vertigo, anorexia, nausea, stomatitis, vomiting, changes in blood cells, arthralgia (joint pain), hypertension (high blood pressure), hypotension (low blood pressure), myocarditis, hepatotoxicity, splenomegaly (enlarged spleen), ototoxicity, and nephrotoxicity.

Drug Interactions

The drug treatment plan for TB is often complicated. No other drugs should be taken at the same time or right after antitubercular drugs are swallowed, or put on the skin while the patient is on antituberculosis therapy. This is because other drugs may increase the significant risk for neurotoxicity and nephrotoxicity. All drugs taken by the patient should be checked closely for drug interactions, which are very common among the antitubercular drugs.

Nursing Implications and Patient Teaching

Action

There are a wide variety of parasites and thus a wide variety of drugs used to treat them. Amebiasis is often caused by the parasite Entamoeba histolytica. In the United States and Canada, this infection is seen primarily in people who have traveled abroad. It is also found in those who have eaten unwashed fruits or vegetables imported from other countries, so parasitic infection could be common. The main action of an amebicide is to destroy the invading amoeba, which may be located within the GI tract or some other place in the body (extraintestinal). Infections outside the intestinal tract are much more difficult to treat. The most common extraintestinal infection is a hepatic abscess.

Uses

Amebicides are the primary therapy for both intestinal and extraintestinal amebiasis. The choice of drug depends on the location of the infection.

Diiodohydroxyquin and metronidazole are also used to treat Trichomonas vaginali and giardiasis, which is commonly found in drinking water, particularly in other countries.

Adverse Reactions

All drugs used to treat amebiasis may cause nausea, vomiting, headache, anorexia, diarrhea, or GI distress.

Chloroquine may produce dizziness, irritability, pruritus, ototoxicity, tinnitus, vertigo, visual disturbances, or abdominal cramps.

Diiodohydroxyquin has been known to cause ataxia (poor coordination), neurotoxicity, peripheral neuropathy, optic neuritis, abdominal cramps, rectal and skin itching, constipation, and hair loss.

Paromomycin may produce vertigo, rash, ototoxicity, abdominal cramps, constipation, hematuria, and nephrotoxicity.

Symptoms of overdosage are also seen with all of these drugs and are an exaggeration and increase of the adverse effects.

Drug Interactions

With the exception of metronidazole, there are no significant drug interactions. Combining metronidazole with alcohol can produce severe headache, flushing, cramps, nausea, and vomiting. Collapse or acute psychosis may result.

Nursing Implications and Patient Teaching

Action

When a patient has worms, the infestation is called helminthiasis. The condition is usually caused by pinworms, roundworms, hookworms, tapeworms, or whipworms. The worm gains entrance to the body through unclean food, unwashed hands, or the skin. The diagnosis is made by finding the eggs or the parasite in the stool of the infected individual. Once the type of parasite has been identified, the health care provider may order the best medication for its destruction. The way the drug works depends on the product used.

The exact action of diethylcarbamazine citrate as an anthelmintic is not known. It is thought that it sensitizes the parasite’s cuticle to allow phagocytosis by the macrophages of the host. Mebendazole blocks the glucose uptake of helminths. Piperazine paralyzes the muscles of parasites by blocking the effects of acetylcholine at the neuromuscular junction, and the parasite is removed by normal peristalsis during the bowel movement. The exact action of thiabendazole is not known, but it is thought to interfere with metabolic pathways essential for a variety of helminths.

Uses

Thiabendazole is the drug of choice for cutaneous larva migrans (creeping eruption), pinworms, roundworms, Strongyloides, and mild cases of hookworm.

Niclosamide and paromomycin are used to treat cestodiasis (tapeworm infestation).

Piperazine and pyrantel pamoate are used to treat roundworms and pinworms. Pyrantel is also effective against hookworms.

Diethylcarbamazine citrate is used mostly in tropical areas or in patients who have been in areas where these worms are endemic. It is used to treat Bancroft filariasis, Malayan filariasis, dipetalonemiasis, or infestation with loiasis (a filarial worm dwelling in tumors in subcutaneous connective tissue and often affecting the eyes).

Mebendazole is used in single or mixed infections to treat pinworm, roundworm, hookworm, and whipworm infestations.

Adverse Reactions

Each drug has different side effects. Headache, weakness, anorexia, nausea, vomiting, abdominal pain, arthralgia, lassitude (weariness), malaise, myalgia (widespread muscle pain), and skin rash are all common reactions. Allergic reactions may occur as a result of the dead microfilaria and may be seen with fever, lymphadenitis (inflammation of the lymph nodes), pruritus, and pedal edema (foot swelling). The number of side effects increases with higher dosages and longer length of treatment.

Drug Interactions

Anthelmintic drugs work against each other (antagonistic) if they are given together. The drugs also may interfere with a number of specific drugs, such as heparin, and a variety of laboratory tests. Specific product information should be consulted for each drug.

Action

Malaria is a big problem in many countries where wetlands provide a good breeding ground for mosquitoes. Patients with malaria have periods of acute sickness followed by periods during which they are symptom free. The antimalarial drugs suppress the infection but often do not cure it. Although malaria is not commonly seen in the United States or Canada, it is becoming more frequent in Florida, other areas of the southern United States, and areas adjoining Mexico. The nurse may also see cases among immigrants, migrant farm workers, and travelers returning from areas where malaria is endemic (occurs in a regular pattern). People in the military or those traveling to or living in areas where malaria is endemic can use antimalarials to prevent malaria and treat the symptoms.

Malaria is caused by four species of the protozoan Plasmodium. These species are P. falciparum, P. malariae, P. vivax, and P. ovale. The protozoan parasites are transmitted to humans by the Anopheles mosquito.

When a mosquito bites a person infected with malaria, the protozoans enter the mosquito’s stomach, where they reproduce. The resulting sporozoites make their way to the salivary glands of the mosquito. They are then transmitted to other individuals whenever the mosquito bites. The sporozoites grow and divide in the human host, entering the red blood cells of the person and maturing into the adult form of the protozoan, which then produces infection and the symptoms of malaria.

Uses

Antimalarials are used to suppress and treat acute malaria attacks caused by erythrocytic forms of P. ovale, P. malariae, P. vivax, and most strains of P. falciparum. The 4-aminoquinoline drugs are ineffective against the gametocytes of P. falciparum but are used with primaquine to cure malaria caused by P. malariae and P. vivax.

Adverse Reactions

Synthetic 4- and 8-aminoquinolines may produce hypotension, electrocardiogram (ECG) changes, mild and transient headaches, pruritus, abdominal cramps, anorexia, diarrhea, nausea, vomiting, blood dyscrasias, visual blurring, reduced hearing, and tinnitus.

Folic acid antagonists may produce anorexia, atrophic glossitis (loss of papillae of the tongue), vomiting, and anemias.

Quinine poisoning is called cinchonism and causes diarrhea, dizziness, headache, nausea, tinnitus, visual blurring, fearfulness, confusion, excitement, hypothermia (abnormally low body temperature), syncope (light-headedness and fainting), abdominal cramps, vomiting, anemias, pruritus, rash, urticaria, and night blindness.

All of these drugs may sometimes produce blood dyscrasias, as well as visual and neurologic changes. Overdose may produce convulsions and cardiac collapse.

Drug Interactions

Use of any antimalarials with other drugs that cause dermatologic, ototoxic, or neurologic symptoms may produce toxicity. There are isolated drugs that interact with these preparations, so read the manufacturers’ information carefully.

Nursing Implications and Patient Teaching