The following are the Drugs used to treat Amebiasis
- Chloroquine
- Dehydroemetine
- Emetine
- Iodoquinol
- Metronidazole
- Paromomycin
- Tinidazole
| Chloroquine |
| Availability: Tablets: 250 mg (150-mg base), 500 mg (300-mg base) |
| Indication & dosage: 1. Uncomplicated acute malarial attacks Adults: Initially, 1 g (600-mg base) P.O., then an additional 500 mg (300- mg base) P.O. 6 hours later and a single dose of 500 mg (300-mg base) P.O. on second and third days. Or initially, 160- to 200-mg base I.M., repeated in 6 hours (800-mg base maximum dosage during first 24 hours); continue for 3 days until total dosage of 1.5-g base has been given. Switch to oral therapy as soon as possible. Children: Initially, 10 mg (base)/kg P.O., then 5 mg (base)/kg 6 hours, 24 hours, and 36 hours later; don’t exceed recommended adult dosage. Or initially, 5 mg (base)/kg I.M. repeated 6 hours later, 18 hours after second dose, and then 24 hours after third dose; don’t exceed recommended adult dosage |
| 2. Malaria prophylaxis Adults: 500 mg (300-mg base) P.O. weekly 1 to 2 weeks before visiting endemic area and continued for 4 weeks after leaving area. If therapy starts after malaria exposure, initial dosage is 600-mg base P.O. in two divided doses given 6 hours apart. Children: 5 mg (base)/kg P.O. weekly for 1 to 2 weeks before visiting endemic area and continued for 4 weeks after leaving area, to a maximum dosage of 300 mg weekly. If treatment starts after exposure, 10 mg (base)/kg P.O. in two divided doses 6 hours apart and continued for 8 weeks after leaving area. |
| 3. Extraintestinal amebiasis Adults: Initially, 1 g (600-mg base) P.O. daily for 2 days, then 500 mg (300-mg base) daily for 2 to 3 weeks. When oral therapy isn’t tolerated, give 160- to 200-mg base I.M. daily for 10 to 12 days, switch to oral therapy as soon as possible. Children: 10 mg (base)/kg P.O. once daily for 2 to 3 weeks, to a maximum dosage of 300 mg (base) daily |
| Mechanism of Action: Unknown. Antimalarial action may occur through inhibition of protein synthesis and alteration of DNA in susceptible parasites |
Metabolism & Elimination:
Metabolism: Partially in liver
Half-life: 3-5 days
Excretion: urine (~70% as unchanged drug); acidification of urine increases elimination
Elimination: Small amounts may be present in urine months following discontinuation of therapy
Contraindications
- Hypersensitivity to drug
- Retinal and visual field changes Porphyria
Precautions:
- Severe GI, neurologic, or blood disorders; hepatic impairment; G6PDdeficiency; neurologic disease; eczema; alcoholism
- Pregnant patients
- Children.
- Administration
- For obese patient, determine weight-based dosages from lean body weight. (Drug is stored in body tissues and eliminated slowly.)
Adverse reactions
CNS: mild and transient headache, personality changes, dizziness, vertigo neuropathy, seizures
CV: hypotension, ECG changes
ENT: blurred vision, difficulty focusing, reversible corneal changes, irreversible retinal damage leading to vision loss, scotomas, ototoxicity, tinnitus, nerve deafness
GI: nausea, vomiting, diarrhea, abdominal pain, stomatitis, anorexia
Hematologic: agranulocytosis, aplastic anemia, hemolytic anemia, thrombocytopenia
Skin: lichen planus eruptions, skin and mucosal pigmentation changes, pruritus, pleomorphic skin eruptions
Patient monitoring
- Monitor hepatic enzyme levels in patients with hepatic disease
- Assess creatinine levels in patients with renal insufficiency or failure.
- In long-term therapy (as for lupus or rheumatoid arthritis), be aware that desired effects may be delayed for up to 6 months.
- Be aware that drug is secreted in breast milk but not in sufficient amounts to prevent malaria in infant.
Patient teaching
- Tell patient to take drug with food at evenly spaced intervals.
- Instruct patient to immediately report blurred vision or hearing changes.
- In areas where malaria is endemic, advise pregnant patient to consult prescriber about taking drug.
- Inform patient on long-term therapy that beneficial effects may take up to 6 months.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, test
| Dehydroemetine |
| Availability: Adults: 1 mg/kg daily, up to a maximum of 60 mg, for up to 4-6 days. Elderly and severely ill patients: Reduction by up to 50% of adult dose. Children: 1 mg/kg daily for no more than 5 days. |
| Indication & dosage: Acute amoebic dysentery Amoebic liver abscess Liver fluke infestation Dose: 0.75 -1 md/kg/day in divided doses IM for 5 days |
| Mechanism of Action: Drug is similar to emetine but with fewer side effects. Inhibits polypeptide chain elongation and mammalian cells. |
| Metabolism & Elimination: Absorption: Rapid absorption after intramuscular administration. Metabolism and Excretion: Slow renal excretion. |
| Contraindications: Polyneuritis, heart disease |
Adverse effects:
- Skin: Abscess formation, eczema like rash
- Neuromuscular disorder: Weakness, muscular pain in limbs and neck, Shortness of breath; neuromuscular symptoms are dose-related and are mostly followed by cardiotoxicity
- Cardiac effects: Hypotension, tachycardia, and dysrhythmias; changes in electrical activity that might be followed by toxicity
- Other: Headache, nausea, vomiting, local pain
Precautions:
- Dehydroemetine should be administered only in a hospital.
- Heart rate and blood pressure of the patient should be monitored carefully, and the drug should be discontinued if there are signs of fast heartbeat, very low blood pressure or if there are any electrical changes in the heart.
- Patients with preexisting cardiac disease, renal or neuromuscular disease should strictly avoid using the drug.
- Symptoms of weakness and serious toxic effects may be warning signs to reduce dosage.
- Avoid use in pregnancy (due to its toxicity to the fetus); maybe given to protect the mother only if amebic dysentery develops in late pregnancy.
Nursing consideration
- Should be used cautiously and in reduced dosage in elderly patients
- Deep SC administration is preferred IM is acceptable but IV is contraindicated
- Pulse rate and blood pressure should be recorded. Drug use should be discontinued if its procedure tachycardia, precipitous fall in blood pressure, neuromuscular symptoms marked GI effects or considerable weakness
- Don’t exceed recommended dose or extend therapy beyond ten days bed rest should be imposed during treatment and for several days thereafter
- ECG should be taken before therapy, after fifth dose. Upon completion and I week after therapy
- Intake /output should be recorded
- To help prevent reinfestation, teach the patient the need for good personal hygiene
- Drug is very irritating, avoid contact with eyes and mucous membranes. Wear gloves and goggles when preparing injection
| Emetine |
| Availability: oral syrup 7% |
| Indication & dosage: Overdose/Poisoning 15-30 mL PO once; may repeat once with 15 mL if vomiting does not occur within 20-30 min |
| Mechanism of Action: Gastric irritant and stimulates chemoreceptor trigger zone in CNS by alkaloids emetine and cephaeline to produce vomiting |
| Metabolism & Elimination: Effective within 30 min post ingestion Absorption: Significant when emesis not produced |
| Contraindications: 1. Lethargy 2. Absent gag reflex 3. Coma 4. Short time between ingestion of poison and charcoal administration/lavage 5. History of ingestion of substance that causes CNS depression or seizures 6, Ingestion of caustics, volatile liquids, or sharp objects |
Cautions
- May not work on empty stomach
- Do not confuse ipecac syrup with ipecac fluid extract (14 times stronger)
- Not indicated if patient had spontaneous vomiting
- Falling out of favor with many poison control centers; may delay gastric lavage if vomiting prolonged
- Milk or carbonated beverages may decrease effect
- Abuse may occur in patients with bulimia or anorexia nervosa; associated with cardiomyopathies and death in patients with eating disorder
- May be cardiotoxic if not vomited and allowed to be absorbed; emetine absorption may result in heart conduction disturbances
| Iodoquinol |
| Availability: tablets 210mg,650mg |
| Indication & dosage: Intestinal Amebiasis 650 mg PO PC q8hr for 20 days; not to exceed 2 g/day |
| Mechanism of Action: Acts primarily in intestinal lumen; mechanism unknown |
| Metabolism & Elimination: Absorption: poor & erratic Metabolism: Hepatic Excretion: Primarily feces |
| Contraindications: Hypersensitivity to 8-hydroxyquinolones or iodoquinol Iodine sensitivity Pre-existing optic neuropathy Hepatic damage |
| Cautions: Caution in thyroid disease Interferes with thyroid tests for up to 6 months after discontinuation Do not repeat course before 2-3 wk. Not effective in amoebic hepatitis or liver abscess Avoid long term therapy (associated with optic neuritis and optic atrophy) |
| Metronidazole |
| Availability: Capsules: 375 mg Powder for injection: 5 mg/ml, 500-mg vials Premixed injection: 500 mg/100 ml Tablets: 250 mg, 500 mg Tablets (extended-release): 750 mg Topical cream, topical gel: 0.75% in 28.4-g tubes Topical lotion: 0.75% in 59-ml bottle Vaginal gel: 0.75% (37.5 mg/5-g applicator) in 70-g tubes |
| Indication & dosage: Trichomoniasis Adults: 2 g P.O. as a single dose or in two 1-g doses given on same day. Alternatively, 500 mg P.O. b.i.d. for 7 days. |
| 1. Bacterial infections Adults: Initially, 15 mg/kg I.V., followed by 7.5 mg/kg I.V. q 6 hours, not to exceed 4 g/day for 7 to 10 days |
| 2. Amebiasis Adults: 750 mg P.O. q 8 hours for 5 to 10 days |
| 3. Amebic liver abscess Adults: 500 to 750 mg P.O. t.i.d. for 5 to 10 days. If drug can’t be given orally, administer 500 mg I.V. q 6 hours for 10 days. Children: 35 to 50 mg/kg/day P.O. in three divided doses for 10 days, to a maximum of 750 mg/dose |
| 4. Bacterial vaginosis Adults: In nonpregnant patients, 750 mg/day P.O. (extended release) for 7 days or 5 g of 0.75% vaginal gel b.i.d. for 5 days. In pregnant patients, 250 mg P.O. t.i.d. for 7 days. |
| 5. Perioperative prophylaxis in colorectal surgery Adults: Initially, 15 mg/kg I.V. infusion over 30 to 60 minutes, completed 1 hour before surgery; if necessary, 7.5 mg/kg I.V. infusion over 30 to 60 minutes at 6 and 12 hours after initial dose |
| Rosacea Adults: Rub a thin layer of topical lotion, gel, or cream onto entire affected area morning and evening. Improvement should occur within 3 weeks. |
| Mechanism of Action: Disturbs DNA synthesis in susceptible bacterial organisms |
| Contraindications: Hypersensitivity to drug, other nitroimidazole derivatives, or parabens (topical form only) ● First-trimester pregnancy in patients with trichomoniasis |
| Precautions: ● severe hepatic impairment ● history of blood dyscrasias, seizures, or other neurologic problems ● breastfeeding patients ● children. |
| Administration : ● Reconstitute powder for injection by adding 4.4 ml of sterile or bacteriostatic water for injection, 0.9% sodium chloride injection, or bacteriostatic sodium chloride injection to 500-mg vial. Further dilute resulting concentration (100 mg/ml) in 0.9% sodium chloride injection, 5% dextrose injection, or lactated Ringer’s injection solution to a concentration of 8 mg/ml or less. Infuse each I.V. dose over 1 hour. ● Be aware that for I.V. injection, drug need not be diluted or neutralized. ● Don’t use equipment containing aluminum to reconstitute or transfer reconstituted solution to diluent; solution may turn reddish-brown. ● Don’t interchange vaginal gel with topical gel, cream, or lotion. |
| Metabolism & Elimination: Metabolism Side-chain oxidation resulting in 2 metabolites (1-(ßhydroxyethyl)-2-hydroxymethyl-5-nitroimidazole and 2-methyl-5-nitroimidazole-1-ylacetic acid) Glucuronide conjugation Elimination:Clearance: 10 hr (PO) Half-life: Capsule or tablet: 8 hr: Oral solution: 10 hr Excretion: PO or IV: 60-80% (urine); 6-15% (feces) |
Adverse reactions
CNS: dizziness, headache, ataxia, vertigo, incoordination, insomnia, fatigue
ENT: rhinitis, sinusitis, pharyngitis
GI: nausea, vomiting, diarrhea, abdominal pain, furry tongue, glossitis, dry mouth, anorexia
GU: dysuria, dark urine, incontinence
Hematologic: leukopenia
Skin: rash, urticaria, burning, mild skin dryness, skin irritation, transient redness (with topical forms)
Other: unpleasant or metallic taste, superinfection, phlebitis at I.V. site
Patient monitoring
- Monitor I.V. site. Avoid prolonged use of indwelling catheter.
- Evaluate hematologic studies, especially in patients with history of blood dyscrasias.
Patient teaching
- Advise patient to take drug with food if it causes GI upset. However, instruct him to take extended-release tablets 1 hour before or 2 hours after meals.
- Tell patient with trichomoniasis to refrain from sexual intercourse or to have male partner wear a condom to prevent reinfection. Explain that asymptomatic sex partners should be treated simultaneously.
- Advise patient to report fever, sore throat, bleeding, or bruising.
- Inform patient that drug may cause metallic taste and may discolor urine deep brownish-red.
- Tell patient using topical form to clean area thoroughly with mild cleanser before use and then wait 15 to 20 minutes before applying drug. Tell her she may apply cosmetics to skin after applying drug; with topical lotion, instruct her to let skin dry at least 5 minutes before applying cosmetics.
- Tell female patient to consult prescriber if she is pregnant or plans to become pregnant.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.
| Paromomycin |
| Availability: Capsule, 250mg |
| Indication & dosage : 1. Intestinal Amebiasis (E. Histolytica) 25-35 mg/kg/day PO divided q6hr for 5-10 days Effective in acute and chronic but not extraintestinal |
| 2. Hepatic Coma (Adjunctive) 4 g PO qDay in divided doses for 5-6 days |
| 3. Diantomoeba Fragilis 20-30 mg/kg/day PO divided q8hr |
| 4. Tapeworm (T. saginata/T. solium/D. latum/D. caninum) 11 mg/kg PO divided q15min for 4 doses |
| 5. Dwarf Tapeworm 45 mg/kg/dose PO qDay for 5-7 days Cutaneous Leishmaniasis (Orphan) Treatment of cutaneous leishmaniasis (Old World and New World) |
| Mechanism of Action: Aminoglycoside; interferes with bacterial protein synthesis by binding to 30S ribosomal subunits; has antibacterial against pathogenic organisms in the GI tract |
Metabolism & Elimination:
Absorption: Poor
Excretion: Feces (100% as unchanged drug)
Contraindications
Hypersensitivity, intestinal obstruction
Cautions
- Prescribing in absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to patient and increases risk of development of drug-resistant bacteria
- Constant observation of the patient essential; if new infections caused by nonsusceptible organisms appear during therapy, take appropriate measures
- Prolonged treatment may result in fungal or bacterial superinfection
- To avoid renal toxicity through inadvertent absorption use caution in individuals with ulcerative lesions of the bowel
- Caution in renal impairment or patients with ulcerative bowel lesions
Adverse Reactions/Side Effects
GI: abdominal cramps, diarrhea, nausea, vomiting.
Misc: hypersensitivity reactions.
Nursing consideration
Monitor signs of hypersensitivity reactions, including pulmonary symptoms (tightness in the throat and chest, wheezing, cough, dyspnea) or skin reactions (rash, pruritus, urticaria). Notify physician or nursing staff immediately if these reactions occur.
Patient/Client-Related Instructions
Patient and family/caregivers to report severe or prolonged GI problems including diarrhea, nausea, vomiting, and abdominal cramps.
| Tinidazole |
| Availability: Tablets: 250 mg, 500 mg |
| Indication & dosage : 1. Trichomoniasis caused by Trichomonas vaginalis Adults: Single dose of 2 g P.O. with food, given to both sexual partners simultaneously |
| 2. Bacterial vaginosis in nonpregnant females Adults: 2 g P.O. once daily with food for 2 days, or 1 g P.O. once daily with food for 5 days |
| 3. Giardiasis caused by Giardia duodenalis (Giardia lamblia) Adults: Single dose of 2 g P.O. with food Children older than age 3: Single dose of 50 mg/kg (up to 2 g) with food |
| 4. Amebiasis caused by Entamoeba histolytica Adults: 2 g P.O. daily with food for 3 days Children older than age 3: 50 mg/kg (up to 2 g) P.O. daily with food for 3 days |
| 5. Amebic liver abscess caused by E. histolytica Adults: 2 g P.O. daily with food for 3 to 5 days Children older than age 3: 50 mg/kg (up to 2 g) P.O. daily with food for 3 to 5 days |
| Mechanism of Action : Free nitro radical (generated from tinidazole reduction by Trichomonas cell extracts) may explain activity against Trichomonas species; activity against Giardia and Entamoeba species is unknown. |
Pharmacokinetics
- Half-life: 12-14 hr
- Metabolism: Mainly by CYP3A4
- Vd: 50L
- Protein binding: 12%
- Peak plasma time: 1.6 hr
- Metabolites: Undergoes oxidation, hydroxylation & conjugation
- Excretion: Mainly in urine (20-25% as unchanged drug); feces: 12%
Contraindications
- Hypersensitivity to drug, its components, or other nitroimidazole derivatives
- First trimester of pregnancy
Precautions:
- CNS disease, hepatic dysfunction
- history of blood dyscrasias
- elderly patients
- pregnant or breastfeeding patients
- children (except to treat giardiasis and amebiasis in children older than age 3).
Administration
Give with food to minimize GI discomfort.
Adverse reactions
CNS: weakness, fatigue, malaise, dizziness, vertigo, ataxia, insomnia, drowsiness, giddiness, headache, transient peripheral neuropathy, seizures
CV: palpitations
GI: nausea, vomiting, diarrhea, constipation, dyspepsia, gastric discomfort, tongue discoloration, stomatitis, anorexia Hematologic: transient neutropenia and leukopenia
Musculoskeletal: arthralgia, myalgia, arthritis
Other: altered taste, overgrowth of susceptible organisms, hypersensitivity reactions including angioedema
Patient monitoring
- Closely monitor patient for neurologic abnormalities, such as seizures and peripheral neuropathy. If these occur, withdraw drug immediately
- Monitor blood chemistry tests, especially liver function tests.
Patient teaching
- Advise patient to take drug with food.
- For child or other patient unable to swallow tablets, inform parent or caregiver that drug can be crushed in artificial cherry syrup and given with food.
- Caution patient or caregiver to stop therapy and call prescriber immediately if seizures or numbness or tingling in extremities occurs.
- Instruct patient to avoid alcohol use during therapy.
- Advise female patient to avoid pregnancy during therapy.
- Counsel female patient to avoid breastfeeding during therapy and for 3 days after last dose.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and behaviors mentioned above.
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
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