Giardiasis is an infection in your small intestine. It’s caused by a microscopic parasite called Giardia lamblia. Giardiasis spreads through contact with infected people
Giardiasis
- Metronidazole
- Nitazoxanide
- Tinidazole
| Metronidazole |
| Availability:capsule 375mg Tablet 250mg,500mg tablet, extended-release,750mg oral suspension,500mg/5mL (Likmez) infusion solution,500mg/100mL |
| Indication & dosage To treat amebiasis (Entamoeba histolytica) CAPSULES,TABLETS Adults. 500 to 750 mg t.i.d. for 5 to 10 days. Children. 11.6 to 16.7 mg/kg t.i.d. for 10 days. |
| To treat trichomoniasis (Trichomonas vaginalis) CAPSULES,TABLETS Adults. 2,000 mg as a single dose, 1,000 mg b.i.d. for 24 hr, or 250 mg t.i.d. for 7 days. Children. 5 mg/kg t.i.d. for 7 days. |
| To prevent perioperative bowel infection I.V. INFUSION Adults and adolescents. 15 mg/kg 1 hr before surgery and then 7.5 mg/kg 6 and 12 hr after initial dose. |
| To treat acne in patients with rosacea TOPICAL GEL Adults. Thin film applied to affected area b.i.d. for 9 wk. |
| To treat bacterial vaginosis VAGINAL CREAM Adults. 500 mg (1 applicatorful) once or twice daily for 10 to 20 days. VAGINAL GEL Adults. 37.5 mg (1 applicatorful) once or twice daily for 5 days. VAGINAL TABLETS Adults. 500 mg at bedtime for 10 to 20 days. |
| To treat systemic anaerobic infections caused by Bacteroides fragilis, Clostridium difficile, Clostridium perfringens, Eubacterium, Fusobacterium, Peptococcus, Peptostreptococcus, and Veillonella species 1. CAPSULES,TABLETS Adults and adolescents. 7.5 mg/kg up to 1,000 mg every 6 hr for 7 days or longer. Maximum: 4,000 mg daily. Children. 7.5 mg/kg every 6 hr or 10 mg/kg every 8 hr. 2. I.V. INFUSION Adults and adolescents. Initial: 15 mg/kg and then 7.5 mg/kg up to 1,000 mg every 6 hr for 7 days or longer. Maximum: 4,000 mg daily. Children. 7.5 mg/kg every 6 hr or 10 mg/kg every 8 hr |
| Mechanism of Action : Undergoes intracellular chemical reduction during anaerobic metabolism. After metronidazole is reduced, it damages DNA’s helical structure and breaks its strands, which inhibits bacterial nucleic acid synthesis and causes cell death. |
| Contraindications : Breast-feeding, hypersensitivity to metronidazole or its components, trichomoniasis during first trimester of pregnancy |
| Administration : IV Administration Infusion only Avoid contact between drug and aluminum in infusion set (less critical for RTU infusion solution containing metronidazole rather than metronidazole HCl) Oral Administration Oral solution •Shake the bottle well before administering •Use a calibrated oral dosing device to correctly measure the prescribed dose of medication; do not use household teaspoons or tablespoons to measure doses. •Calibrated oral dosing devices may be obtained from the pharmacy |
| 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: Aseptic meningitis (parenteral form), ataxia, confusion, dizziness, encephalopathy, fever, headache, incoordination, insomnia, irritability, light-headedness, peripheral neuropathy, seizures (high doses), syncope, weakness, vertigo
ENT: Dry mouth, lacrimation (topical form), metallic taste, nasal congestion, optic neuropathy, pharyngitis
GI: Abdominal cramps or pain, anorexia, diarrhea, nausea, pancreatitis, vomiting
GU: Dark urine, vaginal candidiasis (oral, parenteral, and topical forms); burning or irritation of sexual partner’s penis, candidal cervicitis or vaginitis, dysuria, dryness of vagina or vulva, urinary frequency, vulvitis (vaginal form)
HEME: Leukopenia
MS: Back pain, dysarthria
SKIN: Burning or stinging sensation, dry skin (topical form); erythema, flushing, pruritus, rash, Stevens Johnson syndrome, urticaria (oral and parenteral forms)
Other: Injection site edema, pain, or tenderness
Nursing Considerations
- Give I.V. drug by slow infusion over 1 hour; don’t give by direct I.V. injection.
- Discontinue primary I.V. infusion during metronidazole infusion.
- Monitor patient with severe liver disease because slowed metronidazole metabolism may cause drug to accumulate in body and increase the risk of adverse effects.
- If skin irritation occurs, apply topical metronidazole gel less frequently or discontinue it, as ordered.
- Monitor CBC and culture and sensitivity tests if therapy lasts longer than 10 days or if second course of treatment is needed.
PATIENT TEACHING
- Instruct female patient to notify prescriber if she is pregnant, intends to get pregnant, or is breast-feeding.
- Urge patient to take metronidazole at evenly spaced intervals day and with food to minimize adverse GI reactions.
- Urge patient to complete the entire course of therapy.
- Caution patient to avoid alcohol during therapy and for at least 3 days afterward.
- Advise patient to avoid hazardous activities until drug’s CNS effects are known and to report any abnormal neurologic signs or symptoms, such as weakness, numbness, seizures, or vision changes.
- If patient reports dry mouth, suggest ice chips or sugarless hard candy or gum; suggest a dental visit if dryness lasts longer than 2 weeks.
- Instruct patient to notify prescriber if no improvement occurs within a few days of taking tablets or capsules.
- Direct patient using topical gel to wash hands and affected area with a mild, nonirritating cleaner; to rinse well and pat dry; and then to apply a thin film of drug and wash hands again.
- Advise patient with rosacea to keep topical gel away from his eyes. If drug gets into his eyes, urge him to wash them immediately with large amounts of cool tap water and to call prescriber if eyes continue to hurt or burn.
- Instruct patient with rosacea to notify prescriber if no improvement occurs after 3 weeks of topical use; full therapeutic effect may take 9 weeks.
- Teach patient how to fill, insert, and clean vaginal cream or gel applicator after use. Instruct her to wash her hands before and after administration.
- To help vaginal tablets dissolve, instruct patient to run tap water over unwrapped tablet for a few seconds before insertion.
- Inform patient with trichomoniasis that her male sexual partners should wear condoms during her treatment and that they may need treatment themselves to prevent reinfection.
- Caution patient that vaginal cream and tablets (not gel) may contain oils that damage latex condoms.
- Urge patient to follow up with patient
| Nitazoxanide |
| Availability: Oral suspension: 100 mg/5 ml Tablets: 500 mg |
| Indication & dosage : ØDiarrhea caused by Giardia lamblia or Cryptosporidium parvum Adults and children ages 12 and older: 500 mg (tablet or 25 ml suspension) P.O. every 12 hours with food for 3 days Children ages 4 to 11: 200 mg (10 ml suspension) P.O. every 12 hours with food for 3 days Children ages 1 to 3: 100 mg (5 ml suspension) P.O. every 12 hours with food for 3 days |
| Mechanism of Action : May destroy Cryptosporidium parvum and Giardia lamblia by interfering with enzymedependent electron transfer required for their anaerobic energy metabolism. Other unidentified mechanisms may also be involved. With loss of protozoal activity in the intestines, diarrhea ceases. |
| Contraindications : Hypersensitivity to drug or its components |
| Administration: ● Give with food. ● Because a single tablet contains more nitazoxanide than recommended for pediatric dosing, don’t give tablets to children younger than age 11. ● Keep suspension container tightly closed and shake well before each use. Suspension may be stored for 7 days; after that, discard unused portion. |
| Metabolism & Elimination: Metabolism: hydrolysis & glucuronidation Metabolites: Tizoxanide, tizoxanide glucuronide (100% conversion) Excretion: Urine, bile, feces Peak PlasmaTime: 1-4 hr Peak plasma concentration: 3 mcg/mL AUC: 12-19 mcg.hr/mL |
Precautions:
- renal, hepatic, or biliary disease or dysfunction; immunodeficiency (including human immunodeficiency virus); diabetes mellitus (suspension)
- concurrent use of warfarin or other highly plasma protein–bound drugs
- elderly patients
- pregnant or breastfeeding patients
- children younger than age 11 (tablets) or age 1 (suspension).
Adverse reactions
CNS: headache
GI: nausea, vomiting, diarrhea, abdominal pain
Patient monitoring
- Monitor renal and liver function tests frequently in patients with renal, hepatic, or biliary dysfunction.
- Monitor blood glucose levels in diabetic patients taking oral suspension.
Patient teaching
- Instruct patient to take drug with food
- Inform diabetic patient that oral suspension contains sucrose.
- As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs mentioned above.
Nursing Considerations
- Use nitazoxanide cautiously in children with impaired hepatic function, biliary disease, or renal insufficiency.
- Prepare suspension by first tapping bottle until powder flows freely. Add 24 ml of tap water to powder and shake vigorously to suspend powder. Add another 24 ml water and shake vigorously again. Keep bottle of reconstituted suspension tightly capped.
- Use oral suspension for children age 11 and under because tablets contain more nitazoxanide than is recommended for children under age 12.
| 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 : Undergoes intracellular chemical reduction during anaerobic metabolism. After tinidazole is reduced, it damages DNA’s helical structure and breaks its strands, which inhibits bacterial nucleic acid synthesis and causes cell death. |
Contraindications
Breast-feeding, hypersensitivity to tinidazole or its components, treatment of trichomoniasis during 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, diarrhoea, 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.
Nursing Considerations
- Use tinidazole cautiously in patients with CNS disease or blood dyscrasias because tinidazole’s adverse effects may worsen these disorders. Also use cautiously in patients with hepatic impairment because a chemically related drug has reduced elimination.
- Take seizure precautions. If a seizure or other abnormal neurologic symptoms occur, notify prescriber and expect to stop drug.
- Treat a patient diagnosed with trichomoniasis and her sexual partner with the same dose of tinidazole and at the same time, as ordered, because trichomoniasis is a sexually transmitted disease.
- Monitor patient’s total WBC count and differential if retreatment with tinidazole is needed because adverse hematologic reactions may occur with repeated use.
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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