Tindamax


tinidazole

Fasigyn, Tindamax

Pharmacologic class: Antiprotozoal

Therapeutic class: Anti-infective

Pregnancy risk category C

FDA Box Warning

Prolonged use of metronidazole (a structurally related drug with similar biologic effects) has caused cancer in mice and rats. Reserve tinidazole for conditions listed under "Indications and dosages."

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.

Availability

Tablets: 250 mg, 500 mg

Indications and dosages

Trichomoniasis caused by Trichomonas vaginalis

Adults: Single dose of 2 g P.O. with food, given to both sexual partners simultaneously

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

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

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

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

Dosage adjustment

• Hemodialysis patients

Contraindications

• Hypersensitivity to drug, its components, or other nitroimidazole derivatives

• First trimester of pregnancy

Precautions

Use cautiously in:

• 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

Interactions

Drug-drug. Cyclosporine, lithium, tacrolimus: possible increase in blood levels of these drugs

Cholestyramine: decreased oral bioavailability of tinidazole

CYP450 inducers (such as phenobarbital, rifampin): increased tinidazole elimination and decreased blood level

CYP450 inhibitors (such as cimetidine, ketoconazole): increased tinidazole blood level

Fluorouracil: decreased fluorouracil clearance

Fosphenytoin, phenytoin: prolonged half-life and reduced clearance of these drugs

Oxytetracycline: antagonism of therapeutic effects of tinidazole

Warfarin, other oral coumarin anticoagulants: increased effects of these drugs

Drug-diagnostic tests. Alanine aminotransferase, aspartate aminotransferase, hexokinase glucose, lactate dehydrogenase, triglycerides: interference with test results

Drug-behaviors. Alcohol use: disulfiram-like reaction during tinidazole therapy and for 3 days after

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.

tinidazole

(ti-nid-a-zole) tinidazole,

Tindamax

(trade name)

Classification

Therapeutic: antiprotozoals
Pharmacologic: imidazoles
Pregnancy Category: C

Indications

Bacterial vaginosis.Trichomoniasis.Giardiasis.Amebiasis.

Action

Interaction with protozoa results in release of a free nitro radical that has antiprotozoal activity.

Therapeutic effects

Resolution of protozoal infections.Active against Trichamonas vaginalis, Giardia duodenalis (also known as Giardia lamblia), and Entamoeba histolytica.

Pharmacokinetics

Absorption: Rapidly and completely absorbed following oral administration.Distribution: Extensively distributed; crosses placenta and blood-brain barrier, enters breast milk.Metabolism and Excretion: Mostly metabolized (CYP3A4 enzyme system); 20–25% excreted unchanged in urine, 12% excreted in feces.Half-life: 12–14 hr.

Time/action profile (blood levels)

ROUTEONSETPEAKDURATION
POrapid2 hr24 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity; cross sensitivity with other imidazoles may occur; Obstetric: First trimester of pregnancy; Lactation: Lactation.Use Cautiously in: CNS pathology; History of blood dyscrasia; Hemodialysis (removes significant amount of tinidazole; supplement post-dialysis with additional 50% of dose); Hepatic impairment; Unrecognized candidiasis (requires concurrent antifungal therapy); Pediatric: Children <3 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

  • dizziness
  • headache
  • malaise

Gastrointestinal

  • constipation
  • dyspepsia
  • metallic/bitter taste
  • vomiting

Hematologic

  • transient leukopenia/neutropenia

Interactions

Drug-Drug interaction

↑ risk of bleeding with warfarin.Disulfiram-like reaction may occur with alcohol or propylene glycol ; disulfiram should be avoided for at least 2 weeks before tinidazole.May ↑ levels of lithium, cyclosporine, tacrolimus, fluorouracil, and fosphenytoin (observe/monitor for toxicity if administered concurrently).Drugs that induce the CYP450 liver enzyme system (phenobarbital, rifampin, phenytoin or fosphenytoin ) may ↓ levels and effectiveness.Drugs that inhibit the CYP450 liver enzyme system (cimetidine or ketoconazole ) may ↑ levels.Absorption is ↓ by cholestyramine ; separate dosing.

Route/Dosage

Oral (Adults) Bacterial vaginosis—1 g once daily for 5 days or 2 g once daily for 2 days; Trichomoniasis and Giardiasis—2 g single dose; Intestinal amebiasis—2 g once daily for 3 days; Amebic liver abscess—2 g once daily for 3–5 days.Oral (Children >3 yr) Giardiasis—50 mg/kg (up to 2 g) single dose; Intestinal amebiasis—50 mg/kg once daily for 3 days; Amebic liver abscess—50 mg/kg once daily for 3–5 days.

Availability (generic available)

Tablets: 250 mg, 500 mg

Nursing implications

Nursing assessment

  • Assess patient for symptoms of infection (discharge, itching) prior to and during therapy.
  • Monitor neurologic status during and after IV infusions. Inform health care professional if numbness, paresthesia, weakness, ataxia, or convulsions occur.
  • Giardiasis: Monitor three stool samples taken several days apart, beginning 3–4 wk after treatment.
  • Lab Test Considerations: May cause transient leukopenia and neutropenia. Monitor total and differential leukocyte counts if retreatment is necessary.
    • May interfere with certain tests of serum chemistry values such as AST, ALT, LDH, triglycerides, and glucose hexokinase.

Potential Nursing Diagnoses

Risk for infection (Indications)
Diarrhea (Indications)

Implementation

  • Symptoms of known or previously unrecognized candidiasis may become worse during therapy and require treatment with an antifungal agent.
  • Oral: Administer with food to decrease GI upset. May be crushed and prepared as a suspension in cherry syrup by pharmacist for patients unable to swallow tablets. Shake well before administering.

Patient/Family Teaching

  • Instruct patient to take medication as directed, even if feeling better. Do not skip doses or double up on missed doses. If a dose is missed, take as soon as remembered if not almost time for next dose.
  • Advise patients treated for trichomoniasis that sexual partners may be asymptomatic sources of reinfection and should be treated concurrently. Patient should also refrain from intercourse or use a condom to prevent reinfection.
  • Caution patient to avoid intake of alcoholic beverages or preparations containing alcohol during and for at least 3 days after treatment with tinidazole. May cause a disulfiram-like reaction (flushing, nausea, vomiting, headache, abdominal cramps).
  • May cause dizziness or drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Inform patient that medication may cause an unpleasant metallic taste.
  • Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
  • Advise patient to inform health care professional if pregnancy is suspected or if breastfeeding before taking this medication.

Evaluation/Desired Outcomes

  • Resolution of signs and symptoms of infection.