Name of the Acidifiers Drugs
- Nitrofurantoin
- Methenamine
- Tetracyclines
1.Nitrofurantoin
| Nitrofurantoin |
| Availability Capsules: 25 mg, 50 mg, 100 mg (macrocrystals) Capsules (extended release): 100 mg (macrocrystals) Oral suspension: 25 mg/5 ml Tablets: 50 mg, 100 mg (macrocrystals) |
| Indications and dosages ➣ Active urinary tract infections (UTIs) Adults: 50 to 100 mg P.O. q.i.d. or 100 mg q 12 hours (extended-release), continued for 1 week, or for 3 days after urine becomes sterile Children older than 1 month: 5 to 7 mg/kg/day P.O. in four divided doses, continued for 1 week, or for 3 days after urine becomes sterile ➣ Chronic suppression of UTIs Adults: 50 to 100 mg P.O. at bedtime Children: 1 mg/kg/day P.O. in one or two divided doses |
Mechanism of Action
Inactivates or alters bacterial ribosomal proteins and other macromolecules. This action of nitrofurantoin inhibits bacterial protein synthesis, aerobic energy metabolism, DNA synthesis, RNA synthesis, and cell wall synthesis. Nitrofurantoin is bacteriostatic at low doses and bactericidal at higher doses.
Pharmacokinetics
- Bioavailability: Increased with food
- Protein bound: Approximately 60-90%
- Reduced by bacterial flavoproteins to reactive intermediates
- Half-life: 20-60 min; prolonged with renal impairment
- Excretion: Urine (40%); feces (small amounts)
Administration
- As appropriate, obtain specimens for repeat urine culture and sensitivity tests before therapy.
- To avoid GI upset and increase drug bioavailability, give with food or milk.
Contraindications
- Hypersensitivity to drug or parabens (oral suspension)
- Oliguria, anuria, or significant renal impairment
- Pregnancy near term (38 to 42 weeks’ gestation), imminent labor onset, labor and delivery
- Infants younger than 1 month
Precautions:
- Diabetes mellitus, renal impairment
- Blacks and patients of Mediterranean or near-Eastern descent (because of possible G6PD deficiency)
- Elderly or debilitated patients
- Pregnant (to week 32) or breastfeeding patients.
Adverse reactions
- CNS: dizziness, drowsiness, headache, asthenia, peripheral neuropathy, vertigo
- CV: chest pain
- EENT: nystagmus
- GI: nausea, vomiting, diarrhea, abdominal pain, anorexia, parotitis, pancreatitis
- Hematologic: eosinophilia, agranulocytosis, thrombocytopenia, leukopenia, granulocytopenia, G6PD deficiency anemia, hemolytic anemia, megaloblastic anemia
- Hepatic: hepatitis, hepatic necrosis
- Musculoskeletal: arthralgia, myalgia
- Respiratory: asthma attacks, pulmonary hypersensitivity reactions including diffuse interstitial pneumonitis (with prolonged therapy)
- Skin: rash, exfoliative dermatitis, alopecia, pruritus, urticaria, angioedema, photosensitivity, Stevens-Johnson syndrome Other: drug fever, chills, superinfection (limited to urinary tract), hypersensitivity reactions including anaphylaxis, lupus-like syndrome
Patient monitoring
- Monitor patient’s response to therapy. Assess urine culture and sensitivity tests.
- Watch for and immediately report peripheral neuropathy.
- Assess respiratory status. Watch for signs and symptoms of serious pulmonary hypersensitivity reaction.
- Monitor CBC and liver function tests closely. Stay alert for evidence of hematologic and hepatic disorders.
- Evaluate patient for rash.
Patient teaching
- Instruct patient to take with food or milk at regular intervals around the clock.
- Advise patient to complete entire course of therapy.
- Tell patient not to take magnesiumcontaining drugs (such as antacids) during therapy.
- Caution patient not to drive or perform other hazardous activities until he knows how drug affects vision, concentration, and alertness.
- Tell patient to immediately report fever, chills, cough, chest pain, difficulty breathing, rash, bleeding or easy bruising, dark urine, yellowing of skin or eyes, numbness or tingling of fingers or toes, or intolerable GI distress.
- Advise female patient to avoid taking drug during pregnancy, especially near term.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.
Nursing Considerations
- Obtain a specimen of patient’s urine for culture and sensitivity tests, as ordered; review test results if possible before giving nitrofurantoin.
- Give drug with food or milk to avoid staining teeth.
- Don’t crush or break capsules.
- Shake oral nitrofurantoin suspension before pouring dose, and mix with food or milk, as needed.
- Monitor patient for evidence of superinfection, such as abdominal pain, diarrhea, and fever. If patient develops diarrhea, it may indicate pseudomembranous colitis caused by Clostridium difficile. Notify prescriber and expect to withhold nitrofurantoin and treat with fluids, electrolytes, protein, and an antibiotic effective against C. difficile.
- Monitor patient for pulmonary and hepatic abnormalities because rare but severe reactions have occurred with nitrofurantoin use, especially in the elderly.
- Observe patient for changes in nervous function because peripheral neuropathy, although uncommon, may become severe or irreversible. Patients with renal impairment, anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency, or debilitating disease are at higher risk for peripheral neuropathy
2.Methenamine
| Methenamine |
| Availability tablet, hippurate1g tablet, mandelate 500mg,1g |
| Indications and Dosages To prevent or suppress frequently recurring UTI caused by a wide variety of gram-negative and gram-positive bacteria (including enterococci, Escherichia coli, Micrococcus pyogenes, and staphylococci) in intermittently catheterized patients with neurogenic bladder ENTERIC-COATED TABLETS, ORAL SUSPENSION (METHENAMINE MANDELATE) Adults and adolescents. 1 g q.i.d. before meals and at bedtime. Children ages 6 to 12. 500 mg q.i.d., or 50 mg/kg daily in divided doses. Children under age 6. 18.4 mg/kg q.i.d. TABLETS (METHENAMINE HIPPURATE) Adults and adolescents. 1 g b.i.d. Children ages 6 to 12. 0.5 to 1 g every 12 hr. |
Mechanism of Action
Hydrolyzes to formaldehyde and ammonia in an acidic environment, such as urine, producing greater amounts of formaldehyde as pH decreases. Formaldehyde has bactericidal action, possibly by denaturing proteins. To facilitate hydrolysis, methenamine is formulated with weak organic acid, such as hippuric acid or mandelic acid.
Pharmacokinetics
- Half-life: 4.3 hr
- Onset: 30 min
- Peak plasma time: 3-8 hr
- Vd: 0.56 L/kg
- Excretion: urine; methenamine 90% excreted w/in 24 hr; mandelic or hippuric acid may accumulate with severe renal impairment
Contraindications
Concurrent therapy with sulfonamides, hypersensitivity to methenamine, renal insufficiency, severe dehydration, severe hepatic disease
Adverse Reactions
- CNS: Headache
- CV: Edema EENT: Stomatitis
- GI: Abdominal cramps, anorexia, diarrhoea, nausea, vomiting
- GU: Bladder irritation, crystalluria, dysuria,hematuria, proteinuria, urinary frequency
- RESP: Pulmonary hypersensitivity (dyspnoea, pneumonitis)
- SKIN: Pruritus, rash, urticaria
Nursing Considerations
- Be aware that methenamine is used for prophylaxis; it isn’t recommended as primary treatment for UTI.
- Drug shouldn’t be given to patients with creatinine clearance less than 50 ml/min/ 1.73 m2.
- Before giving first dose, expect to obtain urine specimen for culture and sensitivity tests and to review test results if available.
- Plan to give methenamine mandelate around the clock to maintain a therapeutic blood level.
- Make sure patient receives adequate fluids.
- Expect to repeat culture and sensitivity tests if patient fails to improve.
Patient Teaching
- Instruct patient to take methenamine with food to avoid GI distress.
- Direct patient to drink extra fluids; avoid alkaline foods, such as milk, milk products, and most fruits; and avoid antacids that contain sodium bicarbonate or carbonate during methenamine therapy.
- Instruct patient to report painful urination, rash, or severe GI distress.
- Urge patient to comply with urine testing before and during long-term therapy
3.Tetracyclines
| Tetracyclines |
| Availability Capsules: 250 mg, 500 mg |
| Indications and dosages ➣ Mild to moderate infections caused by susceptible organisms Adults: 500 mg P.O. b.i.d. or 250 mg P.O. q.i.d. ➣ Severe infections caused by susceptible organisms Adults: 500 mg P.O. q.i.d. Children older than age 8: 25 to 50 mg/kg P.O. q.i.d ➣ Syphilis in penicillin-allergic patients Adults: 500 mg P.O. q.i.d. for 14 days ➣ Late syphilis (except neurosyphilis) Adults: 500 mg P.O. q.i.d. for 28 days ➣ Leptospirosis when penicillin is contraindicated or ineffective Adults: 1 to 2 g P.O. daily in two to four divided doses for 5 to 7 days ➣ Yaws Adults: 1 to 2 g P.O. daily in two to four divided doses for 10 to 14 days ➣ Gonorrhea in penicillin-allergic patients Adults: Initially, 1.5 g P.O., followed by 500 mg P.O. q 6 hours for 4 days, up to a total of 9 g ➣ Uncomplicated urethral, endocervical, or rectal infections caused by Chlamydia trachomatis Adults: 500 mg P.O. q.i.d. for 7 days ➣ Rickettsial and mycoplasmal infections Adults: 1 to 2 g P.O. daily in two to four divided doses for 7 days ➣ Helicobacter pylori infection Adults: In patients with active duodenal ulcer, 500 mg P.O. q.i.d. at meals and bedtime for 14 days, given with other drugs (such as metronidazole, bismuth subsalicylate, amoxicillin, or omeprazole) ➣ Brucellosis Adults: 500 mg P.O. q.i.d. for 3 weeks, given with streptomycin I.M. b.i.d. during week 1 and streptomycin once daily during week 2 ➣ Granuloma inguinale; chancroid Adults: 1 to 2 g P.O. daily in two to four divided doses for 2 to 4 weeks ➣ Cholera Adults: 500 mg P.O. q 6 hours for 48 to 72 hours ➣ Plague when streptomycin is contraindicated or ineffective Adults: 2 to 4 g P.O. q.i.d. for 10 days Children older than age 8: 30 to 40 mg/kg P.O. q.i.d. for 10 to 14 days ➣ Tularemia as an alternative to streptomycin Adults: 1 to 2 g P.O. daily in two to four divided doses for 1 to 2 weeks ➣ Campylobacter infection Adults: 1 to 2 g P.O. daily in two to four divided doses for 10 days ➣ Relapsing fever caused by Borrelia recurrentis Adults: 1 to 2 g P.O. daily in two to four divided doses for 7 days or until patient is afebrile ➣ Adjunctive treatment of inflammatory acne Adults and adolescents: 500 mg to 1 g P.O. q.i.d. for 1 to 2 weeks, decreased gradually to 125 to 500 mg P.O. daily |
Mechanism of Action
Exerts a bacteriostatic effect against a wide variety of gram-positive and gram-negative organisms by passing through the bacterial lipid bilayer, where it binds reversibly to 30S ribosomal subunits. Bound tetracycline blocks the binding of aminoacyl transfer RNA to messenger RNA, thus inhibiting bacterial protein synthesis.
Administration
- Give with 8 oz of water at least 1 hour before or 2 hours after a meal (especially if it includes milk or other dairy products), antacids, laxatives, or antidiarrheal drugs.
Contraindications
- Hypersensitivity to drug, other tetracyclines, bisulfites, or alcohol (in some products)
Precautions:
- Renal disease, hepatic impairment, nephrogenic diabetes insipidus
- Cachectic or debilitated patients
- Pregnant or breastfeeding patients (except in anthrax treatment)
- Children younger than age 8 (except in anthrax treatment).
Adverse reactions
- CNS: paresthesia, benign intracranial hypertension
- CV: pericarditis
- EENT: abnormal conjunctival pigmentation, hoarseness, pharyngitis
- GI: nausea, vomiting, diarrhea, loose bulky stools, esophageal ulcers, epigastric distress, enterocolitis, oral and anogenital candidiasis, stomatitis, black hairy tongue, glossitis, anorexia, pancreatitis
- GU: dark yellow or brown urine, vaginal candidiasis, anogenital lesions
- Hematologic: eosinophilia, hemolytic anemia, neutropenia, thrombocytopenia, thrombocytopenia purpura
- Hepatic: fatty liver
- Musculoskeletal: retarded bone growth, polyarthralgia
- Respiratory: pulmonary infiltrates
- Skin: photosensitivity, maculopapular or erythematous rash, increased pigmentation, urticaria, onycholysis
- Other: permanent tooth discoloration (in children younger than age 8), tooth enamel defects, superinfection, hypersensitivity reactions including anaphylaxis, serum sickness–like reaction, exacerbation of systemic lupus erythematosus
Patient monitoring
- Monitor for signs and symptoms of superinfection and hypersensitivity reaction.
- With long-term use, monitor CBC, liver function tests, and (in prepubertal patients) bone growth.
- Assess neurologic status. Stay alert for benign intracranial hypertension (especially in children).
Patient teaching
- Tell patient to take oral form with 8 oz of water at least 1 hour before or 2 hours after eating a meal, consuming dairy products, or taking antacids, laxatives, or antidiarrheal drugs. Advise him to take last daily dose at least 1 hour before bedtime.
- Stress importance of completing entire course of therapy as ordered, even after symptoms improve.
- Caution patient not to use outdated tetracycline, because it may cause serious kidney disease.
- Teach patient to recognize and report signs and symptoms of yeast infection and other infections.
- With long-term therapy, tell patient he’ll undergo regular blood testing. Advise parents that prepubertal child should have periodic bone X-rays.
- Caution patient to avoid alcohol during therapy.
- Tell parents that tetracycline use during tooth development period (last half of pregnancy, infancy, and childhood to age 8) may cause permanent yellow, gray, or brownish tooth discoloration.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, 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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