S.Sparlin and C.SullivanSulfonamides

Sulfonamides

·         History

-one of the oldest antibacterial agents used to combat infection

-isolated from a coal tar derivative in the early 1900’s

-produced for clinical use against coccal infections in 1935

-first group of drugs used against bacteria (Bacteriostatic-inhibit bacterial synthesis of folic acid, which is essential for bacterial growth)

-not classified as an antibiotic because they are not obtained from biological substances

·         Uses

-Usefulness of sulfonamides alone, not in combination (such as trimethoprim-sulfamethozxazole) has decreased for several reasons

1.      Availability and effectiveness of penicillin and other antibiotics has increased

2.      Bacterial resistance to some sulfonamides can develop

-used as an alternative for clients allergic to PCN

-used to treat UTI’s, ear infections, newborn eye prophylaxis, meningococcal meningitis, chlamydia and toxoplasma gondii.

-not effective  against viruses and fungi.

·         Pharmacokinetics

-well absorbed by the GI tract

-well distributed to body tissues and brain

-metabolized by the liver

-excreted by the kidney

·         Pharmacodynamics

-many for oral administration as they are readily absorbed by GI tract

-available in solution and ointment for ophthalmic use

-available in creams for burns

-Two categories of sulfonamides based on duration of action

1.      Short-acting sulfonamides have a rapid action and excretion rate.  (sulfadiazine)

2.      Intermediate-acting sulfonamides have moderate to slow absorption and slow excretion rate (sulfasalazine and trimethoprim-sulfamethoxazole)

 

·         Side effects/Adverse Reactions

-allergic response  such as rash/itching(Anaphylaxis is not common)

-blood disorders with prolonged use in high doses

-GI disturbances

-crystalluria (crystals in the urine) and hematuria with early sulfonamides

-photosensitivity

-cross-sensitivity (a sensitivity or allergy to one sulfonamide may lead to sensitivity of other sulfonamides

- avoid during third trimester of pregnancy

·         Nursing process

1.      Assessment

·         Assess client’s renal function by checking urinary output, BUN, and creatinine. Check CBC as baseline laboratory results.

·         Obtain client’s medical history. Co-trimoxazole is contraindicated in patients with severe liver or severe renal disease.

·         Determine if client has allergy to sulfonamides.

·         Obtain client’s drug history. Antidiabetic medications with sulfonamides can increase the risk of hypoglycemia. Warfarin with sulfonamides can increase anticoagulation effect.

2.      Diagnoses

·         Ineffective protection as evidenced by photosensitivity r/t sulfonamides

·         Impaired urinary elimination r/t prolonged high doses of sulfanomides

3.      Planning

·         Client’s infection will be controlled and later alleviated.

4.      Interventions

·         Monitor clients I/O. Adult intake should be 2000ml/d and output should be 1200ml/d.

·         Monitor clients VS. Closely monitor temperature for decrease.

·         Monitor client for hematologic reaction, which can be life threatening. S/Sx include sore throat, purpura, decreasing WBC and platelet counts. Check CBC to compare to baseline CBC results.

·         Monitor for s/sx of superinfection. S/sx include stomatitis, furry black tongue, anal or genital discharge, and itching.

5.      Teaching

·         Instruct client to drink several quarts of fluids daily to avoid crystalluria due to taking sulfonamides.

·         Inform clients not to take antacids while on sulfonamides due to decrease absorption.

·         Inform clients with allergies to sulfonamides to avoid all sulfonamide preparations.

·         Inform pregnant clients not to take sulfonamides the last three months of pregnancy.

·         Prototype for sulfamethoxazole/trimethroprin

1.      Class

·         Antibacterial

2.      Contraindications

·         Severe renal or hepatic disease, hypersensitivity to sulfonamides

3.      Drug/lab/food interactions

·         Drug: Warfarin increases anticoagulation effects; Antidiabetic increases hypoglycemic effect.

·         Lab: BUN, creatinine, AST, ALT, ALP may be increased.

4.      Pharmacodynamics

PO: Onset-30mins-1hr

Duration: unknown

IV: onset immediate

Peak: 30mins-1hr

Duration: unknown

5.      Pharmacokinetics

·         Absorption: PO-Well absorbed

·         Distribution: PB-50%-65%, crosses placenta

·         Metabolism: t^1/2: 8-12h

·         Excretion: In urine as metabolites

6.      Therapeutic effects/uses

·         To treat UTI’s, otitis media, bronchitis, PNA, rheumatic fever, burns, and pneumatic carinii infection.

·         Mode of action: Inhibition of protein synthesis of nucleic acids; bactericidal effect.

7.      Side effects

·         Nausea, vomiting, diarrhea, rash, stomatitis, fatigue, depression, headache, vertigo, photosensitivity, anorexia.

8.      Adverse effects

·         Life-threatening: Leukopenia, thrombocytopenia, increased bone marrow depression, hemolytic anemia, aplastic anemia, agranulocytosis, Stevens-Johnson syndrome, renal failure.

·         Interesting fact

Currently shortage on several different sulfa combinations

Refer to www.ashp.org/menu/DrugShortages or www.fda.gov/Drugs/DrugSafety/DrugShortages/ucm314743.htm#sulfamethoxazole

·         Questions

 

References

Kee, J. L., Hayes, E. R., & McCuistion, L. E. (2012). Pharmacology. A nursing process approach. St. Louis, MO: Elsevier.