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Antibiotics & Pregnancy
By Anas Hindawi
RHUH intern
Antibiotics categories Prophylactic Abx Case presentation and Tx Abx Common infections Tx
Extra common presentation case
PPT summary
FDA Drug Categories
Antibiotic Category Antibiotic Category
Ampicillin B Tetracyclines D
Amoxycillin B Quinolones D
Cephalosporines B Azithromycin B
Clarithromycin C
Clindamycin B Aminoglycosides
Amikacin C
Gentamycin C
Strepto./Kana C
Antibiotics In Pregnancy
Drugs in Pregnancy
FIRST TRIMESTER :
congenital malformations (teratogenesis)
SECOND & THIRD TRIMESTER :
affect growth & fetal development or
toxic effects on fetal tissues
NEAR TERM :
adverse effects on Labour or
neonate after delivery
MethotrexateACE inhibitorsCarbamazepine (Tegretol)Valproic acid (Depakote)Isotretinoin (Accutane)WarfarinNSAIDs (Ibuprofen, Indomethacin)
Do Not Prescribe!
condition 1st choice prophy.
2nd choice prophy.
comments
Endocarditis Amoxicillin Clindamycin As per BritishSociety ofAntimicrobialChemotherapyguidelines [8]
Meningococcalmeningitis
Rifampicin Ceftriaxoneintramuscularly
Surgical prophylaxis
Clean surgery No prophylaxis As per Scottish
Clean-contaminatedsurgery
Cefuroxime –single dose
IntercollegiateGuidelinesNetworkrecommendations[9]
Contaminated surgery
Cefuroxime andmetronidazole –one to threedoses
Tuberculosis Isoniazid Give pyridoxinesupplements withisoniazid
Antibiotics throughout pregnancy
22 yo G1P0 with h/o frequent UTIs has a positive urine culture at her 1st OB visit. After treating this, you repeat a culture at 12 weeks which is negative. She is seen on L&D with a symptomatic UTI at 24 weeks and admitted with pyelonephritis at 34 weeks.
What are your abx options for these 3 infections?
U.T.I. in pregnancy
During pregnancy ureters are dilated and kinked because of :
- increased progesterone relax smooth muscle - obstruction of the lower ureters in late
pregnancyThis encourages : stasis and reflux of infected urine up the ureter
and kidney bladder volume and bladder tone ureteral tone, contribute to urinary stasis and
ureterovesical reflux
Asymptomatic bacteriuria ( colony count< 105) :
Untreated , can lead to cystitis in 30% & pyelonephritis in 50%
Acute cystitis : dysuria, urgency, frequency Acute pyelonephritis: fever, chills, nausea, vomiting
and flank pain.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Treating Asymptomatic Bacteriuria with Antibiotics
* clears bacteriuria * incidence of Pyleonephritis * incidence of premature delivery * incidence of low birth weight baby
U T I in Pregnancy :
Antibiotics throughout pregnancy
Generally considered safe:Penicillin / Ampicillin / Amoxicillin
Nitrofurantoin
Cephalosporins
Clindamycin / Azithromycin / Erythromycin
Antibiotics throughout pregnancy Tetracycline – NEVER PRESCRIBE
Congenital defects, teeth discoloration
Cipro – maybe OK but not usually needed? Mskel fetal abnormalities – not well studiedSecond line for gonorrhea and TB
Bactrim – generally avoided esp in 1st TM Trimethoprim is a folic acid antagonist!
Antibiotics throughout pregnancyUTIs / Asymptomatic bacteruria Nitrofurantoin – Cefpodoxime – Augmentin Always culture and check another to assure
clearance!
Recurrent UTI or bacteruria Post coital or daily Nitrofurantoin or Cephalexin
Pyelonephritis Ceftriaxone or Amp/Gent Continuous prophylaxis until delivery!
Another detour – treating BVMetronidazole orally and topically is safe If symptomatic – tx oral or topical If asymptomatic and no PMH of preterm
birth, there is no evidence of benefit to treatment
If asymptomatic AND PMH pre-term birth – unclear If screening – do so at 1st TM and use Clinda! Metro associated with pre-term birth
Managing common symptoms
A healthy 35 yo G1P0 presents for routine pre-natal care. She complains of daily AM nausea, allergic rhinitis and intermittent GERD throughout the day, worse at night. She is also a smoker – 1ppd and would like to quit.
She is interested in med options for all.
What would you recommend?
Common symptoms of pregnancyAllergic rhinitis
Zyrtec labelled as contraindicated in pregnancy Not well studies, but widely used without issues Topical treatments are first line
URI symptoms Benadryl /dipphenhydramine/ widely considered
safe Dextromethorphan considered safe Guaifenasin /expectorant/associated with neural
tube defects Pseudoephedrine possible association c
gastroschisis
Common symptoms of pregnancyGERD Antacids & H2 blockers considered generally
safe Some recommend avoiding prolonged use of
aluminum or calcium (Maalox) PPIs are also considered safeNausea Ginger, B6 – then Diphenhydramine Promethazine the safest dopamine agonist Prednisone after 10 weeks (palate formation)
“An interesting clinical dilemma…”Smoking cessation Nicotine is FDA pregnancy category D Causes IUGR, premature birth, SAB, SIDS,
etc. etc. Smoking has nicotine + 3000 other
chemicals
Try behavioral techniques first? Use intermittent rather than continuous
replacement