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.

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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