Drugs contraindicated in pregnancy
Reading File
Finding Sources
Finding Sources
Reading File
Reading File
Reading File
Reading File
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Finding Sources
Reading File
I now have comprehensive information from multiple authoritative textbooks. Let me compile the complete answer:
Drugs Contraindicated in Pregnancy
Drugs contraindicated in pregnancy are those proven to cause fetal harm (teratogens), fetal death, or serious obstetric complications. They are grouped below by drug class.
1. Cardiovascular Drugs
| Drug / Class | Fetal Risk |
|---|---|
| ACE inhibitors (enalapril, captopril, lisinopril) | Fetal renal dysgenesis, oligohydramnios, lung hypoplasia, skull ossification defects ("ACE inhibitor fetopathy") - contraindicated in all trimesters |
| Angiotensin receptor blockers (ARBs) (losartan, valsartan) | Same mechanism as ACEi; fetal renal failure, oligohydramnios |
| Angiotensin receptor-neprilysin inhibitors (ARNI) (sacubitril/valsartan) | Contraindicated - same renal risks as ARBs |
| Warfarin | Warfarin embryopathy (nasal hypoplasia, stippled epiphyses) with doses >5 mg in 1st trimester; CNS malformations in 2nd/3rd trimester; fetal hemorrhage |
| Novel oral anticoagulants / NOACs (dabigatran, rivaroxaban, apixaban) | Insufficient safety data; contraindicated throughout pregnancy |
| Amiodarone | Fetal hypothyroidism, goiter, neurodevelopmental abnormalities, QT prolongation; reserved only for maternal emergencies |
| Endothelin receptor antagonists (bosentan, macitentan) | Mandibular malformations, cardiac defects |
| Statins (all HMG-CoA reductase inhibitors) | Teratogenic potential (cholesterol essential for fetal development); contraindicated. Bile acid sequestrants (cholestyramine) are preferred |
| Fibrates (gemfibrozil, fenofibrate) | Teratogenic potential; avoid except in severe hypertriglyceridemia (2nd/3rd trimester only) |
| Atenolol | Associated with fetal growth restriction (higher-risk beta-blocker; labetalol/metoprolol preferred) |
Source: Fuster and Hurst's The Heart, 15th Ed.
2. Antiepileptic Drugs (AEDs)
| Drug | Fetal Risk |
|---|---|
| Valproate / valproic acid | Neural tube defects (spina bifida) 1-4%, facial clefts, cardiac anomalies, cognitive impairment ("fetal valproate syndrome") - highest teratogenic risk of all AEDs |
| Carbamazepine | Neural tube defects (~0.5-1%), facial clefts, cardiac anomalies |
| Phenytoin | Fetal hydantoin syndrome (midface hypoplasia, digit/nail hypoplasia, growth restriction, cognitive impairment) |
| Phenobarbital | Major congenital malformations; neonatal withdrawal; cognitive effects |
| Topiramate | Oral clefts, small for gestational age; contraindicated where avoidable |
| Lamotrigine | Possible oral clefts (some data); preferred AED when treatment is necessary |
Note: Where AEDs cannot be discontinued, the lowest effective dose + folic acid supplementation (5 mg/day) is mandatory. Sources: Maudsley Prescribing Guidelines 15th Ed.; Creasy & Resnik's Maternal-Fetal Medicine; Kaplan & Sadock's Comprehensive Textbook of Psychiatry
3. Psychiatric Drugs
| Drug | Fetal Risk |
|---|---|
| Lithium | Ebstein's anomaly (tricuspid valve malformation); toxicity in neonate; contraindicated especially in 1st trimester |
| Valproate (mood stabilizer use) | As above; clear causal link to fetal abnormalities |
| Carbamazepine (mood stabilizer use) | As above |
| Thalidomide | Classic limb reduction defects (phocomelia), ear/eye anomalies, internal organ defects; absolutely contraindicated |
Sources: Tintinalli's Emergency Medicine; Maudsley Prescribing Guidelines 15th Ed.
4. Retinoids (Vitamin A Derivatives)
| Drug | Fetal Risk |
|---|---|
| Isotretinoin (oral, for acne/Accutane) | Retinoic acid embryopathy - CNS malformations, craniofacial defects, cardiac defects, thymic aplasia; up to 35% risk with 1st trimester exposure; mandatory contraception via iPLEDGE program |
| Acitretin (for psoriasis) | Same retinoic acid embryopathy; stored in fat for years - contraception needed for 3 years after stopping |
| Tazarotene (topical) | Category X topical retinoid |
| High-dose vitamin A (>10,000 IU/day) | Retinoic acid embryopathy |
Source: Creasy & Resnik's Maternal-Fetal Medicine
5. Antibiotics & Antifungals
| Drug | Fetal Risk |
|---|---|
| Tetracyclines | Fetal dental discoloration (yellow-brown staining), enamel hypoplasia, inhibition of bone growth; risk for fatty liver in pregnancy (mother) |
| Fluoroquinolones (ciprofloxacin, levofloxacin) | Cartilage toxicity in animal models; generally avoided, especially in 1st trimester |
| Chloramphenicol (near term) | "Gray baby syndrome" - cardiovascular collapse in neonate |
| Sulfonamides (near term) | Neonatal kernicterus (compete with bilirubin for albumin binding) |
| Podophyllin (topical, for warts) | Teratogenic; podophyllotoxin also avoided |
| Ibrexafungerp | Teratogenic in animal models; contraindicated |
Sources: Creasy & Resnik's Maternal-Fetal Medicine; Goldman-Cecil Medicine; Dermatology 2-Volume Set 5e
6. Cytotoxic / Immunosuppressive Drugs
| Drug | Fetal Risk |
|---|---|
| Methotrexate | Fetal death, neural tube defects, limb abnormalities (anti-folate teratogen); 3-month washout before conception |
| Mycophenolate mofetil | Severe fetal malformations (ear, limb, heart defects); contraindicated |
| Cyclophosphamide | Major structural defects in 1st trimester |
| 5-Fluorouracil (5-FU) | Teratogenic; contraindicated (formerly Category X/D) |
| Thalidomide | (See psychiatric section above; used also in multiple myeloma, Crohn's disease) |
7. Hormonal Agents
| Drug | Fetal Risk |
|---|---|
| Diethylstilbestrol (DES) | Vaginal adenocarcinoma in female offspring, genital tract anomalies |
| Combined oral contraceptives (estrogen-progestin) | Avoid in established pregnancy; generally not acutely teratogenic but should be stopped |
| Androgens / anabolic steroids | Virilization of female fetus |
| Misoprostol (prostaglandin E1) | Uterine contractions, fetal limb defects if pregnancy continues (Mobius syndrome) |
| Danazol | Virilization of female fetus |
8. NSAIDs
| Drug | Risk (especially 3rd trimester) |
|---|---|
| Indomethacin, ibuprofen, naproxen | Premature closure of ductus arteriosus, fetal renal impairment, oligohydramnios; contraindicated after 20 weeks (FDA warning); indomethacin also used short-term as tocolytic - risk-benefit assessment required |
9. Ergot Alkaloids
| Drug | Risk |
|---|---|
| Ergotamine, dihydroergotamine | Oxytocic effects, reduced uterine blood flow; contraindicated despite no proven teratogenicity |
Source: Rosen's Emergency Medicine
Quick Reference: Classic Teratogen-Malformation Pairs (High-Yield)
| Teratogen | Classic Defect |
|---|---|
| Thalidomide | Phocomelia (limb reduction) |
| Isotretinoin | Craniofacial + cardiac + CNS defects |
| Valproate | Neural tube defects (spina bifida) |
| Warfarin | Warfarin embryopathy (nasal hypoplasia, stippled epiphyses) |
| ACEi/ARBs | Fetal renal dysgenesis, oligohydramnios |
| Tetracyclines | Dental staining, bone growth inhibition |
| DES | Vaginal clear-cell adenocarcinoma (daughters) |
| Alcohol | Fetal alcohol syndrome |
| Phenytoin | Fetal hydantoin syndrome |
| Lithium | Ebstein's anomaly |
| Carbamazepine | Neural tube defects, facial clefts |
| Misoprostol | Mobius syndrome, limb defects |
| Androgens | Female fetus virilization |
| Aminoglycosides | Fetal ototoxicity (8th nerve) |
Key clinical principle: The FDA replaced the old A/B/C/D/X letter category system in 2015 with the Pregnancy and Lactation Labeling Rule (PLLR), which requires detailed narrative risk descriptions. However, the letter system remains widely used in clinical education.
Sources: Fuster and Hurst's The Heart 15e, Creasy & Resnik's Maternal-Fetal Medicine, Maudsley Prescribing Guidelines 15e, Kaplan & Sadock's Comprehensive Textbook of Psychiatry, Rosen's Emergency Medicine, Tintinalli's Emergency Medicine, Goldman-Cecil Medicine, Dermatology 2-Volume Set 5e
This is a shared conversation. Sign in to Orris to start your own chat.