Below is a **concise but complete, exam-ready note** on **Drugs in Pregnancy – Antibiotics, Anticoagulants, Antiepileptics**.
Structured for **quick revision + maximum coverage**.

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# ⭐ **DRUGS IN PREGNANCY – DETAILED NOTE (ANTIBIOTICS, ANTICOAGULANTS, ANTIEPILEPTICS)**





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# 1️⃣ **ANTIBIOTICS IN PREGNANCY**

### ✔ **SAFE (Preferred)**

| Class | Examples | Why Safe | Key Uses |
| ------------------ | --------------------------------- | ----------------------- | ------------------------- |
| **Penicillins** | Ampicillin, Amoxicillin, Pen G | No teratogenicity | UTI, GBS prophylaxis |
| **Cephalosporins** | Cefalexin, Ceftriaxone | Broad safety | Pyelonephritis, sepsis |
| **Macrolides** | Azithromycin (best), Erythromycin | Safe except clarithro | Atypical infections, STIs |
| **Clindamycin** | — | Safe | BV, dental infections |
| **Metronidazole** | After 1st trimester | No major teratogenicity | BV, trichomoniasis |
| **Nitrofurantoin** | Avoid near term | Hemolysis risk in G6PD | UTI in early pregnancy |

### ⚠ **USE WITH CAUTION**

| Class | Concern |
| -------------- | ----------------------------------------- |
| **Vancomycin** | Safe but reserve for resistant infections |
| **Linezolid** | Limited data |
| **Daptomycin** | Limited data |

### ❌ **CONTRAINDICATED**

| Drug | Reason |
| -------------------- | ------------------------------------------- |
| **Tetracyclines** | Teeth discoloration, bone growth inhibition |
| **Fluoroquinolones** | Cartilage damage |
| **Aminoglycosides** | Ototoxicity (esp. Streptomycin) |
| **Chloramphenicol** | Gray baby syndrome |
| **Sulfonamides** | Kernicterus near term |

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# 2️⃣ **ANTICOAGULANTS IN PREGNANCY**




## ✔ **SAFE (Preferred)**

### **Low Molecular Weight Heparin (LMWH)**

* **Examples:** Enoxaparin, Dalteparin
* **Mechanism:** Enhances antithrombin → inhibits **Xa** predominantly
* **Does NOT cross placenta → safest anticoagulant**
* **Uses:** DVT/PE treatment, prophylaxis, thrombophilia, APS
* **Monitoring:** Anti-Xa levels in special cases (obesity, renal disease)

### **Unfractionated Heparin (UFH)**

* Safe (does not cross placenta)
* Preferred **near delivery** (shorter half-life, reversible with protamine)

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## ❌ **CONTRAINDICATED**

### **Warfarin**

* Crosses placenta → **warfarin embryopathy** (6–12 weeks):

* Nasal hypoplasia
* Stippled epiphyses
* Limb hypoplasia
* CNS anomalies
* **Fetal hemorrhage** anytime
* **Allowed only in very special cases:** mechanical heart valves when LMWH fails.

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## ⚠ **NEW ORAL ANTICOAGULANTS (NOACs / DOACs)**

Apixaban, Rivaroxaban, Dabigatran

* **Avoid in pregnancy** → insufficient safety, crosses placenta

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# 3️⃣ **ANTIEPILEPTICS IN PREGNANCY**





## ⭐ **KEY PRINCIPLES**

* Goal: **Seizure control** (maternal seizures are more harmful than drug risk)
* Use **monotherapy** at **lowest effective dose**
* Supplement **Folic acid 4–5 mg/day preconception → 1st trimester**
* Check drug levels in pregnancy (pharmacokinetics change)

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## ✔ **RELATIVELY SAFE ANTIEPILEPTICS (Preferred)**

### **1. Lamotrigine**

* Safest among AEDs
* **Teratogenic risk:** Low
* **PK:** Increased clearance → dose adjustment needed
* **Adverse:** Rash (SJS risk)

### **2. Levetiracetam**

* Very safe
* Minimal teratogenicity
* Well-tolerated

### **3. Carbamazepine (with caution)**

* Moderate teratogenic risk
* Associated with **neural tube defects (NTD)** (~1%)
* Give **high-dose folic acid**

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## ⚠ **USE WITH CAUTION**

| AED | Risk |
| ----------------- | ---------------------------------------------------------------------- |
| **Phenytoin** | Fetal hydantoin syndrome: growth delay, facial anomalies, limb defects |
| **Topiramate** | Cleft lip/palate |
| **Phenobarbital** | Cognitive defects, withdrawal |

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## ❌ **AVOID / HIGHLY TERATOGENIC**

### **Valproic Acid**

* **Highest risk of neural tube defects (5–10%)**
* Cognitive impairment
* Cardiac defects
* Dose-dependent teratogenicity
* **Avoid in pregnancy unless no alternative**

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# 4️⃣ **IMPORTANT COMPARISON TABLES**

## **A. Safe vs Unsafe Antibiotics**

| Safe | Unsafe |
| ------------------------------ | -------------------------- |
| Penicillins | Tetracycline |
| Cephalosporins | Fluoroquinolones |
| Azithromycin | Aminoglycosides (ototoxic) |
| Metronidazole (after 1st tri) | Chloramphenicol |
| Nitrofurantoin (not near term) | Sulfonamides (near term) |

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## **B. Safe vs Unsafe Anticoagulants**

| Safe | Unsafe |
| ---- | -------- |
| LMWH | Warfarin |
| UFH | NOACs |

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## **C. Safe vs High-Risk Antiepileptics**

| Safer | Moderate | High-risk |
| ------------- | ------------- | ------------- |
| Lamotrigine | Carbamazepine | Valproate |
| Levetiracetam | Phenytoin | Phenobarbital |
| — | Topiramate | — |

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# 5️⃣ **MANAGEMENT SUMMARY IN PREGNANCY**

### 🔹 **Infection**

* Prefer beta-lactams
* Avoid teratogenic antibiotics
* Treat aggressively because **maternal sepsis harms fetus more**

### 🔹 **Thromboembolism**

* **LMWH first-line**
* Switch to UFH close to delivery
* Avoid warfarin except mechanical valves requiring high-intensity anticoagulation

### 🔹 **Epilepsy**

* Continue AEDs (never stop abruptly)
* Choose **Lamotrigine or Levetiracetam**
* Avoid **Valproate**
* High-dose folic acid (4–5 mg/day)

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