Dental local anesthetics containing 2% lignocaine with adrenaline 1 : 80000: A) In any dosage are contraindicated in patients with heart disease B) May cause tachycardia C) Can produce allergic reactions, in which lignocaine is usually responsible D) Or even prilocaine with felypressin should not be used in the pregnant patient because of the oxytocic effects of adrenaline or felypressin. E) Cause hypertensive reactions in patients on tricyclic antidepressants

**Core Concept**
Lignocaine with adrenaline is a commonly used dental local anesthetic, but it has specific contraindications and precautions due to the vasoconstrictive effects of adrenaline. Adrenaline, when administered in large doses or to certain patient populations, can cause significant cardiovascular and systemic effects.

**Why the Correct Answer is Right**
The correct answer, **D**, is right because prilocaine with felypressin is an alternative local anesthetic for pregnant patients. Felypressin is a synthetic analogue of vasopressin, which has a minimal oxytocic effect, making it safer for use during pregnancy. In contrast, adrenaline has a more pronounced oxytocic effect, which can stimulate uterine contractions and potentially lead to preterm labor. This makes option D a safer choice for pregnant patients.

**Why Each Wrong Option is Incorrect**
**Option A:** This statement is incorrect because lignocaine with adrenaline is not contraindicated in all patients with heart disease. However, patients with certain cardiac conditions, such as coronary artery disease or cardiac arrhythmias, may require caution or alternative local anesthetics.

**Option B:** This statement is incorrect because adrenaline can actually cause bradycardia (decreased heart rate) due to its vasoconstrictive effects, rather than tachycardia (increased heart rate).

**Option C:** This statement is incorrect because both lignocaine and adrenaline can cause allergic reactions, but the likelihood of an allergic reaction to lignocaine is relatively low compared to other local anesthetics.

**Option E:** This statement is incorrect because lignocaine is not typically associated with hypertensive reactions in patients on tricyclic antidepressants. In fact, lignocaine can have a synergistic effect with tricyclic antidepressants, potentially leading to increased risk of cardiac arrhythmias.

**Clinical Pearl / High-Yield Fact**
When using local anesthetics during pregnancy, it's essential to choose agents with minimal oxytocic effects to minimize the risk of uterine contractions and preterm labor. Felypressin, a synthetic analogue of vasopressin, is a safer alternative to adrenaline in this context.

**Correct Answer: D. Prilocaine with felypressin should be used in the pregnant patient because of the oxytocic effects of adrenaline or felypressin.**

✓ Correct Answer: A. Option B is true and ACDE are false