Question
The following anesthetic drug causes pain on intravenous administration
| A. | Midazolam |
| B. |
Propofol |
| C. |
Ketamine |
| D. |
Thiopentone sodium |
Show Answer
|
Correct Answer » B Explanation |
 |
- Propofol is the intravenous induction agent most commonly associated with pain on injection.
- Injection pain occurs in approximately 30–70% of patients when administered through small peripheral veins.
- The pain is caused by:
- Irritation of the vascular endothelium.
- Activation of the kallikrein–kinin system, leading to the release of bradykinin, which increases vascular permeability and stimulates pain receptors.
- Injection pain can be reduced by:
- Pretreatment with intravenous lidocaine (lignocaine).
- Using a large vein (e.g., antecubital vein).
- Mixing lidocaine with propofol before administration.
Why the Other Options are Incorrect
Option A. Midazolam
- Midazolam is a benzodiazepine used for sedation and induction.
- Pain on intravenous injection is uncommon.
Option C. Ketamine
- Ketamine is a dissociative anesthetic with analgesic properties.
- Pain on intravenous administration is not a characteristic adverse effect.
Option D. Thiopentone sodium
- Thiopentone is a barbiturate induction agent.
- Although its highly alkaline solution can cause pain, especially with extravasation or inadvertent intra-arterial injection, it is not the intravenous anesthetic most commonly associated with injection pain in current clinical practice.
