The purpose of premedication
Premedication is the administration of medication before anesthesia induction. While historical premedication focused on reducing secretions or managing reflex responses, modern practice primarily centers on improving patient well-being and managing anxiety. A patient's anxiety can increase heart rate and blood pressure, complicating the anesthesia and surgical process. By providing a sedative, the anesthesiologist aims to create a calm and tranquil state, improving the patient's experience and overall surgical outcome.
The most common drug they give you to relax before surgery: Benzodiazepines
Benzodiazepines are the most frequently used class of drugs for managing pre-surgical anxiety. These medications work by depressing the central nervous system, producing sedative and hypnotic effects. A key characteristic of many benzodiazepines used in this setting is their ability to induce anterograde amnesia, meaning the patient often does not remember the time leading up to the procedure.
Key benzodiazepines in preoperative care
- Midazolam (Versed): This is perhaps the most common benzodiazepine given before surgery, known for its rapid onset and short duration of action. It is often administered intravenously, but can also be given orally, especially to children, to reduce anxiety and create amnesia.
- Diazepam (Valium): With a longer history of use, diazepam is another option, though its prolonged half-life means it can lead to longer recovery times. For this reason, it is less frequently used than midazolam for outpatient procedures where a rapid recovery is desired.
- Lorazepam (Ativan): Another benzodiazepine used for anxiety relief, lorazepam has a moderate duration of action and is sometimes used for patients requiring longer anxiolytic effects.
Other pharmacological options for preoperative relaxation
While benzodiazepines are a staple, anesthesiologists may use other agents depending on the patient's specific needs.
Alpha-2 agonists
Clonidine and dexmedetomidine are alpha-2 adrenergic agonists that provide sedation and some analgesia. Dexmedetomidine, in particular, offers a more specific and rapid effect than clonidine, making it a valuable option. Unlike benzodiazepines, alpha-2 agonists do not significantly cause respiratory depression, making them beneficial in certain patient populations.
Melatonin
The sleep hormone melatonin has been studied for its anxiolytic properties before surgery. Some studies suggest it can reduce pre-operative anxiety similarly to benzodiazepines and may be used in specific cases, though it is not a universal solution.
How these drugs work
The primary mechanism of action for sedatives used before surgery involves depressing the central nervous system. For benzodiazepines like midazolam, this is achieved by modulating the gamma-aminobutyric acid (GABA) type A receptor. GABA is the primary inhibitory neurotransmitter in the central nervous system, so by enhancing its effects, benzodiazepines cause a widespread slowing of brain activity, leading to sedation, amnesia, and anxiolysis.
Alpha-2 agonists, like dexmedetomidine, work by stimulating alpha-2 receptors in the brain. This action decreases the release of norepinephrine, reducing the body's stress response and producing sedation and pain relief.
Comparison of preoperative sedatives
| Feature | Midazolam (Versed) | Lorazepam (Ativan) | Dexmedetomidine (Precedex) |
|---|---|---|---|
| Drug Class | Benzodiazepine | Benzodiazepine | Alpha-2 Agonist |
| Onset | Rapid (IV) / 15-20 min (Oral) | 2-3 min (IV) / 60 min (Oral) | 30-40 min (Intranasal) / <1 min (IV) |
| Duration | Short | Long | Short (2 hours) |
| Primary Effect | Sedation, amnesia, anxiety relief | Sedation, anxiety relief | Sedation, some analgesia |
| Administration | IV, Oral, Intranasal, IM | IV, Oral | IV, Intranasal |
| Notes | Most common, rapid onset, good for outpatient. | Slower onset, longer duration, not ideal for rapid recovery. | Useful when respiratory depression is a concern; more specific sedation. |
Patient monitoring and potential side effects
After administering a sedative, the patient is closely monitored by the anesthesiology team to ensure safety. While these medications are generally safe under medical supervision, side effects can occur. Common side effects include dizziness, drowsiness, headache, and confusion. More serious risks, particularly when combined with opioids or other sedatives, include respiratory depression (slowed breathing). Special precautions are taken for pediatric and geriatric patients, who may be more sensitive to a drug's effects.
Non-pharmacological approaches
For many patients, especially those with mild anxiety, non-pharmacological methods can be a valuable adjunct or alternative to medication. These include:
- Patient Education: Providing clear information about the anesthesia plan and what to expect can significantly reduce anxiety.
- Therapeutic Communication: A supportive relationship with the medical staff, especially the anesthesiologist, can be reassuring.
- Distraction Techniques: Using music therapy, guided imagery, or virtual reality can help shift a patient's focus away from their fears.
- Parental Presence: For children, having a parent present during the induction of anesthesia can ease separation anxiety.
Conclusion
In summary, the medication used to relax a patient before surgery is known as a premedication or anxiolytic. The most common medication is midazolam, a benzodiazepine that provides rapid anxiety relief and amnesia. However, the specific drug, dosage, and route of administration are chosen by the anesthesiologist based on a careful assessment of the individual patient's health, age, anxiety level, and the specific surgical procedure. While pharmacological options are effective, non-drug interventions are also valuable for managing preoperative anxiety. The combination of these strategies ensures the patient is as comfortable and calm as possible, setting the stage for a successful procedure.
For more detailed information on anesthetic drugs and patient safety, consult resources from authoritative organizations like the Anesthesia Patient Safety Foundation (APSF).
