Your Brain Chemistry Will Return to Normal
The combination of L-theanine, Ativan (lorazepam), and hydroxyzine you took will not cause permanent changes to your brain chemistry, and any transient effects will resolve within 24-48 hours as these medications are eliminated from your system.
Why This Combination Is Not Dangerous
Mechanism and Duration of Action
L-theanine is a derivative of glutamate with a very short elimination half-life, and guideline consensus recommends holding it only 24 hours before surgery due to its rapid metabolism 1. The dose-dependent CNS effects are minimal and transient 1.
Lorazepam (Ativan) has predictable pharmacokinetics with complete absorption and no active metabolites, making it one of the safer benzodiazepines 2. While it does cause CNS depression through GABAA receptor binding 3, these effects are temporary and reversible as the drug is metabolized and eliminated.
Hydroxyzine is an antihistamine with anxiolytic properties that, unlike benzodiazepines, actually preserves memory and attention in elderly subjects 4. A comparative study demonstrated that hydroxyzine 25 mg caused minimal sedation without the memory deficits seen with lorazepam 4.
No Synergistic Toxicity
The perioperative guideline specifically addresses theanine and notes it may cause CNS depression, but recommends only a 24-hour hold due to rapid metabolism 1. There is no evidence that combining these three agents causes additive neurotoxicity or permanent neurochemical changes.
Your recent metronidazole treatment for SIBO is not relevant to this interaction, as metronidazole does not significantly interact with benzodiazepines, antihistamines, or L-theanine 5, 6, 7.
Timeline for Resolution
- L-theanine: Eliminated within 24 hours due to rapid metabolism 1
- Lorazepam: Half-life of approximately 12-18 hours; effects diminish within 24-48 hours in patients with normal renal function 3
- Hydroxyzine: Effects typically last 4-6 hours; completely eliminated within 24 hours
You should feel completely back to baseline within 48 hours maximum, likely sooner.
What to Monitor
Watch for excessive sedation or drowsiness over the next 24 hours 3. If you experience prolonged confusion, difficulty breathing, or extreme sedation, seek medical attention immediately.
Avoid taking additional CNS depressants (alcohol, additional benzodiazepines, opioids) during this 48-hour period to prevent additive sedative effects 3.
Common Pitfall to Avoid
Do not assume that temporary sedation or grogginess represents permanent brain damage. The anxiolytic and sedative effects you may be experiencing are the intended pharmacological actions of these medications and will resolve as they are metabolized 1, 3, 4.
If anxiety about medication effects persists beyond 48 hours after complete drug elimination, this likely represents underlying anxiety rather than medication-induced changes, and you should discuss ongoing anxiety management with your provider 8.