Heptabarbital and Amitriptyline: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amitriptyline
Heptabarbital
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
You've been prescribed amitriptyline (an antidepressant) along with heptabarbital (a barbiturate). Here's what's going on: the barbiturate can speed up how fast your body breaks down amitriptyline. That can lower the amount of antidepressant in your blood, so it may not work as well for you.
At the same time, both drugs can make you very sleepy and can slow your breathing when taken together. Amitriptyline can also make seizures a bit easier to trigger. This sounds like a lot, but your care team can manage it by checking how you're doing and adjusting your doses if needed. Please don't change anything on your own, just talk with your doctor or pharmacist.
Effect: Barbiturate-induced hepatic enzyme induction increases metabolism of the TCA, reducing amitriptyline serum levels/exposure and risking loss of antidepressant efficacy.
- Direction: Reduced TCA effect (neither drug is a prodrug; amitriptyline is active as given).
- Additive risks: Combined CNS and respiratory depression; amitriptyline lowers seizure threshold, potentially worsening seizure control.
- Onset: Delayed (induction develops over days to weeks).
- Evidence: Probable; scattered case reports of decreased TCA levels.
- Management: Monitor mood/antidepressant response and TCA levels; watch for excess sedation and respiratory depression. Doses may need individualization by the care team.
What happens
Reduced tricyclic antidepressant exposure and possible additive adverse effects
Interaction Deep Dive
When a barbiturate is taken together with a tricyclic antidepressant (TCA), the metabolism of the TCA may be enhanced. A number of isolated reports describe patients whose TCA serum concentrations dropped while a barbiturate was present123. TCAs may also compromise seizure control because they lower the seizure threshold. Beyond this, both agents produce additive depressant effects on the CNS and respiration4.
Why it happens (mechanism)
Increased tricyclic antidepressant metabolism
How to manage this interaction
This combination can be managed. Keep taking both medications exactly as prescribed unless your care team tells you otherwise.
- Your team may monitor you more closely, watching whether your depression symptoms are still well controlled since the barbiturate can lower antidepressant levels.
- Your amitriptyline dose may need to be adjusted and individualized by your prescriber.
- Watch for heavy drowsiness or slowed/shallow breathing, since both drugs are sedating, and report these.
- Tell your team about any seizure history.
Raise any changes in mood, sleepiness, or breathing with your pharmacist or doctor.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) The pharmacokinetics of a single oral desipramine dose (100 mg) were examined in eight epilepsy patients receiving long-term PHENobarbital therapy and in eight drug-free healthy controls. Every participant was classified as an extensive metabolizer according to the genetically determined CYP2D6-related metabolic polymorphism. Relative to the controls, the epilepsy patients showed reduced peak plasma desipramine levels (74 nmol/L vs. 107 nmol/L), lower desipramine area under the concentration-time curve figures (1943 nmol/L/h vs. 3234 nmol/L/h), and shorter desipramine elimination half-lives (15.1 h vs. 20.6 h). All barbiturates are thought to produce comparable effects that induce hepatic enzymes, and the 2D6 isozyme is thought to be significant in the metabolism of most or all TCAs. Consequently, comparable effects should be anticipated with any pairing of a TCA and a barbiturate 5.
Common questions
Can I take Heptabarbital and Amitriptyline together?
The barbiturate can lower amitriptyline levels and reduce its effect, and together they add to sedation and slowed breathing, so keep both as prescribed and let your care team monitor you and adjust the dose. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Heptabarbital and Amitriptyline interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Heptabarbital and Amitriptyline interaction managed?
This combination can be managed. Keep taking both medications exactly as prescribed unless your care team tells you otherwise. Your team may monitor you more closely, watching whether your depression symptoms are still well controlled since the barbiturate can lower antidepressant levels. Your amitriptyline dose may need to be adjusted and individualized by your prescriber. Watch for heavy drowsin… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Heptabarbital or Amitriptyline need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (5)
- Moody JP, Whyte SF, MacDonald AJ, et al: Pharmacokinetic aspects of protriptyline plasma levels. Eur J Clin Pharmacol 1977; 11:51-56. PubMed
- Silverman G & Braithwaite R: Interaction of benzodiazepines with tricyclic antidepressants (letter). Br Med J 1972; 4:111. PubMed
- Burrows GD & Davies B: Antidepressants and barbiturates. Br Med J 1971; 4:113. PubMed
- Brodie MJ: Drug interactions in epilepsy. Epilepsia 1992; 33(suppl 1):S13-S22. PubMed
- Spina E, Avenoso A, Campo GM, et al: Phenobarbital induces the 2-hydroxylation of desipramine. Ther Drug Monit 1996; 18:60-64. DOI
Keep reading about Amitriptyline
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