Amitriptyline and Estropipate: 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
Estropipate
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're taking amitriptyline (a tricyclic antidepressant) along with estropipate (an estrogen). When these two are used together, the estrogen may slow down how your liver breaks down the amitriptyline, so more of it can build up in your body.
That can lead to a strange mix: on one hand, the antidepressant may seem to work less well, and on the other, you may notice more side effects like drowsiness, dizziness when standing up, or restlessness. This is more likely if you were already stable on amitriptyline and then started the estrogen. The good news is this is considered a minor interaction, and your care team can manage it by adjusting your doses if needed. Let them know if anything feels off.
Effect: Estrogens may inhibit hepatic metabolism of amitriptyline, increasing TCA exposure. Paradoxically, patients can show simultaneous loss of antidepressant efficacy and signs of TCA toxicity (drowsiness, orthostatic hypotension, akathisia).
- Mechanism: Possible inhibition of hepatic CYP-mediated TCA metabolism; effect appears estrogen dose-related.
- Onset: Delayed. Evidence: Established (isolated cases). Severity: Minor.
- At-risk group: Patients stabilized on amitriptyline who initiate estropipate.
- Management: Monitor for altered TCA response; downward dose adjustment of either agent may restore efficacy or resolve toxicity. Withdrawal occasionally required.
What happens
Possible attenuation of antidepressant effectiveness; tricyclic toxicity (drowsiness, hypotension, akathisia)
Interaction Deep Dive
Estrogens have, in a small number of instances, been reported to either enhance or diminish the pharmacologic activity of tricyclic antidepressants3. Notably, a paradoxical presentation can occur in which the antidepressant benefit is lost while signs of tricyclic toxicity emerge at the same time 1. This interaction seems to depend on the estrogen dose 2, and its clinical relevance is likely greatest in patients already stabilized on tricyclic treatment who then begin estrogen therapy 6.
Why it happens (mechanism)
Possible inhibition of hepatic metabolism of the tricyclic antidepressant
How to manage this interaction
Keep taking both medications as prescribed unless your prescriber tells you otherwise. This interaction is manageable, and your care team knows how to handle it.
- Watch for changes: tell your team if your depression seems to worsen, or if you notice more drowsiness, dizziness on standing, or restlessness.
- Dose may be individualized: if symptoms appear, your team may adjust the dose of either the amitriptyline or the estrogen to restore the right balance.
- Timing matters: this is most relevant when starting estropipate after being stable on amitriptyline, so mention any recent changes.
Do not stop or change either drug on your own; check with your pharmacist or doctor first.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
7 reports — tap to read
a) Certain studies looked at the qualitative outcomes of giving estrogen together with TCAs. In one trial, 30 depressed female prisoners were randomized into four treatment groups. Ten patients were given placebo, 10 received imipramine (150 mg daily) plus placebo, five patients received imipramine (150 mg daily) plus ethinyl estradiol (50 mcg daily), and five patients received imipramine (150 mg daily) plus ethinyl estradiol (25 mcg daily). The 10 patients on placebo showed no improvement across the six weeks of the study. The 10 patients on estrogen and imipramine showed a significantly greater symptom improvement than the 10 patients on imipramine alone. However, after two weeks, the five patients on imipramine and high-dose estrogen had improved less than those on imipramine and low-dose estrogen. The sole side-effect reported was drowsiness, which occurred only in patients taking imipramine. After ethinyl estradiol was stopped, a period of two weeks was needed for the high-dose estrogen group to perform as well as the low-dose group. This effect was ascribed to residual estrogen remaining in the high-dose group. In a separate group, five women receiving imipramine 150 mg and ethinyl estradiol 50 mrg daily improved less than 10 patients receiving imipramine alone. In addition, the patients on the combination experienced severe side-effects, including lethargy, coarse tremor, and systolic hypotension 1.
b) A 32-year-old woman on conjugated estrogens 2.5 mg and imipramine 100 mg developed lethargy, tremors, and signs of depersonalization. After two years of treatment, the patient raised her estrogen dose to 5 mg and then to 7.5 mg daily. She became nauseated, had continuous headaches, and low normal blood pressure. All laboratory results were normal. When the estrogen was stopped, the side effects subsided. Some investigators have suggested that the side effects arose from enhanced TCA effects caused by estrogen inhibiting hepatic microsomal enzymes 32.
c) In a study, women received clomipramine with oral contraceptives or clomipramine alone. At the start of the study 30 women were taking the combination, but 12 later dropped out. The 18 patients on the combination were matched with 18 patients on clomipramine alone. No significant difference was found in the patients' responses to clomipramine. It was proposed that there was no significant difference in side-effects between the groups; however, the groups were matched after patients had dropped out of the study. Had the patients been matched before the study, different conclusions might have been reached 4.
d) The influence of oral contraceptives on clomipramine was examined in 42 women aged 18 to 40. Twenty-three women took clomipramine 25 mg at bedtime, while 19 took clomipramine 25 mg at bedtime along with oral contraceptives. Over the four-week study, three control patients (two because of side-effects) and five in the experimental group (two because of side-effects) dropped out. Venous blood samples were collected weekly to measure serum clomipramine concentrations. No difference in serum concentrations was seen between the groups. However, this finding may be partly attributable to the low dose of clomipramine used 5.
e) The development of akathisia was reported in 3 patients receiving conjugated estrogens together with tricyclic antidepressants. A 24-year-old patient taking clomipramine 120 mg daily for anorexia nervosa and conjugated estrogens 1.25 mg daily for amenorrhea developed restless legs and a persistent urge to keep moving. Estrogen was stopped and benztropine 2 mg was given, producing marked reduction and resolution within 48 hours. Akathisia and disorientation arose in a 55-year-old patient on conjugated estrogen 1.25 mg daily who was prescribed amitriptyline 50 mg daily for depression. Within hours of amitriptyline, the patient was confused, restless, and had an inner urge to move continuously. Symptoms resolved after amitriptyline was discontinued. A third case of akathisia occurred in a 35-year-old patient receiving conjugated estrogen 1.25 mg daily and amitriptyline 50 mg daily. Akathisia developed within a few hours after the first amitriptyline dose and resolved within 48 hours after the antidepressant was stopped 6.
f) The absolute bioavailability of imipramine rose in women receiving low-dose oral contraceptives (50 mcg or less of ethinyl estradiol) from 27% to 44% (p less than 0.05), as shown by an increase in the area under the plasma concentration time curve 7.
g) Estrogens may inhibit the oxidation of TCAs through effects on hepatic microsomal enzymes 8. Many TCAs are metabolized by oxidation and conjugation pathways. Inhibiting the oxidation of TCAs could lead to accumulation and toxicity because of reduced clearance. Estrogens are suspected of having additional central nervous system effects that produce an antidepressant effect 9.
Common questions
Can I take Amitriptyline and Estropipate together?
Estrogen can raise amitriptyline levels, which may cause more tricyclic side effects while the antidepressant seems less effective. This is a minor, manageable interaction, so report any changes and let your care team adjust the doses if needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Estropipate interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Amitriptyline and Estropipate interaction managed?
Keep taking both medications as prescribed unless your prescriber tells you otherwise. This interaction is manageable, and your care team knows how to handle it. Watch for changes: tell your team if your depression seems to worsen, or if you notice more drowsiness, dizziness on standing, or restlessness. Dose may be individualized: if symptoms appear, your team may adjust the dose of either the am… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Amitriptyline or Estropipate 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 anything you'd monitor while I'm on both?
References (9)
- Prange AJ Jr: Estrogens may well affect response to antidepressants. JAMA 1972; 219:143-144.
- Khurana RC: Estrogen-imipramine interaction (letter). JAMA 1972; 222:702-703. PubMed
- Somani SM & Khurana RC: Mechanism of estrogen-imipramine interaction (letter). JAMA 1973; 223:560. DOI
- Beaumont G: Drug interactions with clomipramine. J Int Med Res 1973; 1:480-484.
- Luscombe DK & John V: Influences of age, cigarette smoking and the oral contraceptive on plasma concentrations of clomipramine. Postgrad Med J 1980; 56(suppl 1):99-102.
- Krishnan KR, France RD, & Ellinwood EH: Tricyclic-induced akathisia in patients taking conjugated estrogens. Am J Psychiatry 1984; 141:696-697. PubMed
- Abernethy DR, Greenblatt DJ, & Shader RI: Imipramine disposition in users of oral contraceptive steroids. Clin Pharmacol Ther 1984; 35:792-797. PubMed
- John VA, Luscombe DK, & Kemp H: Effects of age, cigarette smoking and the oral contraceptive on the pharmacokinetics of clomipramine and its desmethyl metabolite during chronic dosing. J Int Med Res 1980; 8(suppl 3):88-95.
- Oppenheim G: Estrogens in the treatment of depression: neuropharmacological mechanisms. Biol Psychiatry 1983; 18:721-725.
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