Drug & supplement interaction

Lithium + Diltiazem, Enalapril

Diltiazem, Enalapril brand name: Teczem.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Diltiazem, Enalapril falls into 2 drug categories that Lithium can interact with; the most serious is rated moderate. Theoretically, taking lithium supplements with ACEIs might increase levels and adverse effects of lithium.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Lithium and Diltiazem, Enalapril

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Lithium interacts with whole categories of medication. Diltiazem, Enalapril falls into 2 of those categories, so it can interact with Lithium in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

ACE INHIBITORS (ACEIs)

1 of 2

Why this applies to Diltiazem, Enalapril

Diltiazem, Enalapril falls under ACE INHIBITORS (ACEIs) — the group Lithium interacts with.

Theoretically, taking lithium supplements with ACEIs might increase levels and adverse effects of lithium.
Concomitant administration of ACEIs with lithium may increase lithium concentrations. It is unclear if this interaction would be clinically significant with the smaller doses found in lithium supplements.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version for Teczem, which is a combo pill containing enalapril (an ACE inhibitor for blood pressure) and diltiazem (a calcium channel blocker). The enalapril half is the piece that matters here. ACE inhibitors can change how your kidneys handle sodium and water, and in theory that can cause your body to hold onto more lithium. When lithium builds up, you may notice things like shakiness, nausea, a fine tremor, confusion, or feeling unsteady.

I'll be honest: this is a theoretical concern based on how these drugs behave, not proven harm, and the tiny amounts in mood supplements like lithium orotate may not matter much. Still, lithium has a narrow safe range, so please check with your pharmacist or doctor before combining them rather than guessing.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
  2. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
Moderate

CALCIUM CHANNEL BLOCKERS

2 of 2

Diltiazem, Enalapril also falls under CALCIUM CHANNEL BLOCKERS.

Theoretically, taking lithium supplements with calcium channel blockers might reduce lithium levels and might also increase the risk of certain adverse effects.
Calcium channel blockers might reduce lithium concentrations. Monitor lithium levels with concurrent use. Calcium channel blockers might also increase the adverse neurological and gastrointestinal adverse effects of lithium. It is unclear if these interactions would occur with the smaller doses found in lithium supplements.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Teczem is a combo pill, with diltiazem (a calcium channel blocker that relaxes blood vessels and slows the heart) plus enalapril (an ACE inhibitor that lowers blood pressure). The piece that interacts here is the diltiazem part. On paper, combining a calcium channel blocker with lithium can push lithium levels around. Sometimes lithium levels may drop, and at other times people report more of lithium's nervous-system and stomach side effects, like tremor, dizziness, confusion, nausea, or diarrhea.

Keep in mind this is a theoretical concern based mostly on how the drugs work, not strong human studies, and it's unclear if the tiny amounts in lithium supplements matter at all. Still, lithium has a narrow safe range, so please check with your pharmacist or doctor before pairing these, and don't change anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Martindale W. Martindale the Extra Pharmacopoeia. Pharmaceutical Press, 1999.
  2. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Lithium Also Interacts With Other Medications

Lithium has 259 major, 255 moderate known drug interactions in our database — the Diltiazem, Enalapril one above is among them. If you take anything else, check it against the full list below.

Major 259 Moderate 255 No known interaction 2,316 (incl. Diltiazem, Enalapril)
Taking anything else?

Check Another of Your Medications Against Lithium

Covers the 2,830 medications we’ve checked against Lithium. Pick one to open its full report.

From our Q&A

Questions About Lithium or Diltiazem, Enalapril

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Lithium or Diltiazem, Enalapril, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Diltiazem, Enalapril

This page covers Lithium only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diltiazem, Enalapril page lists 271 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Coleus (major).

By severity: 9 major · 220 moderate · 42 minor.

From our pharmacist’s overview on the Diltiazem, Enalapril page

“Anyone taking Teczem (diltiazem with enalapril) for blood pressure should know that most of the 271 supplements with an interaction on file hit the same targets as the drug itself. The bulk either add to its blood-pressure-lowering effect or change how the body handles diltiazem, which is processed by an enzyme called CYP3A4.”

Reviewed by 2 · Jul 18, 2026

Open the Diltiazem, Enalapril interaction page

One more smart check

Taking Lithium as Part of a Dietary Supplement Product? Check It for Interactions

We hold 330 real supplement products containing Lithium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lithium. Your product may carry other ingredients that interact with Diltiazem, Enalapril too, on top of Lithium — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Lithium and Diltiazem, Enalapril Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Lithium
Top 25%

#256 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Diltiazem, Enalapril
Top half

#1,223 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Lithium

What is Lithium?

Lithium
  • Mood support
  • Bipolar disorder (prescription)
  • Healthy mental function
  • Irritability or stress
  • Sleep support

Lithium is a naturally occurring metal that, in prescription form (lithium carbonate or citrate), is an FDA-approved, well-proven treatment for bipolar disorder. Low-dose supplement forms like lithium orotate are sold for mood support, but there is very little reliable evidence that they work, and even small amounts of lithium can be risky for some people. Always talk to a pharmacist or doctor before taking any lithium product.

Read the full Lithium monograph & all interactions
Keep checking

Other Drugs & Lithium

Browse every other medication we’ve checked against Lithium — both the ones with a known interaction and the ones without. Select any drug for the full detail.

259Major
255Moderate
0Minor
2,315No known interaction
259 Major 255 Moderate 2,315 No interaction
Major

259 interactions

Showing 60 of 259 major interactions — see all 259 on the Lithium page.

Moderate

255 interactions

Showing 60 of 255 moderate interactions — see all 255 on the Lithium page.

No interaction 2,315 drugs checked — show the list

We also checked Lithium against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,315 medications checked with no known interaction — see the full Lithium list.

See the full Lithium interactions page
See every supplement checked against Diltiazem, Enalapril, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Lithium monograph › Uses, safety, and every drug interaction in one place Diltiazem, Enalapril supplement interactions › Every supplement checked against Diltiazem, Enalapril, ranked by severity Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Lithium and Diltiazem, Enalapril Together: Common Questions

Can you take Lithium with Diltiazem, Enalapril?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for Lithium and Diltiazem, Enalapril?
Diltiazem, Enalapril belongs to more than one drug category, and Lithium interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Lithium and Diltiazem, Enalapril interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Diltiazem, Enalapril and Lithium?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.