Drug & supplement interaction

Shark Liver Oil + Pentoxifylline

Pentoxifylline brand name: Trental.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Shark Liver Oil and Pentoxifylline in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Pentoxifylline states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Shark Liver Oil and Pentoxifylline

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Pentoxifylline and Shark Liver Oil in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

Worth understanding: our licensed dataset holds no drug-interaction record for Shark Liver Oil at all — not against Pentoxifylline, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Shark Liver Oil safety at a glance

Shark Liver Oil overall Use caution Generally tolerated short-term but human safety data are limited and product quality varies.
Pregnancy Avoid Not enough safety data; avoid use during pregnancy.
Breastfeeding Avoid Not enough safety data; avoid while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Pentoxifylline and Shark Liver Oil? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Shark Liver Oil and Pentoxifylline May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes / Liver problems Worth acting on Additional detail

    Shark Liver Oil

    “Orally, a case of severe acute hepatitis probably related to use of shark liver oil twice daily for 2 weeks has been reported. The patient presented with abdominal discomfort, jaundice, malaise, pruritus, and elevated levels of bilirubin and liver enzymes. Other potential causes were ruled out.”

    Shark Liver Oil · Natural Medicines adverse-effect record, reported in hepatitis.

    1 source cited
    1. 94285. Kilincalp S, Deveci M, Basar O, Ekiz F, Coban S, Yuksel O. Shark liver oil: hidden dangers. Ann Hepatol. 2012 Sep-Oct;11(5):728-30. DOI

    Pentoxifylline

    Listed in the ADVERSE REACTIONS section of the FDA label for Pentoxifylline. Read the label on DailyMed ›

  • Tiredness / Stomach upset / Itching reported in 10.5% of FDA reports for Pentoxifylline Additional detail

    Shark Liver Oil

    Recorded for Shark Liver Oil in the same Natural Medicines adverse-effect record shown under Yellowing of the skin or eyes / Liver problems above.

    Pentoxifylline

    Listed in the ADVERSE REACTIONS section of the FDA label for Pentoxifylline, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Shark Liver Oil but not commonly for Pentoxifylline: a higher chance of infection.

Effects for Pentoxifylline come from the ADVERSE REACTIONS section of its FDA label; effects for Shark Liver Oil come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 4,245 voluntary FDA FAERS reports for Pentoxifylline that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Pentoxifylline Products Have a Food Rule — Shark Liver Oil Should Not Break It

At least one FDA label for a product containing Pentoxifylline says to take it with food. If you take Shark Liver Oil on an empty stomach out of habit, keep them separate — and take Pentoxifylline with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Pentoxifylline products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

DOSAGE AND ADMINISTRATION The usual dosage of pentoxifylline in extended-release tablet form is one tablet (400 mg) three times a day with meals.

From the Dosage and Administration section of the FDA label we read for Pentoxifylline — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Pentoxifylline

This page covers Shark Liver Oil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Pentoxifylline page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Piracetam (major), Aconite (moderate) and Allspice (moderate).

By severity: 3 major · 190 moderate · 25 minor.

From our pharmacist’s overview on the Pentoxifylline page

“Pentoxifylline (Trental) improves blood flow in people with poor leg circulation partly by making platelets less sticky, so treat this list as one to read carefully rather than skim. Of the 218 supplements on file, 202 can also slow clotting, which means adding them stacks bleeding risk on bleeding risk.”

Reviewed by 2 · Jul 18, 2026

Open the Pentoxifylline interaction page

One more smart check

Taking Shark Liver Oil as Part of a Dietary Supplement Product? Check It for Interactions

We hold 20 real supplement products containing Shark Liver Oil, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Shark Liver Oil. Even though Shark Liver Oil itself has no known interaction with Pentoxifylline, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Shark Liver Oil and Pentoxifylline 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 Shark Liver Oil
Steady interest

#1,042 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Pentoxifylline
Top half

#837 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Shark Liver Oil reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Shark Liver Oil and Pentoxifylline records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Shark Liver Oil

What is Shark Liver Oil?

  • Immune support
  • Skin conditions and wound healing
  • Cancer support (unproven)
  • Hemorrhoid relief (topical)
  • Cold and flu prevention
  • General wellness tonic

Shark liver oil is taken from the livers of deep-sea sharks and is rich in compounds called alkylglycerols and squalene. People use it for immune support, skin healing, and other conditions, but strong human evidence is largely lacking. Talk to your pharmacist or doctor before using it, especially since sustainability and contamination are concerns.

Liver oil from deep-sea sharks · Capsules, softgels, liquid oil, topical creams and ointments

An interaction check asks whether these two react with each other — it does not ask whether Shark Liver Oil is a good idea for someone in your situation. Here is what our Shark Liver Oil record says about it on its own.

Shark Liver Oil: dosing

There is no official or well-established dose for shark liver oil. Products differ in how much alkylglycerol or squalene they contain, so amounts on labels vary.The safest approach is to follow the directions on the product label and not take more than recommended.

From our Shark Liver Oil monograph — the full record covers uses, side effects and every documented interaction.

Read the full Shark Liver Oil monograph & all interactions
Medication

About Pentoxifylline

What Is Pentoxifylline Used For?

Brand name: Trental

Pentoxifylline Extended-Release Tablets are used to treat intermittent claudication — leg pain, cramping, or fatigue that happens during walking because narrowed arteries aren't delivering enough blood to the muscles. The underlying cause is chronic occlusive arterial disease, a condition where the arteries in the limbs become blocked or narrowed over time.

Pentoxifylline can help improve walking distance and reduce symptoms, but it is not a substitute for procedures that physically open or bypass blocked arteries when those treatments are needed.

Most-Reported Side Effects for Pentoxifylline

From FAERS, the FDA’s public side-effect reporting system (4,300 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 457 reports
Diarrhea 431 reports
Dyspnea 405 reports
Fall 376 reports
Dizziness 371 reports
See full Pentoxifylline drug information
Keep checking

Other Drugs & Shark Liver Oil

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

0Major
0Moderate
0Minor
2,829No known interaction
No interaction 2,829 drugs checked — show the list
Evidence & sources

Shark Liver Oil References

The 6 references that drive our Shark Liver Oil monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Lee JY, Lee KS, Kim TS, et al. Squalene-induced extrinsic lipoid pneumonia: serial radiologic findings in nine patients. J Comput Assist Tomogr 1999;23:730-5. PubMed
  2. Lee JS, Im JG, Song KS, et al. Exogenous lipoid pneumonia: high-resolution CT findings. Eur Radiol 1999;9:287-91. PubMed
  3. Asnis DS, Saltzman HP, Melchert A. Shark oil pneumonia. An overlooked entity. Chest 1993;103:976-7.
  4. Deniau AL, Mosset P, Pédrono F, Mitre R, Le Bot D, Legrand AB. Multiple beneficial health effects of natural alkylglycerols from shark liver oil. Mar Drugs. 2010 Jul 19;8(7):2175-84. PubMed
  5. Kilincalp S, Deveci M, Basar O, Ekiz F, Coban S, Yuksel O. Shark liver oil: hidden dangers. Ann Hepatol. 2012 Sep-Oct;11(5):728-30. DOI
  6. Hamadate N, Matsumoto Y, Seto K, Yamamoto T, Yamaguchi H, Nakagawa T, Yamamoto E, Fukagawa M, Yazawa K. Vascular effects and safety of supplementation with shark liver oil in middle-aged and elderly males. Exp Ther Med. 2015 Aug;10(2):641-646. Epub 2015 J PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Shark Liver Oil and Pentoxifylline Together: Common Questions

Is it safe to take Shark Liver Oil with Pentoxifylline?
We do not list a known interaction between Shark Liver Oil and Pentoxifylline. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Shark Liver Oil and Pentoxifylline have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Shark Liver Oil and Pentoxifylline at the same time of day?
At least one FDA label for a product containing Pentoxifylline says to take it with food. If you take Shark Liver Oil on an empty stomach out of habit, keep them separate and take Pentoxifylline with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Pentoxifylline products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Does Pentoxifylline interact with any supplements?
Yes. Pentoxifylline has documented interactions with 218 supplements in our database — Shark Liver Oil is not one of them. The Pentoxifylline interaction page linked on this page lists every one, ranked by severity.

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

Still Have a Question About Pentoxifylline and Shark Liver Oil?

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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.