Phenolphthalein & Nutrient Depletion
Also searched as Modane, Evac-Q-Tab, Modane Mild. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Phenolphthalein has been associated with depletion of CALCIUM, POTASSIUM and VITAMIN D. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Phenolphthalein long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Phenolphthalein pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Phenolphthalein
Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.
CALCIUM
Moderate DepletionSTIMULANT LAXATIVES
Prolonged use of high doses of stimulant laxatives can reduce dietary calcium and vitamin D absorption, and possibly lead to osteomalacia. Advise patients to limit stimulant laxatives to short-term use of recommended doses.
Calcium is the mineral your bones and teeth depend on, and it also helps your muscles and nerves work properly. Phenolphthalein is a stimulant laxative that speeds up movement through the gut, and when things move too fast, your intestines simply have less time to pull calcium (and vitamin D) out of food before it passes through. With moderate evidence behind this interaction, long-term or high-dose use is where the real concern sits, so if you use this type of laxative regularly, it is worth a conversation with your pharmacist or doctor about whether your calcium intake needs a closer look.
What Calcium does & food sources
Calcium builds and maintains bone and is essential for muscle contraction and nerve signaling.
Common food sources:
- Dairy products (milk, yogurt, cheese)
- Fortified plant milks and juices
- Canned fish with bones (sardines, salmon)
- Leafy greens like kale
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask your provider whether bone health monitoring (and vitamin D testing) makes sense with long-term use of an associated medication — a blood calcium level alone does not capture bone calcium status.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Calcium can interfere with the absorption of several medications (some antibiotics, thyroid medication, iron) — separate the doses and confirm timing with your pharmacist. Total intake from food plus supplements matters more than supplements alone.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Very high calcium intake has its own risks (kidney stones in susceptible people) — more is not better.
Learn more about this nutrient: Calcium — uses, safety & interactions
References (1)
- Frier BM, Scott RD. Osteomalacia and arthropathy associated with prolonged abuse of purgatives. Br J Clin Pract 1977;31:17-9. DOI
POTASSIUM
Moderate DepletionSTIMULANT LAXATIVES
Long-term use of stimulant laxatives, or acute use of high doses (e.g., in bowel-cleansing regimens), can result in potassium loss and hypokalemia. Advise people to only use stimulant laxatives short-term at recommended doses.
Potassium is a mineral your heart, muscles, and nerves depend on to work properly. Phenolphthalein is a stimulant laxative, meaning it pushes your intestines to move faster, and when that happens repeatedly or at high doses, potassium gets swept out through the gut before your body can hold onto it. This is rated a moderate concern, so most short-term users at normal doses are fine, but people who use it regularly over time may need monitoring or even a supplement. If that sounds like your situation, it is worth a conversation with your pharmacist or doctor.
What Potassium does & food sources
Potassium keeps nerve signals, muscle contractions, and heart rhythm working normally.
Common food sources:
- Bananas and citrus fruits
- Potatoes and sweet potatoes
- Beans and lentils
- Tomatoes and leafy greens
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Potassium is routinely checked with basic blood work. If you take a medication associated with potassium loss (like some diuretics), ask your provider how often your electrolytes should be monitored.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Do not start potassium supplements on your own. Both low and high potassium can affect heart rhythm, and several common medications (ACE inhibitors, ARBs, potassium-sparing diuretics) raise potassium.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Potassium supplementation can be dangerous in kidney disease or alongside potassium-raising medications — this is a decision for your prescriber, guided by lab results.
Learn more about this nutrient: Potassium — uses, safety & interactions
References (3)
- Ritsema GH, Ellers G. Potassium supplements prevent serious hypokalemia in colon cleansing. Clin Radiol 1994;49;874-6.
- Murry JJ, Healy MD. Drug-mineral interactions: a new responsibility for the hospital dietician. J Am Diet Assoc 1991;91:66-73.
- Garabedian-Ruffalo SM, Ruffalo RL. Drug and nutrient interactions. Am Fam Physician 1986;33:165-74.
VITAMIN D
Moderate DepletionSTIMULANT LAXATIVES
Prolonged use of high doses of stimulant laxatives can reduce dietary vitamin D and calcium absorption, leading to hypocalcemia and osteomalacia. Advise patients to limit stimulant laxatives to short-term use of recommended doses.
Vitamin D is something your body needs to absorb calcium and keep bones strong, and there is a real concern that long-term use of phenolphthalein, a stimulant laxative, can interfere with how well your gut pulls vitamin D (and calcium) out of food. Essentially, speeding up movement through the intestines leaves less time for these nutrients to be absorbed. This is rated as a moderate depletion, meaning it is not just theoretical, and some people who use this type of laxative regularly do benefit from a supplement. If you are using phenolphthalein for more than a short stretch, it is worth a conversation with your pharmacist or doctor about whether your vitamin D levels should be checked.
What Vitamin D does & food sources
Vitamin D helps the body absorb calcium and supports bone, muscle, and immune health.
Common food sources:
- Fatty fish (salmon, mackerel)
- Fortified milk and cereals
- Egg yolks
- Sunlight exposure (the main natural source)
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
A 25-hydroxyvitamin D blood test is the standard way to assess status — ask whether it is appropriate if you take an associated medication long-term, have limited sun exposure, or have bone concerns.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Vitamin D dosing varies a lot between people; some medications change how vitamin D is processed. Your provider can target a dose to your level instead of guessing.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Vitamin D is fat-soluble and can accumulate — very high doses over time can cause harm, so follow a clinician-guided plan.
Learn more about this nutrient: Vitamin D — uses, safety & interactions
References (1)
- Frier BM, Scott RD. Osteomalacia and arthropathy associated with prolonged abuse of purgatives. Br J Clin Pract 1977;31:17-9. DOI
This tool is educational and is not a substitute for professional medical advice. An association is not a diagnosis and does not mean a deficiency will occur. Always talk to your pharmacist or healthcare provider before starting, stopping, or changing any medication or supplement.
Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center Licensed records refresh weekly · last updated July 3, 2026.
More about Phenolphthalein
What drug-induced nutrient depletion means
Some medications can, over time, lower the levels of certain vitamins, minerals, or other nutrients — through reduced absorption, increased loss, or changes in how the body uses them.
Association is not deficiency
An entry here means a depletion has been reported or studied — not that it happens to everyone, or that you are deficient. Dose, duration, diet, and your own health all matter.
Evidence varies by pair
Some drug–nutrient links (like metformin and vitamin B12) are well studied; others rest on limited or preliminary research. Each entry shows the evidence rating from our licensed clinical database.
When to ask about labs
If you take an associated medication long-term, ask your healthcare provider whether monitoring is appropriate for you. Not everyone needs testing — your provider can weigh your dose, duration, and symptoms.
Don't self-supplement blindly
Supplements are not risk-free: some can interact with medications, and some (like potassium or magnesium) can be risky with kidney disease. Talk to your pharmacist before adding anything.
Never stop a medication over this
These medications are prescribed for good reasons, and the benefit usually far outweighs a manageable nutrient consideration. Any change belongs in a conversation with your prescriber.
Food first, usually
For many nutrients, a varied diet covers the gap. Each entry lists common food sources; a supplement is a decision to make with your pharmacist or provider, not a default.
Phenolphthalein & nutrients: FAQs
Does Phenolphthalein deplete CALCIUM?
Should I take a supplement because I take Phenolphthalein?
Should I stop taking Phenolphthalein?
Where does this information come from?
Questions about Phenolphthalein and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Phenolphthalein are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this page.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for medication overviews across the site.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.