Foscarnet & Nutrient Depletion
Also searched as Foscavir. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Foscarnet has been associated with depletion of MAGNESIUM. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Foscarnet long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Foscarnet pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Foscarnet
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.
MAGNESIUM
Moderate DepletionFOSCARNET (Foscavir)
Foscarnet can cause various electrolyte disturbances, including symptomatic hypomagnesemia. This may be due to chelation of magnesium and increased elimination. For information on foods that are rich in magnesium, see our chart.
Magnesium helps keep your muscles, nerves, and heart rhythm working smoothly, so keeping levels in a healthy range really matters. Foscarnet appears to bind to magnesium in the body and pull more of it out through the kidneys than normal, which can drop levels enough to cause noticeable symptoms in some patients. Because this is a well-documented concern with moderate clinical significance, anyone taking foscarnet long-term should have magnesium levels checked regularly, and some people do end up needing a supplement. Talk with your doctor or pharmacist about whether monitoring or supplementation makes sense for you.
What Magnesium does & food sources
Magnesium is involved in muscle and nerve function, heart rhythm, blood sugar control, and bone health.
Common food sources:
- Nuts and seeds (almonds, pumpkin seeds)
- Whole grains
- Leafy green vegetables
- Beans and legumes
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask whether a magnesium level is worth checking if you take an associated medication long-term — particularly with symptoms like muscle cramps, twitching, or palpitations. Blood levels do not always reflect total body stores, which is worth discussing too.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Magnesium supplements come in many forms and can cause loose stools at higher doses. They can also bind some medications in the gut (certain antibiotics, thyroid medication), so timing matters — check with your pharmacist.
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: Magnesium supplementation can be risky in kidney disease, where magnesium can accumulate — always check with a clinician first if your kidney function is reduced.
Learn more about this nutrient: Magnesium — uses, safety & interactions
References (2)
- Gearhart MO, Sorg TB. Foscarnet-induced severe hypomagnesemia and other electrolyte disturbances. Ann Pharmacother 1993;27:285-9..
- Palestine AG, Polis MA, De Smet MD, et al. A randomized, controlled trial of foscarnet in the treatment of cytomegalovirus retinitis in patients with AIDS. Ann Int Med 1991;115:665-73.. PubMed
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 Foscarnet
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.
Foscarnet & nutrients: FAQs
Does Foscarnet deplete MAGNESIUM?
Should I take a supplement because I take Foscarnet?
Should I stop taking Foscarnet?
Where does this information come from?
Questions about Foscarnet and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Foscarnet 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.