25-OH Vitamin D Medication-Driven Changes: What Drugs Raise or Lower Your Level

What the evidence can and cannot tell you

Serum 25-hydroxyvitamin D, or 25(OH)D, is the standard blood measure of vitamin D status, reported in ng/mL or nmol/L with 1 ng/mL equal to 2.5 nmol/L [3]. A drug could shift that number by changing how much vitamin D is absorbed or how it is metabolized.

A 2013 systematic review screened the literature through September 2010 and included 109 reports on drug-vitamin D interactions. Most were nonrandomized trials, case-control, cross-sectional or case reports, and only five were rated positive quality [2].

Atorvastatin appears to raise 25(OH)D

The clearest drug with a raising effect in that review is atorvastatin. The authors report that atorvastatin appears to increase 25(OH)D concentrations, and that taking vitamin D at the same time decreases atorvastatin concentrations. The studies were small and low in quality, and the review called for larger studies [2].

Mineral oil interferes with vitamin D absorption

The prescription ergocalciferol label states that mineral oil interferes with the absorption of fat-soluble vitamins, including vitamin D preparations [1]. That is an absorption statement; the label does not report a measured change in blood 25(OH)D.

Thiazide diuretics change calcium, not mainly the vitamin D reading

Thiazides lower urinary calcium excretion [4]. The 2013 review notes that thiazides combined with calcium and vitamin D supplements may cause hypercalcemia in older adults and in people with kidney impairment or hyperparathyroidism [2]. The ergocalciferol label warns that giving thiazide diuretics to hypoparathyroid patients being treated with ergocalciferol may cause hypercalcemia [1].

The numbers come from a post hoc analysis of a randomized dose-finding trial. It enrolled 328 Black adults (median age 51) who took placebo or 1,000, 2,000 or 4,000 IU of vitamin D3 daily for 3 months, and 84 of them reported hydrochlorothiazide use. At 3 months, hydrochlorothiazide users had serum calcium about 0.2 mg/dL higher than non-users (P<0.001), and one hydrochlorothiazide user had hypercalcemia, against none of the 44 people in the comparison group [4].

The thiazide analysis focused on serum calcium; it does not establish that hydrochlorothiazide raises or lowers 25(OH)D [4].

The classes with no established effect

The same review examined antiepileptic drugs, lipase inhibitors such as orlistat, antiretroviral drugs, antimicrobials and H2 receptor antagonists, and found insufficient evidence to determine whether any of them alter serum 25(OH)D concentrations [2]. That is a statement about the published evidence, not a finding that these drugs leave vitamin D status untouched.

Conditions that raise the active hormone instead

Not every picture that looks like a drug effect is one. Endogenous vitamin D toxicity can develop when granulomatous disorders or some lymphomas produce 1,25-dihydroxyvitamin D, and some people develop hypercalcemia on recommended vitamin D doses through dysregulated vitamin D metabolism [5]. In overdose, hypercalcemia tracks 25(OH)D rather than 1,25-dihydroxyvitamin D [6].

Reading the result in context

A 25(OH)D result on its own needs context. The Institute of Medicine's 2011 committee put 16 ng/mL (40 nmol/L) as covering the requirement of about half the population and 20 ng/mL (50 nmol/L) as covering at least 97.5%; it found values above 30 ng/mL (75 nmol/L) were not consistently associated with more benefit and said values above 50 ng/mL (125 nmol/L) should raise concern about potential adverse effects [7][3]. The Endocrine Society's 2024 guideline no longer endorses its 2011 target of 30 ng/mL, or any specific levels to define sufficiency, insufficiency and deficiency [8].

When a supplement and one of these drugs overlap

The prescription ergocalciferol label says the range between therapeutic and toxic doses is narrow, and it lists hypercalcemia, malabsorption syndrome, abnormal sensitivity to the toxic effects of vitamin D and hypervitaminosis D as contraindications. Its supervised regimens call for blood calcium and phosphorus every 2 weeks [1]. Hypervitaminosis D produces hypercalcemia with confusion, apathy, recurrent vomiting, abdominal pain, polyuria, polydipsia and dehydration, and a 25(OH)D above 150 ng/mL (375 nmol/L) is the hallmark of toxicity from overdosing [5].

Toxicity is rare and has been traced to supplement manufacturing and labeling errors. Two US patients took products containing more than 1,000 times the labeled daily vitamin D3 dose, developed severe hypercalcemia, and needed about a year for 25(OH)D to normalize [6].