You may choose not to eat meat or not to purchase items made from animals, but there’s one place where avoiding animal products is nearly impossible: the medicine cabinet.

There’s a surprising number of animal products in pharmaceuticals, presenting vegans with a serious dilemma: weighing their health against their principles.

"Medicine is one of the more difficult products for vegans to avoid, especially if something is life-threatening. How far are you prepared to go for your own convictions?" vegan Reuben Proctor writes in "Veganissimo A to Z," a guide to more than 2,500 substances with animal origins that he co-authored with Lars Thomsen.

The most common animal derivative in medicine is lactose, which is used as a carrier, stabilizer or to add bulk. Gelatin, which is derived from the skin and bone of animals, also appears in many capsules and tablets.

Some pills are bound with animal-based substances, such as magnesium stearate, while others may contain dyes that come from cochineal, or carmine, a red dye made from insects.

Vegans also have to consider active ingredients in drugs like insulin, amino acid infusions and anticoagulents. Even medicines that don’t contain animal derivatives aren’t technically animal-free because laws and regulations dictate that medicine must be tested on animals before it’s approved for human use.

The dilemma

According to a 2012 study in the BMJ Postgraduate Medical Journal, 43 percent of the 500 patients surveyed "would prefer not to take animal product-containing medication, even if no alternative were available."

Still, less than a quarter of those patients asked the doctor or pharmacist about their drugs’ composition.

"Alternatives are not always easily available," said Nicki Desai Vishi, a clinical pharmacist at Walter Reed National Military Medical Center. "In some instances, there is only one medication option. Keep in mind that treating the condition, in some instances, may be more important than avoiding animal products — even for vegetarians and vegans."

When Proctor underwent surgery, his doctor said he’d require heparin, an anticoagulant made from pigs’ intestinal membranes. Proctor asked if there was a synthetic substitute, and while his doctor said there was, his doctor also advised him that using it would increase the risk of hemorrhage. Proctor opted to use heparin for 24 hours.

But for some vegans, taking a medication that contains animal products isn’t a one-time occurrence, and the decision can be a difficult one.

"From an ethical standpoint, I believe in veganism, but from a health standpoint, that's a problem for me,” said one vegetarian who asked not to be named. “None of the synthetic drugs I took for thyroid disease and other autoimmune disorders worked."

She currently takes Armour, which is manufactured from the thyroids of pigs.

"For now, I choose to take the Armour and try to live as ethically as possible. But I don't feel comfortable with the decision, nor do I feel that I'm being true to myself. It's a difficult line to walk, but it's also the best compromise I've been able to find."

Why aren’t there more alternatives?

Proctor says there are many vegan food and cosmetics products on the market, but vegan medicine is a tougher sell to companies.

"I doubt the pharmaceutical industry is interested," he told NPR. "They have a totally different paradigm. They don't have qualms about using animals for testing or in products."

Pharmacist Ananth Anthes says pursuing synthetics would also be "financially burdensome to an already strained industry."

"Medications are expensive enough already with economies of scale and workflows and supply chains that are very sensitive," he said.

What you can do

People for the Ethical Treatment of Animals (PETA) provides a list of animal ingredients and their alternatives; however, Vishi says the best way to determine if a medication contains animal products is to ask your physician or pharmacist.

Depending on the medication, pharmacists can sometimes refer patients to compounding pharmacies that can customize medications without certain fillers, byproducts or dyes. However, Vishi cautions that going this route can be expensive and it can decrease the shelf life of a medication.

"It's also important to keep in mind that clinically you may warrant a medication that contains animal products. We always have to weigh the risks versus benefits of the medications available," she said.

Clare Crossan, who blogs for The Vegan Woman, has these words of advice for vegans struggling with taking medicine that contains animal products.

"A dead vegan, or one crippled by chronic pain, isn’t much use to the animals we have pledged to help," she writes. "I feel we can be of far more use if we can stay healthy enough to continue actively campaigning for animal rights."

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