After she admitted swallowing 30 packs of opium, a 51-year-old woman was brought to a hospital emergency room in Tehran, the New England Journal of Medicine reported yesterday. When a CT scan confirmed the presence of several small oval objects in her abdomen, the doctors gave her laxatives. She passed a collection of small, sausage-like opium packs “without complication,” report doctors Nasim Zamani and Hossein Hassanian-Moghaddam.

One of those packs was sent for lab analysis, and results came back confirming opium and also the presence of lead—a lot of lead. Luckily for this particular patient, she didn’t seem to be showing any symptoms of lead poisoning, but she appears to have gotten off lightly. Over the past few years, the problem of lead-contaminated opium has become increasingly urgent in Iran, which is used as a major pathway for opium trafficking from Afghanistan.

In early 2016, write Zamani and Hassanian-Moghaddam in a CDC report, another patient case report found blood lead levels 14 times higher than normal. The patient in question didn’t have any obvious exposure to lead but was known to use oral opium. That prompted tracking of another 800 patients over the next few months, whose blood lead levels ranged from about five times higher than normal to 1,100 times higher. These blood lead levels were substantially higher than earlier reports of lead poisoning in opium users.

A more recent analysis of 249 patients with a history of opium dependency found a narrower but still alarming range of elevated blood levels, as well as common symptoms of lead poisoning like abdominal pain and nausea. It’s not clear just how much lead an opium user might be ingesting or inhaling, write Zamani and Hassanian-Moghaddam, but they calculate that it could be considerably higher than the levels that caused a “cluster of heavy-metal poisoning among Ayurvedic medication users” in the US.

It’s also not clear how the lead ends up in opium. Opium poppies grown in lead-contaminated soil have been found to accumulate lead, and Afghanistan’s poppy-growing regions overlap to a large extent with its lead mines, note Mohammad Mahdi Hayatbakhsh and his colleagues in their study of opium users’ lead levels. It’s possible that the process of producing opium from poppy seed pods also introduces lead contamination.

The lead could also be added intentionally at some point to increase the weight (and therefore the sale value) of the final product.

With the high level of opium use in Iran, lead poisoning from opium is a problem in its own right: a World Health Organization report estimates that more than 250,000 people in Iran are at risk of lead poisoning through opium.

In the US, the majority of opium comes through South America and Mexico, and the problem has not yet been reported in opium-derived products like heroin; there are only a few reports of lead-laced heroin from the 1980s. But some opium grown in Afghanistan does make its way to the US, and it makes up the majority of the opium market in Russia, Asia, and Europe. The risk, suggests the WHO, "highlights a need for better monitoring of illegal drug supplies."

The New England Journal of Medicine, 2018. DOI: 10.1056/NEJMicm1807901 (About DOIs).