CARACAS—With hospital shelves bare and the government stumped on how to settle $5 billion in arrears to pharmaceutical companies, cash-strapped Venezuela recently offered some foreign suppliers alternative compensation: diamonds, gold and coltan, the rare metal used to make cellphones and Playstations.

The proposed exchange perplexed the pharma representatives, whose companies had no policies on accepting precious gems and metals as payment, according to three people familiar with the meeting last month where Venezuela’s health minister made the offer.