People are being warned of the dangers of sourcing prescription medicines online as there can be no guarantees about their safety.

The warning was issued by the Health Products Regulatory Authority (HPRA), which has just published details of all of the illegal medicinal products it detained in 2016.

Last year, it detained almost 674,000 dosage units of falsified or other illegal medicines - that is around 1,800 dosage units detained every day.

According to the figures, 40% of the illegal products that were detained were sedatives, 16% were anabolic steroids and 14% were medicines for erectile dysfunction.

The HPRA noted that while last year's figure was lower than 2015's figures of 1.1 million detained units, there was a big increase in the number of anabolic steroids detained in 2016 (109,006 compared to 38,049 in 2015).

"It remains a serious concern that people are sourcing medicines from unknown and potentially untrustworthy sources. There is absolutely no guarantee that they contain the type or quantity of active substance they say that they do. In some cases they can contain different substances altogether and they can be very dangerous to human health. We emphasise that, while some sites may appear legitimate, they are, too often, a front for illegal activity," commented John Lynch of the HPRA.

He expressed particular concern about the jump in detentions related to anabolic steroids and pointed out that the misuse of these drugs has been linked to a range of major side-effects including blood clots, headaches, depression, irritability and stomach pain.

"People are sourcing these products for purposes of performance enhancement and are either unaware of or ignoring the significant dangers posed by these prescription medicines in the absence of medical supervision. As always, we urge people to seek advice from their healthcare professional if they have any concerns about their health," Mr Lynch said.

The HPRA is responsible for prosecuting cases where it considers that there is a significant risk to public health. Last year, six prosecution cases were initiated and 13 voluntary formal cautions were issued. The prosecutions related to the supply of anabolic steroids, slimming medicines and erectile dysfunction medicines.

The HPRA works in partnership with the Gardai and Revenue's Customs Service, as well as other regulatory and law enforcement agencies worldwide, to tackle the illegal manufacture, importation and distribution of health products such as medicines, medical devices and cosmetic products.

For more information on the dangers of buying prescription medicines online, click here