Counterfeit phosphodiesterase type 5 inhibitors pose significant safety risks

4 min


There is a growing problem in counterfeit medications around the world, particularly in developing countries.

Phosphodiesterase type 5 inhibitors (PDE5is), oral treatments for erectile dysfunction (ED), are contributing to the rapid growth of this market due to the popularity with men with ED of obtaining medication over the internet.

There are various reasons for this including the high cost of the drugs and the sensitivity around the problem of ED.

A recent article in the New England Journal of Medicine highlighted the dangers of counterfeit medication, reporting an outbreak of hypoglycaemia (including 4 deaths) in Singapore traced to contamination of counterfeit ED medications with a powerful diabetes drug.

Moreover, counterfeiters are becoming increasingly sophisticated and the drugs they produce more difficult to distinguish from their genuine counterparts.


To document the extent of the problem and the dangers associated with counterfeit ED medications.


The authors reviewed the literature concerning counterfeit medication, particularly PED5is, using multiple sources including published articles, government and organisational websites and legal journals.


Millions of counterfeit PDE5is are seized yearly and account for the bulk of all counterfeit pharmaceutical product seizures. It has been estimated that up to 2.5 million men in Europe could be exposed to illicit sildenafil (a particular PDE5i), suggesting that there may be as many illegal as legal users of sildenafil.

Analysis of the contents of counterfeit PDE5is shows inconsistent doses of active pharmaceutical ingredients (from 0% to > 200% of labelled dose), contaminants (including talcum powder, commercial paint and printer ink) and alternative ingredients that are potentially hazardous.

In one analysis, only 10.1% of samples were within 10% of the labelled tablet strength.

Estimates place the proportion of counterfeit medications sold over the Internet from 44% to 90%. Of men who purchase prescription-only medication for ED without a prescription, 67% do so using the Internet.

Counterfeit PDE5is pose direct risks to health, including serious illness or death, accidental overdose, drug-drug interactions and incorrect or no guidance regarding contraindications.

There are also indirect risks associated with bypassing the medical system. A study showed that more than 30% of men reported no healthcare interaction when purchasing ED medications.

Because > 65% actually had ED, these men missed an opportunity for evaluation of comorbidities (e.g. diabetes and hypertension).


Globally, increased obstacles for counterfeiters are necessary to combat pharmaceutical counterfeiting, including fines and penalties. The worldwide nature of the counterfeit problem requires proper coordination between countries to ensure adequate enforcement.

Physicians who treat ED need to inform patients of the dangers of ordering PDE5is via the Internet.

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