Drugs Log

Researchers have warned about “herbal remedies” for erectile dysfunction sold over-the-counter in Hong Kong after most of them were found to contain untested variants of well-known anti-impotence drugs.

These variants, or “analogues,” are copies of controlled drugs but they are slightly modified in their chemical structure to escape patent and other drug-related laws.

Cranked out illegally, these chemicals are not tested for their efficacy or safety and can have unpredictable, adverse effects. They are added undeclared into “health products,” which do not come under stringent tests in most countries.

Writing in the latest issue of the Hong Kong Medical Journal, the scientists said they studied 26 anti-impotence products sold in convenience stores and pharmacies.

Although their packaging declared that they contained only “herbal ingredients,” variants of sildenafil and vardenafil were found in 14 of them. Sildenafil was found in one product.

Sildenafil and vardenafil are generic names for their better known trade labels Viagra and Levitra, respectively, and they are prescribed drugs in Hong Kong.

“The positive rate of concealed drug analogues in male erectile dysfunction health products is alarmingly high. Such analogues are difficult to detect by ordinary laboratory methods and might be used in an attempt to evade regulatory inspection,” wrote the researchers at the Hospital Authority Toxicology Reference Laboratory in the journal’s October issue.

“Without going through the stringent drug testing process, the adverse effects of these chemicals remain largely unknown and unpredictable,” they warned, as they called for urgent and more effective surveillance and control.

“The medical profession and the public should be alerted to this under-recognized threat.”

This malpractice came to light when a previously healthy 28-year-old man got admitted to hospital for an unsteady gait and frequent falls — signs of ataxia.

Doctors then learnt that he had taken an anti-impotence “health product” for over a week before showing those symptoms.

Classified as phosphodiesterase-5 inhibitors, sildenafil and vardenafil are known to have side-effects like nausea, headache, facial flushing and visual disturbances. Serious cardiovascular effects have also been reported.

But ataxia has never been linked to this class of drugs.

“Unlike the parent pharmaceutical, no formal studies have been performed to assure the safety and efficacy of these analogues,” the researchers wrote.

“Evidently, the adverse effects of drug analogues are highly unpredictable and the consumption of such products is dangerous.”

Analogues have also been found in so called “natural” or “herbal” slimming products in Hong Kong and at least one woman has died of a cardiac arrest after consuming them.

What are herbal remedies in short:

Herbal medicine, sometimes referred to as Herbalism, Botanical medicine or Herbology, is the use of plants, in a wide variety of forms, for their therapeutic value. Herb plants produce and contain a variety of chemical compounds that act upon the body and are used to prevent or treat disease or promote health and well-being.

A brief history of herbal medicine.

Humans, and even Neanderthals, have used plants to treat their ailments for at least tens of thousands of years; most likely even longer than that.

The first written accounts of the use of herbs originate in China, although all other civilisations from the ancient world were using plants as natural remedies for their ailments. Western herbal medicine dates back to ancient Greece and its famous doctors like Hippocrates and Galen.

The 15th to 17th centuries were the most popular time for herbalism in Europe. Herbal remedies are still relatively popular today, mainly due to the fact that they are regarded as harmless because they are natural.

The theory of how they work.

As herbal treatments have been around for so long, and in so many cultures, there are numerous ways that they are believed to work. Many explanations lie in the mystical thinking of ancient cultures. Some believe that the appearance of the plant gives an indication of what it can be used to treat; this physical resemblance between the plant and the body part to be cured is known as the “‘Doctrine of Signatures”; a heart shaped plant would be used to treat heart problems, for example.

From the middle ages on, many practitioners have tried to classify herbal remedies by observation of their effects. This is closer to the modern scientific approach of gathering evidence.

Eastern herbal medicine still adheres to the mystical approach in its theories whilst western herbalists tend to use herbs for the ingredients they contain; mixing and matching them in the way that conventional medicine does with modern drugs.

The three main branches of herbal medicine are:
The Western herbal tradition based on Greek, Roman and medieval sources;
The Ayurvedic tradition of India;
Chinese herbal medicine.

Remedies are produced by either taking the whole plant, or just the part of the plant required, and often mixing it with other plants. They are usually boiled in water or alcohol, and made into: herbal teas; herbal decoctions; herbal syrup; herbal tincture; infused oils; salves & ointment/creams.

Scientific evidence and herbal medicine

There is a lot of mysticism behind it. The approach involves: “balancing” the body’s vital energy; the belief that it can treat anything; it is holistic, which is the reason given why no two practitioners will prescribe the same treatment for exactly the same condition in the same person; and they insist that it is natural and therefore safe.

There is no doubt that herbs contain chemical compounds, often many thousands, many of which have a physiological effect on the body. In fact up to 25% of modern medicines are based on plant origins: Aspirin; Quinine; and Digitalis, for example, are well known.

A substance that has a physiological effect on the body is by definition: a drug. Therefore those herbal remedies that have an effect, do so because of the drugs that they contain; and drugs can be beneficial or harmful. Although some very useful drugs are obtained from plant sources, it should be noted that some of the most deadly poisons are also obtained from plants: the alkaloid poisons for example.

There is some scientific evidence to support some herbal remedies. The evidence is not strongly in favour of the remedies that do show up positive results, although it does show up the need for more quality research.