What can Viagra do? Well, it can help men suffering from erectile dysfunction have satisfying sex lives by letting blood flow and inflate their 'urges'. However, that is all Viagra may be useful for. According to a study by researchers from the University of Manchester, tests to study the drug's application to treat a growth condition in foetuses—known as Foetal Growth Restriction (FGR)—show that it affects no improvement in their condition.
Using mice to study the effects of Viagra on foetal growth, the researchers found no improvement in the growth of foetuses. However, they found that pups developed high blood pressure as they attained maturity.
Opining that evidence from the study points towards exercising caution in using Viagra to treat FGR, Mark Dilworth, co-author of the study said, "Our study suggests there may be long-term risks associated with its use in mice and importantly, there is a lack of beneficial effect in recent human clinical trials."
Known uses of Viagra
Sildenafil, commonly known as Viagra, improves blood flow and is prescribed to treat erectile dysfunction(ED) in men. It promotes increased blood flow to the penis, effectively aiding in an erection. It is also used to treat a rare but dangerous condition known as Pulmonary arterial hypertension(PAH). Due to PAH, the pulmonary arteries carrying blood to the lungs are blocked or thickened.
Viagra has proven to relax these arteries and increase blood flow to the lungs, much like how it works in the case of ED. Therefore, it is because of this property, that it has been studied for potential application in the treatment of FGR.
What is with Foetal Growth Restriction (FGR)?
FGR is a condition where the unborn foetus or baby is smaller than it has to be at a corresponding time during the gestation period. One of the primary causes for FGR is the poor functioning of the placenta, thereby affecting the flow of blood to the foetus, and essentially disrupting the transfer of nutrients from mother to baby. It affects nearly three in every 100 pregnancies.
While some of the effects of FGR are immediate, some can manifest in adulthood. For example, a higher risk of stillbirth is one of the more immediate effects of the condition. Increased risk of suffering from developmental problems, and other ailments in adulthood such as diabetes and heart disease, are some of the long term effects.
There are no effective treatments available to treat FGR. Delivering the baby before term and caring for it outside the womb is the only option available to obstetricians most of the times. "So there is still much work to do if we are to eventually find a treatment for this distressing condition," said Lewis Renshall, lead author of the study.
Mice study reveals long-term effects
The researchers administered Viagra to pregnant mice during pregnancy and studied the long-term effects on male and female offsprings. The team found that in over 90 percent of the offsprings born to mice mothers who were given Viagra during pregnancy, there was a notable increase in their blood pressure. The ranges of these values were similar to those employed in the diagnoses of high blood pressure in human beings.
This effect was found to be similar in both male and female offsprings of normally grown and growth-restricted mice. Also, female mice exhibited a minor decrease in glucose tolerance post eight weeks and experienced moderately increased weight gain.
Renshall averred that "This, and other studies have shown Sildenafil - otherwise known as Viagra - may not be a suitable treatment for FGR unless life-saving benefits can be demonstrated."
Parallel studies showed similar results
While the Manchester study was the first to report the side effects of Viagra when used for treating FGR, other parallel studies showed similar results. An international clinical trial studying the effect of Viagra in the treatment of a severe form of human FGR called STRIDER, also learnt that the drug had no remarkable benefit on prolongation of pregnancy or foetal growth.
A Dutch branch of the STRIDER study was terminated after 11 babies were born to mothers who were given the medication died of lung complications. However, the UK-Ireland and New Zealand-Australia branches did not report such deaths.
Talking about the need to study the impact of maternal medication on foetuses, Dilworth said, "We do feel, however, that it is important to continue to conduct studies which look at longer-term impacts of giving medication during pregnancy as there is surprisingly little research on this."
