
Viagra is the brand name name for sildenafil citrate produced by Pfizer. It is a type of phosphodiesterase type 5 (PDE5) inhibitor. It was discovered in 1989 while looking for a treatment of chest pain. Viagra is sometimes prescribed to treat sexual dysfunction in women, however, it has not been approved by the FDA for this purpose. There are currently 4 PDE5 inhibitors approved to treat erectile dysfunction, sildenafil, tadalafil, vardenafil, and avanafil. Other types of PDE5 inhibition do exist, but have not been approved for treatment.
Erectile dysfunction is an inability to achieve and sustain an erection to permit normal sexual intercourse. Erectile dysfunction is affects an estimated 5-20% of men worldwide. Erectile dysfunction often causes psychological effects, such as reduced sexual confidence and increased anxiety.
Oral PDE5 inhibitors are the first line of treatment for erectile dysfunction.
PDE5 inhibitors bind to PDE5 throughout the body and inhibit hydrolysis of cGMP, leading to hypotension and penile erection when in the presence of sexual attraction. Because PDE5 inhibition has systemic effects, it can cause side effects such as headache, flushing, upset stomach, runny nose, and changes in vision. These side effects can be worse if Viagra is mixed with alcohol.
Viagra starts working after 30 minutes and keeps working for 4-6 hours, with a maximum duration of 12 hours. A meta analysis from 2015 determined that Viagra works better than other PDE5 inhibitors, but causes more side effects.
Viagra is available over the counter in the United Kingdom.
Currently, a prescription is required to purchase Viagra in Australia. Some people attempt to circumvent this rule by purchasing black market Viagra. This can be risky, as black market drugs are often counterfeits and do not contain the same ingredients. Viagra is considered the most generic drug in the world. Counterfeit Viagra pills have been found to contain unapproved types of PDE5 inhibitors, arsenic, pesticides, and even lead paint to give the signature blue color.
Even if the pill itself is not dangerous, it may not contain enough active ingredient to effectively treat erectile dysfunction. It is important to purchase prescription medications only from trusted pharmacies.
Viagra can be dangerous to people who have heart problems.
A person who intends to take Viagra should talk to their doctors first to make sure the Viagra will not cause dangerous hypotension or interact with their blood pressure medications. Viagra should never be taken with nitric oxide.
There are many websites online that claim to sell authentic Viagra without a prescription.
If you are going to buy a prescription drug online, please talk to your doctor first and make sure it will not put you at risk. Some websites have a doctor available to answer questions and require a prescription before you can place your order. These types of websites are more trustworthy than others. If you have any suspicions about your medication, do not take it. If you have side effects that interfere with daily activities, go see a doctor. Only a doctor can help you decide if Viagra is safe for you to take.

Medical Practitioner (General Practice) with postgraduate diplomas in Cape Town. My special interest is erectile dysfunction.