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Viagra is one of the most controversial and widely talked about pharmaceutical drugs to have hit the market in the last 30 years. The drug works well in most cases and has changed people’s lives for the better. In this article, we will look briefly at the history of viagra, its pros and cons, and anything to be wary of if you are considering its use.
Fast facts on viagra here are some key points about Viagra. More detail and supporting information is in the main article.
- Viagra was initially designed for hypertension and angina pectoris.
- Viagra’s main competitors are Cialis (tadalafil) and Levitra (vardenafil).
- Side effects include headaches, hearing loss, impaired vision, increased intraocular pressure and dyspepsia.
- Viagra pills are blue and diamond-shaped.
- Individuals with kidney disease should not take Viagra.
- Some athletes take Revatio in the belief that it enhances their performance.
- Viagra works by inhibiting the enzyme cGMP-specific phosphodiesterase type 5.
- Viagra was designed by Pfizer in Kent, England.
- Some people use Viagra recreationally, although it is not thought to have any benefit in people without penile dysfunction.
What is Viagra?
Viagra was initially designed to help lower blood pressure but is now typically used to treat erectile dysfunction.
Viagra is the brand name for sildenafil citrate and is used for treating erectile dysfunction and pulmonary arterial hypertension. Originally developed by scientists in Great Britain, it was brought onto the market by Pfizer Inc., a US pharmaceutical company. Viagra is also sold under brand name Revatio.
Sildenafil citrate’s chemical formula is C22H30N6O4S.
Viagra works by inhibiting an enzyme called cGMP-specific phosphodiesterase type 5, that delays degradation of cGMP, which controls blood flow in the penis.
A brief history of Viagra
Viagra has become the prime treatment for impotence (erectile dysfunction), competing with Cialis (tadalafil) and Levitra (vardenafil) for market share.
Initially, the drug was designed by Pfizer scientists working in Kent, England. They were in fact working on a drug for hypertension (high blood pressure) and angina pectoris (a symptom of ischemic heart disease).
During the phase I trials, it was noted that the drug did very little to prevent angina but did induce marked penile erections. Hitting the market in 1998, Viagra was the first oral treatment approved to treat erectile dysfunction in the US.
Viagra’s meteoric rise to fame has seen it enter usage as an illicit drug. But, Viagra use in individuals without erectile dysfunction does not seem to have any effect. Although, researchers have noted that there is a significant placebo effect. On a similar note, there is no proven benefit for women taking the drug.
With endorsements from former US Senator Bob Dole and football star Pelé, the drug goes from strength to strength. In 2008, Viagra generated some $1.93 billion of revenue for Pfizer.
Dosage
Viagra, for erectile dysfunction, comes in blue, diamond-shaped pills, in doses of 25, 50, or 100 milligrams. The patient takes a maximum of one pill in a 24-hour period, between 30 minutes to 1 hour before sexual intercourse.
Revatio, for pulmonary arterial hypertension, comes in white, round, film-coated tablets. Patients take one 20 mg Revatio tablet three times a day.
Adverse events for Viagra
According to clinical trial results, the most common side effects include headaches, nasal congestion, impaired vision, photophobia, and dyspepsia. Less commonly, some users have experienced cyanopsia (everything has a tinted blue tinge).
In very rare cases, Viagra use can lead to vision impairment and nonarteritic anterior ischemic optic pain, numbness, tingling, or weakness. সহজ বাংলা: স্নায়ুর ক্ষতি/সমস্যা।" data-rx-term="neuropathy" data-rx-definition="Neuropathy means nerve damage or irritation causing pain, numbness, tingling, or weakness. সহজ বাংলা: স্নায়ুর ক্ষতি/সমস্যা।">neuropathy. Postmarketing surveillance side effects have included (very rare) priapism, heart attack, sudden hearing loss, increased intraocular pressure, and ventricular arryhythmias. Since 2007, its labeling in the US has included a warning of the potential risk of sudden hearing loss.
Viagra can decrease blood supply to the optic nerve, causing sudden vision loss. This very rare adverse event occurred mainly to patients who had heart disease, hypertension, insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes, high cholesterol, or pre-existing eye problems. Nobody really knows whether the vision loss was caused by Viagra.
Interactions – HIV patients on protease inhibitors should discuss using Viagra with their doctors – protease inhibitors increase the likelihood and severity of side effects. Experts say such patients should have no more than 25mg, and not more often than every 48 hours.
If the patient is taking alpha blockers, they should make sure they take that medication and Viagra at least four hours apart, to prevent low blood pressure.
Contraindications – the following individuals should not take Viagra (or check with their doctors first):
- Those on nitric oxide donors, nitrates and organic nitrites
- Men who are advised to refrain from sexual intercourse because of cardiovascular risk factors
- Patients with severe hepatic impairment
- Patients with kidney disease
- Individuals with low blood pressure (hypotension)
- Those who have had a recent heart attack
- Those who have had a recent stroke
- Individuals with hereditary degenerative retinal disorders.
Cautions and interactions
As with all medications, adverse effects and interactions can occur when using vardenafil.
One in 10 men will experience a pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।" data-rx-term="headache" data-rx-definition="Headache means pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।">headache.
Other common side effects include:
- stuffy or runny nose
- stomach upset
- dizziness
- flushing
In most cases, these disappear within a few hours.
Other potentially serious symptoms include:
- ringing in the ears, or sudden hearing loss
- irregular heartbeat
- swelling in the ankles, hands, or feet
- difficulty breathing
- chest pain
The patient should stop using vardenafil if these occur.
Rarely, an allergic reaction may occur. This can lead to hives, difficulty breathing, and swelling of the face, tongue, and throat. It can lead to shock, and it can be fatal. If these symptoms appear, it should be treated as a medical emergency.
Priapism
Very rare side effects may include priapism when an erection lasts longer than 4 hours. This can damage the penis. If an erection lasts too long, the individual should seek medical attention.
Visual disturbances
Visual disturbances can happen when blood pressure drops in the eye. The individual may see a blue tinge to objects, and they may have difficulty distinguishing between the colors green and blue.
Very rarely, there may be a sudden deterioration in vision in one or both eyes. This can indicate a heart condition, an existing eye problem, high cholesterol, insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes, or hypertension.
If any sudden loss of vision occurs, the individual should stop taking the medication and seek medical help immediately.
Vision problems are most likely in patients with other conditions, such as heart or coronary artery disease, insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।" data-rx-term="diabetes" data-rx-definition="Diabetes is a condition where blood sugar stays too high because insulin is low or not working well. সহজ বাংলা: রক্তে চিনি বেশি থাকার রোগ।">diabetes, and high cholesterol. Vision problems are more likely to happen if the person smokes, or if they are aged over 50 years.
Interactions
Using vardenafil with some other drugs can lead to serious adverse effects.
Possible reactions include:
- a potentially dangerous drop in blood pressure, or hypotension
- dizziness
- fainting
There is also a risk of stroke and heart attack.
A man should not use vardenafil if he is taking nitrate drugs, such as riociguat (Adempas), or other nitrate drugs for chest pain or heart problems.
It should not be used with recreational drugs, amyl nitrate, and butyl nitrate, also known as poppers.
Other drugs that may interact include, but are not limited to:
- bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।" data-rx-term="antibiotic" data-rx-definition="An antibiotic is a medicine used to treat bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।">antibiotic and antifungal medications
- other medications for erectile dysfunction
- drugs for prostate problems, blood pressure, or heart rhythm disorders
- medications for HIV or AIDS
Grapefruit juice contains a chemical that makes adverse effects more likely, so it should not be consumed while using vardenafil.
Things to know before using vardenafil
Patients should tell their doctor about all their medical conditions and any other medications or supplements they use before taking vardenafil.
This is especially important if they have:
- a deformity in the shape of the penis, such as Peyronie’s disease
- a heart condition, such as arrhythmia, heart failure, or angina
- a family history of a rare heart condition known as long QT syndrome
- hearing problems
- hemophilia or some kind of bleeding problem
- hypotension (low blood pressure) or hypertension (high blood pressure)
- liver or kidney problems
- multiple myeloma, leukemia, sickle cell anemia, or some other kind of blood cell problem
- non-arteritic anterior ischemic optic neuropathy (NAION)
- damage to the retina of the eye
- stomach ulcers
- retinitis pigments, a rare genetic eye disease
They should also tell the doctor if they have ever experienced priapism, a seizure, or if they have recently had a stroke or a heart attack.
References
