Medically reviewed by: Thomas Fischer (Pharmacist). This article has been written according to strict guidelines and medical standards.
Medically reviewed by: Thomas Fischer (Pharmacist)
Viagra came on the scene in 1998 and has changed the life of many men. Despite being on the market and used by millions of men, not everyone understands how the medication works. To understand this, we need to know about the active ingredient that makes Viagra work.
What Does Sildenafil Treat?
Sildenafil is a medication that is effective in the treatment of impotence, otherwise known as erectile dysfunction. The generic name of the drug is Sildenafil, and the brand name is Viagra. There are a few other applications for Sildenafil.
Pulmonary arterial hypertension (PAH) is a condition where the arteries that go from your heart to your lungs experience high blood pressure. This is different from the high blood pressure we are familiar with. It is essential to know that Revatio and Viagra are not interchangeable.
Vasospasm is a condition where an artery can spasm, which limits the blood flow and oxygen and will lead to tissue death. It most often affects the brain or the heart. Strokes, Atherosclerosis, and Raynaud’s Phenomenon are conditions where vasospasms happen most often.
Secondary Raynaud’s Phenomenon occurs when blood flow and oxygen restriction and tissue damage or death happen on extremities, usually fingers and toes. Some causes of secondary Raynaud’s Phenomenon are Lupus, scleroderma, rheumatoid arthritis, Sjogren’s syndrome, arterial diseases, smoking, carpal tunnel syndrome, and injuries to the hands or feet.
Sildenafil has been found to improve quality of life and exercise tolerance in patients with systolic heart failure and secondary pulmonary hypertension. Secondary Pulmonary Hypertension develops as a result of other conditions such as emphysema, COPD, blood clots, lupus, scleroderma, HIV, congenital heart disorders, some diet drugs, and liver diseases.
Some athletes have used Sildenafil to improve their workouts without using steroids. They hope that the increased blood flow that Sildenafil brings will help them build up their bodies faster. However, more studies need to be done.
What Other Ingredients Are in Sildenafil?
In addition to the active ingredient, Sildenafil citrate, each tablet contains other components that make up the pill. These are called inactive ingredients, ones that don’t make the active ingredient work, but they help in the manufacture and appearance of the tablet in different ways.
These are the ingredients found in each Sildenafil tablet:
- Anhydrous Dibasic Calcium Phosphate – These bind ingredients together in capsules and compressed tablets
- Croscarmellose Sodium – This helps the medication to be absorbed in the gastrointestinal tract
- FD & C Blue #2 Aluminum Lake – “FD&C” shows that the color is approved to be used in medication, cosmetics, and food. The dye in pills helps to or show dosage strength and helps distinguish from other medicines.
- Hypromellose – Helps to release the medication in a controlled manner
- Lactose - Lactose is easy to compress and used in many pharmaceutical medications
- Magnesium Stearate – Keeps ingredients from sticking together and helps control the quality and consistency of the pill.
- Microcrystalline Cellulose - Very often used in vitamins and pills, this is made from refined wood pulp. It is commonly used as an anti-caking agent and an additive to increase the size of the tablet but keeping the function of Sildenafil intact.
- Titanium Dioxide – A coloring for pharmaceutical syrups, tablets, and capsules
- Triacetin – Works to keep the active ingredient in a medication stabilized and lengthens the shelf life
Definition and Uses For Sildenafil
Sildenafil is used to treat erectile dysfunction in men (also called sexual impotence). Sildenafil is in a group of medications called PDE5 inhibitors. The drug works by slowing down the reaction between the PDE5 (phosphodiesterase type 5) and the cGMP (Cyclic guanosine monophosphate).
Other Uses of Sildenafil
Sildenafil is used for other medical applications and is being studied as future treatments:
- Exercise Tolerance - For those with heart conditions it can help them exercise better with less stress on their heart.
- Pulmonary Arterial Hypertension – Sildenafil is also in a medication called Revatio. It is used to treat PAH. In this case Viagra is not interchangeable with Viagra or generic Sildenafil.
Future studies:
- Antiviral – Sildenafil is being explored as a medication to help COVID-19 suffers
- Cancer – Low doses are being studied as an antitumor drug
- Hair Growth – Sildenafil shows some potential in the treatment of alopecia
- Multiple Sclerosis – Sildenafil may help to suppress inflammation and allow some myelin regeneration
- Skin Flap Survival – Skin flaps are used in surgical reconstruction. They need oxygen to survive, and Sildenafil is being examined to see if it can be combined with another medication to improve skin survival and healing.
How Does Sildenafil Work?
To understand how Sildenafil works, we need to understand some body chemical activity. PDE5 is an enzyme that is found in tissues of the body, mostly within the eyes, penis, and the cardiovascular system. Enzymes are proteins that help to make chemical reactions within the body. PDE5 causes a chemical reaction with cGMP.
In the role of treating erectile dysfunction, cGMP relaxes muscles and increases the size of blood vessels and blood flow to them. When a man takes Sildenafil, it prevents PDE5 from working too fast and enhances the effects of Sildenafil. This helps the penis to achieve and maintain an erection.
How is Sildenafil Dosed and Taken?
To treat erectile dysfunction, the usual initial dose of Sildenafil is 50 mg by mouth once a day on an as-needed basis. It should be taken one hour before sexual activity. Depending on how the medication works for you, the maintenance dosage will be between 25 to 100 mg.
Communicate with your physician about your symptoms to see what dosage works best for you. Dosages of Sildenafil for off-label treatments are different from that of erectile dysfunction. Do not adjust the dosage without consulting your doctor.
Side Effects, Interactions, and Contraindications
All medications come with some side effects. The most often experienced side effects are listed below and can dissipate. Tell your doctor if any become severe or don’t go away:
- Acid reflux
- Back pain
- Diarrhea
- Flushing
- Insomnia - difficulty falling or staying asleep
- Lightheadedness
- Mild Headache
- Muscle pain
- Nosebleeds
- Runny or stuffy nose
- Tingling or numbness in the extremities (legs, feet, arms, or hands)
- Upset stomach
Serious Side Effects of Sildenafil
Get medical help right away if you experience any of the symptoms in the Warning section and the following:
- Irregular heartbeat
- Itching or burning sensation with urination
- Lightheadedness
- Painful erection (or one that lasts longer than four hours)
- Ringing in your ears or sudden hearing loss
- Seizures
- Shortness of breath
- Signs of an allergic reaction – difficulty breathing, hives, inflammation of the tongue, throat feels like it is closing, swollen lips and face
- Sudden changes in vision – blurring or loss of eyesight
- Swelling - Puffiness especially in your ankles, feet, or hands
- Symptoms of a heart attack – sudden onset of pain that radiates from the chest to your jaw or shoulder, sweating and nausea at the same time
Interactions
It is important to tell your doctor about all prescriptions, over the counter medications, recreational (including illegal ones), and herbal or nutritional supplements while using Sildenafil. There can be some severe interactions between Sildenafil and the following drugs:
- Acid Reducer- Cimetidine
- Alcohol - This can make Sildenafil less effective
- Alpha blockers - Uroxatral, Cardura, Minipress, Flomax, Jalyn, Norvasc, Amturnide, Tekamlo
- Antibiotics - E.E.S., E-Mycin, Erythrocin, Mycobutin, Rifadin, Rimactane, Rifamate, Rifater
- Antifungals - Onmel, Sporanox, Nizoral
- Barbiturates - Butapap, Fioricet, Fiorinal, Butalbital, Seconal
- Beta-blockers - Tenormin, Tenoretic, Trandate, Lopressor, Toprol XL, Dutoprol, Corgard, Corzide, Hemangeol, Inderal LA, InnoPran, Tracleer
- Blood Thinners - Coumadin, Jantoven
- Grapefruit - The fruit or the juice should not be consumed
- HIV Treatments - Reyataz, Evotaz, Prezista, Prezcobix, Lexiva, Crixivan, Kaletra, Viracept, Norvir, Kaletra, Invirase, Aptivus, Viramune, Atripla, Sustiva
- Medications for high blood pressure
- Other erectile dysfunction devices or medications
- Seizure medication - Carbatrol, Epitol, Tegretol, Carbamazepine, Phenobarbital, Dilantin, Phenytek
- St. John’s Wort
Contraindications of Sildenafil
People who suffer from the following medical conditions should not use Sildenafil. Check with your physician if you have any of the following:
- Bent penis with erection
- Chronic heart failure
- Fibrous tissue formation in the penis
- Hearing loss
- Recent heart attack
- Hereditary retinal dystrophy
- Hypertrophic cardiomyopathy
- Leukemia
- Life-threatening irregular heart rhythm
- Liver problems
- Low blood pressure
- Multiple myeloma
- Narrowing of the aortic heart valve
- Peyronie's disease
- Pigmentary retinopathy
- Problems with food passing through the esophagus
- Pulmonary veno-occlusive disease
- Severe insufficiency of the autonomic nervous system
- Severe renal impairment
- Sickle cell anemia
- Significant uncontrolled high blood pressure
- Stroke
- Sudden vision loss due to loss of the blood supply to the front of the optic nerve
- Sudden worsening of angina
Is a Prescription For Sildenafil Required in the US?
In the United States, both brand name Viagra and generic Sildenafil are only available by prescription from a licensed physician.
Even if you feel embarrassed about the situation, it is important to talk about erectile dysfunction. It can cause significant stress and confidence issues and affect personal relationships. It may turn out that another condition or different medical treatments can reverse erectile dysfunction.
If you think you have erectile dysfunction, schedule an appointment to speak with your primary care physician. Discuss with your doctor and ask if your situation fits with suffering erectile dysfunction and if Sildenafil could work for you.
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