Showing posts with label viagra. Show all posts
Showing posts with label viagra. Show all posts

Tuesday, May 29, 2007

Side Effects of Viagra

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Less common

Abnormal vision, including blurred vision, seeing shades of colors differently than before, or sensitivity to light; bladder pain; burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings; burning feeling in chest or stomach; cloudy or bloody urine; dizziness; increased frequency of urination; indigestion; pain on urination; stomach upset; tenderness in stomach area

Rare

Bleeding of the eye; convulsions (seizures); decreased vision or other changes in vision; double vision; prolonged, painful, or inappropriate erection of penis; redness, burning, or swelling of the eye; vision loss, temporary

Note: The following rare side effects have not been completely established as being caused by sildenafil

Blood sugar problems (more likely with patients with diabetes mellitus), such as anxiety, behavior change similar to drunkenness, blurred vision, cold sweats, confusion, cool and pale skin, difficulty in concentrating, drowsiness, excessive hunger, fast heartbeat, headache, nausea, nervousness, nightmares, restless sleep, shakiness, slurred speech, and unusual tiredness or weakness; bone pain; breast enlargement; chest pain; chills; confusion; convulsions (seizures); coughing up blood; deafness; decrease in amount of urine or in frequency of urination; dizziness or lightheadedness, especially when getting up from a lying or sitting position; dry eyes; dry mouth; dryness, redness, scaling, or peeling of the skin; eye pain; fainting or faintness; fast, irregular, or pounding heartbeat; feeling of something in the eye; groups of skin lesions with swelling; headache (severe or continuing); heart failure; hives; increase in size of pupil; increased sweating; increased thirst; itching of skin; low blood pressure; lower back or side pain; migraine headache; nausea (severe or continuing); nervousness; numbness of hands; painful, swollen joints; redness, itching, or tearing of eyes; shortness of breath or troubled breathing; skin paleness; skin rash; skin ulcers; sore throat and fever or chills; sudden weakness; swelling of face, hands, feet, or lower legs; twitching of muscles; unusual tiredness or weakness; unusual feeling of burning or stinging of skin

Incidence not known

Blindness

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Aches or pains in muscles; bloody nose; diarrhea; difficult or labored breathing; flushing; headache; nasal congestion; pain or tenderness around eyes and cheekbones; redness of skin; sneezing; stomach discomfort following meals; stuffy or runny nose; trouble in sleeping; unusually warm skin

Rare

Anxiety

Note: The following rare side effects have not been completely established as being caused by sildenafil

Abdominal pain; abnormal dreams; clumsiness or unsteadiness; cough; diarrhea or stomach cramps (severe or continuing); difficulty in swallowing; ear pain; increased amount of saliva; increased skin sensitivity; lack of coordination; loss of bladder control; mental depression; nausea; numbness or tingling of hands, legs, or feet; rectal bleeding; redness or irritation of the tongue; redness, soreness, swelling, or bleeding of gums; ringing or buzzing in ears; sensation of motion, usually whirling, either of one's self or of one's surroundings; sexual problems in men (continuing), including failure to experience a sexual orgasm; sleepiness; sores in mouth and on lips; tense muscles; tightness of chest or wheezing; trembling and shaking; vomiting; waking to urinate at night; worsening of asthma

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Precautions While Using Viagra

Sildenafil has not been studied with other medicines used for treatment of erectile dysfunction. Presently, using them together is not recommended .

It is important that you tell all of your healthcare providers that you take sildenafil . If you need emergency medical care for a heart problem, it is important that your healthcare provider knows when you last took sildenafil.

Use sildenafil exactly as directed by your doctor . Do not use more of it and do not use it more often than your doctor ordered. If too much is used, the chance of side effects is increased.

If you experience a prolonged or painful erection for 4 hours or more, contact your doctor immediately. This condition may require prompt medical treatment to prevent tissue damage of the penis and possible permanent impotence.

This medicine does not protect you against sexually transmitted diseases. Use protective measures and ask your doctor if you have any questions about this.

It is important to tell your doctor about any heart problems you may have now or may have had in the past. This medicine can cause serious side effects in patients with heart problems.

If you experience sudden loss of vision in one or both eyes, stop using sildenafil and contact your doctor immediately.

Proper Use of viagra

Special patient directions come with sildenafil. Read the directions carefully before using the medicine .

This medicine usually begins to work within 30 minutes after taking it for erectile dysfunction. It continues to work for up to 4 hours, although its action is usually less after 2 hours.

Dosing—The dose of sildenafil will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of sildenafil. If your dose is different, do not change it unless your doctor tells you to do so.
For oral dosage form (tablets):
For treatment of erectile dysfunction:
Adults up to 65 years of age—50 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. If needed, your doctor may increase your daily dose to 100 mg or decrease your daily dose to 25 mg.
Adults 65 years of age and older—25 mg as a single dose no more than once a day, 1 hour before sexual intercourse. Alternatively, the medicine may be taken 30 minutes to 4 hours before sexual intercourse. If needed, your doctor may increase your daily dose.
If you are taking protease inhibitors, such as for the treatment of HIV, your doctor may recommend a 25 mg dose and may limit you to a maximum single dose of 25 mg of Viagra in a 48 hour period
For treatment of pulmonary arterial hypertension:
Adults—20 mg three times per day. Each dose should be taken about 4 to 6 hours apart and can be taken with or without food.
Children—Use and dose must be determined by your doctor.

Storage—To store this medicine:
Keep out of the reach of children.
Store away from heat and direct light.
Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
Keep the medicine from freezing. Do not refrigerate.
Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Before Using viagra

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For sildenafil, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to sildenafil. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Sildenafil is not indicated for use in women. Sildenafil has not been studied in pregnant women. However, sildenafil has not been shown to cause birth defects or other problems in animal studies.

Breast-feeding—It is not known whether sildenafil passes into breast milk. Sildenafil is not indicated for use in women for erectile dysfunction. Mothers who are taking this medicine for pulmonary arterial hypertension and who wish to breast-feed should discuss this with their doctor.

Older adults—Elderly people are especially sensitive to the effects of sildenafil, which may increase their chance of having side effects. Patients 65 years of age and older who are taking this medicine for erectile dysfunction are started on a low dose, 25 mg, of sildenafil. Patients who are taking this medicine for pulmonary arterial hypertension may also need to be started at a lower dose. The dose may be increased by a doctor as needed and tolerated.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking sildenafil, it is especially important that your health care professional know if you are taking any of the following:
Alpha-blockers (medicine for high blood pressure—Sildenafil when taken together with an alpha-blocker medicine may cause very low blood pressure. Sildenafil doses above 25 mg should not be taken within 4 hours of taking an alpha-blocker medicine.
Bosentan (e.g., Tracleer)—May increase amounts of bosentan in the body
Cimetidine (e.g., Tagamet)
Erythromycin (e.g., E.E.S. or Ery-Tab)
Itraconazole (e.g., Sporanox)
Ketaconazole (e.g., Nizoral)
Mibefradil (e.g., Posicor)
Ritonavir (e.g., Norvir)
Saquinavir (e.g., Fortovase or Invirase)—These medicines may increase the unwanted effects of sildenafil, unless lower starting doses of sildenafil are used
Erectile dysfunction medicines—These medicines should not be used at the same time as sildenafil because the safety of using these medicines in combination has not been proven.
Nitrates, such as nitroglycerin (e.g., Nitrostat or Transderm-Nitro)—Sildenafil increases the lowering of blood pressure by nitrates too much and their use together is not recommended

Other medical problems—The presence of other medical problems may affect the use of sildenafil. Make sure you tell your doctor if you have any other medical problems, especially:
Age greater than 50 years or
Coronary artery disease or
Diabetes or
Hyperlipidemia (excess of lipids in the blood) or
Hypertension (high blood pressure) or
Low cup to disc ratio (“crowded disc”) or
Smoking—These conditions may increase risk for a serious eye problem called NAION.
Arrhythmias (irregular heartbeat) or
Coronary artery disease or
Heart attack, history of (within the last 6 months) or
High blood pressure or
Low blood pressure or
Stroke, history of (within the last 6 months)—Chance of problems occurring may be increased
Abnormal penis, including curved penis and birth defects of the penis—Chance of problems occurring may be increased
Bleeding problems or
Retinitis pigmentosa—Chance of problems occurring may be increased. It is not known if the medicine is safe for use in these patients
Conditions causing thickened blood or slower blood flow, including leukemia; multiple myeloma (tumors of the bone marrow); or polycythemia, sickle cell disease, and thrombocythemia (blood problems) or
Priapism (history of)—Although sildenafil does not cause priapism (erection lasting longer than 6 hours), patients with these conditions have an increased risk of priapism and it could occur while using sildenafil
Heart or blood disease—Sexual activity increases the heart rate and blood flow and can increase the chance of problems occurring for some patients who use any type of medicine, including sildenafil, that increases sexual ability
Kidney problems (severe) or
Liver problems (severe)—Chance of problems occurring may be increased. Lower starting doses may be used and doses increased as needed and as tolerated
NAION (serious eye condition) in one or both eyes, previously—May increase your chance of getting NAION again.
Pulmonary veno-occlusive disease (high blood pressure in the blood vessels of the lungs)—May make heart problems worse in patients with this serious condition

Description viagra

Sildenafil (sil-DEN-a-fil) belongs to a group of medicines that delay the enzymes called phosphodiesterases from working too quickly. The penis is one of the areas where these enzymes work. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence).

By controlling the enzyme phosphodiesterase, sildenafil helps to maintain an erection that is produced when the penis is stroked. Without physical action to the penis, such as that occurring during sexual intercourse, sildenafil will not work to cause an erection.

Sildenafil is also used to treat the symptoms of pulmonary arterial hypertension. This is the high blood pressure that occurs in the main artery that carries blood from the right side of the heart (the ventricle) to the lungs. When the smaller blood vessels in the lungs become more resistant to blood flow, the right ventricle must work harder to pump enough blood through the lungs. Sildenafil helps by increasing the supply of blood to the lungs and reducing the workload of the heart.

This medicine is available only with your doctor's prescription, in the following dosage form(s):
Oral
Tablets (U.S.)

How should you take Viagra?

Taking Viagra approximately 1 hour before sexual activity works best for most men. Depending on how and when the drug works for you, an interval of one-half hour to as much as 4 hours may prove ideal.

--If you miss a dose...

Viagra is not for regular use. Take it only before sexual activity.

--Storage instructions...

Store at room temperature.

Why should Viagra not be prescribed?

Do not take Viagra if you are taking any nitrate-based drug, including nitroglycerin patches (Nitro-Dur, Transderm-Nitro), nitroglycerin ointment (Nitro-Bid, Nitrol), nitroglycerin pills (Nitro-Bid, Nitrostat), and isosorbide pills (Dilatrate-SR, Isordil, Sorbitrate). Combining Viagra with these drugs can cause a severe drop in blood pressure.

If Viagra gives you an allergic reaction, do not use it again.

Recommended dosage

Doses range from 25 milligrams to 100 milligrams, depending on the drug's effect. The usual dose is 50 milligrams. If you are over 65, have liver or kidney problems, or are taking erythromycin, ketoconazole, itraconazole, ritonavir, or saquinavir a dose of 25 milligrams may be sufficient. Your doctor will adjust the dosage if the drug is not working properly for you.

Take Viagra only before sexual activity. The manufacturer recommends a maximum of 1 dose per day (1 dose every 2 days for those taking ritonavir).

To avoid low blood pressure, do not take the 50-milligram or 100-milligram dose of Viagra within 4 hours of taking an alpha-blocking drug such as Cardura.

Possible food and drug interactions when taking Viagra

If Viagra is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Viagra with the following:

Other impotence remedies including Caverject and Muse
Alpha-blockers such as doxazosin (Cardura)
Amlodipine (Norvasc)
Cimetidine (Tagamet)
Erythromycin (E-Mycin, Ery-Tab, PCE)
Itraconazole (Sporanox)
Ketoconazole (Nizoral)
Nitrates such as Isordil, Nitro-Bid, and Nitro-Dur
Rifampin (Rifadin, Rimactane)
Ritonavir (Norvir)
Saquinavir (Fortovase, Invirase)

Special warnings about Viagra

If you have heart problems severe enough to make sexual activity a danger, you should avoid using Viagra. Use it cautiously--if at all--if you've had a heart attack, stroke, or life-threatening heart irregularities within the past 6 months. Be equally cautious if you have severe high or low blood pressure, heart failure, or unstable angina (crushing heart pain that occurs at any time).

If you take Viagra and develop cardiac symptoms (for example, dizziness, nausea, and chest pain) during sexual activity, do not continue. Alert your doctor to the problem as soon as possible.

If you have a condition that might result in long-lasting erections, such as sickle cell anemia, multiple myeloma (a disease of the bone marrow), or leukemia, use Viagra with caution. Also use cautiously if you have a genital problem or deformity such as Peyronie's disease. If an erection lasts more than 4 hours, seek treatment immediately. Permanent damage and impotence could result.

If you have a bleeding disorder, a stomach ulcer, or the inherited eye condition known as retinitis pigmentosa, use Viagra with caution. Its safety under these circumstances has not yet been studied.

To avoid low blood pressure, do not take the 50-milligram or 100-milligram dose of Viagra within 4 hours of taking an alpha-blocking drug such as Cardura.

Remember that Viagra offers no protection from transmission of sexually transmitted diseases, such as HIV, the virus that causes AIDS.

Viagra Description

VIAGRA®, an oral therapy for erectile dysfunction, is the citrate salt of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).

Sildenafil citrate is designated chemically as 1 - [[3 - (6,7 - dihydro - 1 - methyl - 7 - oxo - 3 - propyl - 1H - pyrazolo[4,3 - d]pyrimidin - 5 - yl) - 4 - ethoxyphenyl]sulfonyl] - 4 - methylpiperazine citrate.

Sildenafil citrate is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7. VIAGRA (sildenafil citrate) is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and 100 mg of sildenafil for oral administration. In addition to the active ingredient, sildenafil citrate, each tablet contains the following inactive ingredients: microcrystalline cellulose, anhydrous dibasic calcium phosphate, croscarmellose sodium, magnesium stearate, hypromellose, titanium dioxide, lactose, triacetin, and FD & C Blue #2 aluminum lake.

What other drugs will affect sildenafil?

Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems, including nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, Minitran, Deponit, Transderm-Nitro), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket), or recreational drugs such as amyl nitrate or nitrite ("poppers").

Before taking sildenafil, tell your doctor if you are using any of the following medications:

bosentan (Tracleer);

cimetidine (Tagamet, Tagamet HB);

an antibiotic such as erythromycin (E-Mycin, Eryc, Ery-Tab) or clarithromycin (Biaxin);

doxazosin (Cardura), prazosin (Minipress), Terazosin (Hytrin);

HIV medicines such as amprenavir (Agenerase), tipranavir (Aptivus), darunavir (Prezista), efavirenz (Sustiva), nevirapine (Viramune), indinavir (Crixivan), saquinavir (Invirase, Fortovase), lopinavir/ritonavir (Kaletra), fosamprenavir (Lexiva), ritonavir (Norvir), atazanavir (Reyataz), or nelfinavir (Viracept);

an antifungal medication such as itraconazole (Sporanox) or ketoconazole (Nizoral);

carbamazepine (Tegretol), phenobarbital (Luminal), or phenytoin (Dilantin); or

rifampin (Rifadin, Rimactane) or rifabutin (Mycobutin).

If you are using any of these drugs, you may not be able to take sildenafil, or you may need dosage adjustments or special tests during treatment.

There may be other drugs not listed that can affect sildenafil. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

What are the possible side effects of sildenafil?

If you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during sexual activity, stop and call your doctor right away. You could be having a serious side effect of sildenafil. Stop using sildenafil and get emergency medical help if you have sudden vision loss. Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using sildenafil and call your doctor at once if you have any of these serious side effects:

chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;

irregular heartbeat;

swelling in your hands, ankles, or feet;

shortness of breath;

vision changes;

feeling light-headed, fainting; or
penis erection that is painful or lasts 4 hours or longer.

Continue taking sildenafil and talk with your doctor if you have any of these less serious side effects:

warmth or redness in your face, neck, or chest;

stuffy nose;

headache;

upset stomach; or

back pain.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.

What should I avoid while taking sildenafil?

Avoid drinking alcohol, which can increase some of the side effects of sildenafil. Avoid using other medicines to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others), without first talking to your doctor.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine. Symptoms of a sildenafil overdose may include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.

What happens if I miss a dose?

Viagra is used as needed, so you are not likely to miss a dose.

If you miss a dose of Revatio, take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the medicine at the next regularly scheduled time. Do not take extra medicine to make up the missed dose.

How should I take sildenafil?

Take sildenafil exactly as it was prescribed for you. Do not take it in larger doses or for longer than recommended by your doctor.

Revatio is usually taken three times each day, about 4 to 6 hours apart.

Viagra is usually taken only when needed, 30 minutes to 1 hour before sexual activity. You may take it up to 4 hours before sexual activity. Do not take Viagra more than once per day.

Viagra can help you have an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor's instructions.

If you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during sexual activity, stop and call your doctor right away. You could be having a serious side effect of sildenafil.
Store this medication at room temperature away from moisture and heat.

What should I discuss with my healthcare provider before taking sildenafil?

Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with a nitrate medicine can cause a serious decrease in blood pressure, leading to fainting, stroke, or heart attack.

A small number of patients have had a sudden loss of eyesight after taking sildenafil. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether sildenafil is the actual cause of such vision loss. Sudden vision loss with sildenafil use has occurred most often in people with heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoke or are over 50 years old.

Before taking sildenafil, tell your doctor if you have:

heart disease or heart rhythm problems;

a recent history (in the past 6 months) of a heart attack, stroke, or heart rhythm disorder;

congestive heart failure;

high or low blood pressure;

coronary artery disease;

liver disease;

kidney disease;

a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;

a bleeding disorder such as hemophilia;

a stomach ulcer;

retinitis pigmentosa (an inherited condition of the eye);

a physical deformity of the penis (such as Peyronie's disease); or

if you have been told you should not have sexual intercourse for health reasons.

If you have any of these conditions, you may not be able to use sildenafil or you may need a dosage adjustment or special tests during treatment.
FDA pregnancy category B: This medication is not expected to be harmful to an unborn baby. Do not use sildenafil without telling your doctor if you are pregnant or plan to become pregnant during treatment. It is not known if sildenafil passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

What is sildenafil?

Sildenafil relaxes muscles and increases blood flow to particular areas of the body.

Sildenafil under the name Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.

Sildenafil may also be used for purposes other than those listed here.

What is the most important information I should know about sildenafil?

Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with a nitrate medicine can cause a serious decrease in blood pressure, leading to fainting, stroke, or heart attack. If you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during sexual activity, stop and call your doctor right away. You could be having a serious side effect of sildenafil. Do not take sildenafil more than once a day. Allow 24 hours to pass between doses. Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis.

A small number of patients have had a sudden loss of eyesight after taking sildenafil. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether sildenafil is the actual cause of such vision loss. Sudden vision loss with sildenafil use has occurred most often in people with heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoke or are over 50 years old.
Stop using sildenafil and get emergency medical help if you have sudden vision loss.