Viagra is the marketed name for Sildenafil citrate, and is the first of the new category of drugs to assist the penis in achieving and sustaining an erection. The tablet should be taken once a day. Taken half an hour before its required use, the effects last approximately 4 hours, provided adequate sexual stimulation is also provided.

• What should I know about sildenafil?
• What does the drug do?
• What should I tell my doctor if I intend to take sildenafil?
• How must I take the drug?
• What if I miss a dose?
• What if I take more than the recommended dose?
• What are the potential side-effects of the drug?
• What other drugs will affect sildenafil?
• Where can I get more information?

What should I know about sildenafil?

Do not take the tablets if you have been prescribed a nitrate drug for chest pain or heart problems. Nitrates include nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, Minitran, Deponit, Transderm-Nitro, 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").

If you maintain an erection for more than four hours, seek emergency advice straight away. A prolonged erection can cause permanent harm to your penis. Do not engage in any more sex until the symptoms have gone and seek further medical advice if you experience (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw) when having sex.
Do not take this drug more than once a day.

What does the drug do?

It relaxes the muscles within the penis. This allows more blood to pass into your penis, thereby allowing an erection to be achieved and sustained.
It is used to treat ED (erectile dysfunction).
It can also be used to treat other conditions.

What should I tell my doctor if I intend to take sildenafil?

Before taking the drug, tell your doctor if you have:

• had a heart attack, stroke, or seriously irregular heartbeats within the last six months;
• a history of heart failure;
• coronary artery disease;
• angina;
• high or low blood pressure;
• liver problems;
• kidney problems;
• ever had blood problems, including sickle cell anemia or leukemia;
• a bleeding disorder;
• a stomach ulcer;
• retinitis pigmentosa (an inherited condition of the eye);
• a physical deformity of the penis such as Peyronie's disease;
• a condition that could lead to prolonged and painful erections, such as a tumor of the bone marrow, sickle cell anemia, or leukemia; or been taking another medicine to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, and others).

Y our doctor or healthcare advisor may tell you not to take sildenafil, or you may require an adjustment of the dose, if you have any of these conditions.
The drug is not intended for and should not be taken by women. However, it is listed under the FDA’s pregnancy category B. In other words it should not harm an unborn foetus, but it is unknown if the drug passes into milk in the breast during pregnancy.
The over-65s are more susceptible to side-effects and you may be advised to take a lower dosage of the drug.

How must I take the drug?

Take it precisely as directed. If you do not understand these directions, ask your healthcare advisor to help you understand them.
Take each pill or part of the pill with a glass-full of water.
The drug is taken when required. Take it between 1½ and 4 hours before sex. If sexually stimulated, the drug can assist in achieving and maintaining an erection.
If you take the drug after a high-fat meal (such as a burger and fries), the medicine can take longer to have an effect.
Do NOT take the drug more than once a day.

Some fruit juices can produce potentially harmful side-effects and discuss these with your healthcare advisor. Fort example, do not change your drinking habits of grapefruit juice before seeking medical advice.
Store the drug at normal room temperature, out of the damp or hot conditions.

What if I miss a dose?

The drug is used as required, so you will not miss a dose.

What if I take more than the recommended dose?

Get emergency medical attention.
The symptoms of an overdose of this drug are not clearly known, but may well lead to chest pain, dizziness, an irregular heartbeat, and swelling of the ankles or legs.

What are the potential side-effects of the drug?

Stop taking the drug and get emergency medical advice if you have any of the following:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives);
• chest pain or an irregular heartbeat;
• swelling of the ankles or legs;
• shortness of breath;
• prolonged or severe dizziness;
• a prolonged (more than 4 hours) or painful erection; or
• dizziness, nausea, or angina (pain, tightness, discomfort, numbness, or tingling in the chest, arms, neck, or jaw).

Some other, less serious, side effects might be experienced. In that case, keep taking the right dose of the drug and discuss with your healthcare advisor any of the following:

• flushing;
• mild dizziness;
• headache;
• nasal congestion;
• diarrhea;
• temporary abnormalities in vision; or
• itching or a rash.

You may experience other side-effects. Discuss them with your healthcare advisor if they trouble or concern you.

What other drugs will affect sildenafil?

Before using the drug, tell your healthcare advisor if you are taking any of the following medicines:

• any other drug used to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others);
  
• the antibiotic drugs clarithromycin (Biaxin), erythromycin (E-Mycin, Eryc, Ery-Tab, others), or troleandomycin (TAO);
  
• an antifungal medication such as itraconazole (Sporanox) or ketoconazole (Nizoral);
  
• the HIV medications amprenavir (Agenerase), delavirdine (Rescriptor), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir), or saquinavir (Fortovase, Invirase);
  
• cimetidine (Tagamet, Tagamet HB);
  
• phenobarbital (Luminal);
  
• carbamazepine (Tegretol) or phenytoin (Dilantin); or
  
• rifampin (Rifadin, Rifamate) or rifabutin (Mycobutin).
  If you have been prescribed any of the medication listed above, you might be advised against taking sildenafil, or may need to adjust the dose or arrange monitoring while you take it.
  Other medicines may also react with sildenafil. Talk to your healthcare advisor before taking any other medication, including herbal products.
  

  Where can I get more information?

  Your healthcare advisor will have more information about the drug for you to discuss with him or her.
  
  

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  Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
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