Cialis works by preventing the action of a chemical in the body called phosphodiesterase type-5. This helps relax the blood vessels and keep them dilated for longer.

What is Cialis?

  • Cialis (tadalafil) relaxes muscles and increases blood flow to particular areas of the body.
  • Cialis is used to treat erectile dysfunction (impotence) in men. Cialis is also used to treat the signs and symptoms of benign prostatic hyperplasia (BPH), a condition in which the prostate gland becomes enlarged.

Before taking Cialis

Do not take Cialis if you are allergic to tadalafil.

Cialis should not be used together with nitrate medication, such as nitroglycerin (Nitrolingual, and others), isosorbide dinitrate, isosorbide mononitrate (Imdur), or recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking Cialis with a nitrate medicine for chest pain or heart problems can cause a sudden and serious decrease in blood pressure.

If you have any of these other conditions, you may need a Cialis dose adjustment or special tests:

Cialis can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people taking Cialis, most of whom also had 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.

It is not clear whether Cialis is the actual cause of vision loss. Stop using Cialis and get emergency medical help if you have sudden vision loss.

How to take Cialis

Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack. Take cialis exactly as your doctor has told you.
It is not important whether you take cialis before, with or after food.

If you have been prescribed cialis for erectile dysfunction:

  • Take your medicine at least 30 minutes before sexual activity.
  • Cialis should not be taken more frequently than once a day.

If you have been prescribed cialis for pulmonary arterial hypertension:

  • Try to take cialis at the same time each day to avoid missing any doses.
  • If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a missed dose.

How should I take Cialis?

  • Take Cialis exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
  • Cialis can be taken with or without food. Do not break or split a Cialis tablet. Swallow it whole.
  • Cialis is usually taken only once per day. Follow your doctor's instructions. For erectile dysfunction, take the medicine just before sexual activity but not more than once per day.
  • Cialis can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor's instructions.
  • Do not take Cialis for erectile dysfunction if you are taking Adcirca for pulmonary arterial hypertension.
  • Do not take Cialis more than once a day. Allow 24 hours to pass between doses. If you take the medication daily, take it at the same time each day. 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.

What should I avoid while taking Cialis?

  • Drinking alcohol can increase certain side effects of Cialis.
  • Grapefruit and grapefruit juice may interact with Cialis and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.
  • Avoid using other medicines to treat erectile dysfunction, such as sildenafil (Viagra) or vardenafil (Levitra) while you are taking Cialis.

Cialis side effects

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

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

  • changes in vision or sudden vision loss;
  • ringing in your ears, or sudden hearing loss;
  • chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
  • irregular heartbeat;
  • shortness of breath, swelling in your hands or feet;
  • seizure (convulsions);
  • feeling light-headed, fainting; or
  • penis erection that is painful or lasts 4 hours or longer.

Less serious Cialis side effects may include:

This is not a complete list of side effects and others may occur. 

What other drugs will affect Cialis?

Before taking Cialis, tell your doctor about all other medicines you use, especially:

  • rifabutin, rifampin, or rifapentine;
  • an antibiotic such as clarithromycin, erythromycin, or telithromycin;
  • antifungal medication such as itraconazole (Sporanox), ketoconazole (Nizoral), miconazole, or voriconazole;
  • an antidepressant such as nefazodone;
  • a barbiturate such as phenobarbital;
  • drugs to treat high blood pressure or a prostate disorder, such as alfuzosin, doxazosin (Cardura), prazosin, terazosin (Hytrin), tamsulosin;
  • heart or blood pressure medication such as diltiazem, nicardipine, quinidine, or verapamil;
  • HIV or AIDS medications such as darunavir, efavirenz, etravirine, nevirapine, fosamprenavir, indinavir, ritonavir, and others; or
  • seizure medications such as carbamazepine (Tegretol), phenytoin, and others.

This list is not complete and other drugs may interact with Cialis.

How to store Cialis

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

If you have any more questions please ask your Pharmacist.

Remember to keep all medicines out of reach of children

Please Note: We have made every effort to ensure that the content of this information sheet is correct at time of publish, but remember that information about drugs may change. This sheet does not list all the uses and side-effects associated with this drug. For full details please see the drug information leaflet which comes with your medicine. Your doctor will assess your medical circumstances and draw your attention to any information or side-effects which may be relevant in your particular case.

References:

http://www.patient.co.uk/medicine/tadalafil

http://www.cialis.com/Pages/home.aspx

http://en.wikipedia.org/wiki/Tadalafil

http://www.drugs.com/cialis.html

http://www.rxlist.com/cialis-tadalafil/drug.htm

http://www.rxlist.com/cialis-drug.htm