Drug Uses

Viagra is used in the treatment of erectile dysfunction. Viagra helps the flow of blood into the male organ and maintains erection while performing sexual activities.
Cialis helps men to achieve and sustain an erection for longer periods while having sexual activities. It is an oral medication.
Benefits of Cialis: When compared to Viagra and Levitra, Cialis’ effects last longer (upto 48 hours). Cialis also has fewer side effects.
Cialis is meant for daily use so that you can be prepared anytime.
Levitra helps men to have stronger erections during sexual activities. It dilates the blood vessels of the penis thereby helping more blood to flow into it. This leads to a stronger erection.

Usage

Viagra is generally taken 30 minutes to 1 hour before sexual activity. Viagra can also be taken 4 hours before sexual activity. The dosage should not increase more than once in a day (24 hours).
You must always follow your doctor’s dosage instructions while taking Cialis. If you still have any doubts then there will be detailed dosage instructions on the medicine label.
Cialis comes in various doses like 5mg, 10mg and 20 mg. The ideal dose for starting with Cialis is 10mg once a day. You need to take it half an hour before sexual activity.

You may choose to take Levitra with a meal or without one.

The drug works best when taken 30 to 60 minutes before initiating sexual activity.

The dosage should not increase more than once in a day (24 hours).

Drug Class and Mechanism

Viagra helps to treat impotence in men. It is a phosphodiesterase type 5 inhibitor. Viagra helps increase the blood flow into the penis thereby maintaining an erection during sexual activities.
Cialis is a phosphodiesterase inhibitor type 5. It works by helping the blood flow into a penis to achieve and maintain an erection.

Levitra is a phosphodiesterase inhibitor that works by helping blood flow into a penis to achieve and maintain an erection.

Missed Dose


Since Viagra is an erectile dysfunction drug, it must only be used when required. So, there are no chances of a missed dose since it is not taken according to a regular dosage schedule.

You need to take Cialis only before any sexual activity. You cannot take Cialis more than one dose a day.

Since Levitra is an erectile dysfunction drug, it must only be used when required. So, there are no chances of a missed dose since it is not taken according to a regular dosage schedule.
Never take two doses at one time.

Storage

Store Viagra at room temperature between 59 and 86 degrees F (15-30 degrees C). Protect it from direct exposure to light, heat and moisture. Keep away from children and pets.
Store Cialis at room temperature.
Store Levitra at room temperature.

Safety Information

If you are using any of the following mention it to your doctor befor using Viagra:
bosentan (Tracleer);
* a blood thinner such as warfarin (Coumadin);
* 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).

Discuss your past/current medical history in detail with your doctor before beginning treatment with any new medication. If you are using any herbal supplements or over the counter medication, including vitamin pills, then mention it to your doctor. Also tell your doctor if you are using the following:
(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 like amyl nitrate or nitrite ("poppers").
Do not use Viagra if you have ever had an allergic reaction to it or if you have heart problems severe enough to make sexual activity dangerous. If you had a heart attack, stroke, or life-threatening heart irregularities within the past 6 months use it cautiously. Also be cautious in case you have severe high or low blood pressure, heart failure or unstable angina.
In case you have cardiac symptoms like dizziness, nausea, and chest pain during sex do not take Viagra.
In conditions like sickle cell anemia, multiple myeloma (a disease of the bone marrow), or leukemia where you might have long lasting erection use Viagra with caution. In case of genital problem or deformity such as Peyronie's disease use Viagra cautiously. If erection lasts for more than 4 hours, seek help immediately as it might lead to permanent sexual disorders.
If you are suffering from conditions like bleeding disorder, a stomach ulcer, or the inherited eye condition known as retinitis pigmentosa use Viagra with caution.
For Cialis:
Discuss your past/current medical history in detail with your doctor before beginning treatment with any new medication. If you are using any herbal supplements or over the counter medication, including vitamin pills, then mention it to your doctor.
Please mention to your doctor if you have suffered from or are suffering from medical conditions like using a nitrate drug for chest pain or heart problems.
Doctors advise against using the drug if you are allergic to any ingredient in it or 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),
isosorbide mononitrate (Imdur, ISMO, Monoket), or recreational drugs such as amyl nitrate or nitrite ("poppers").

Cialis when taken with a nitrate medicine can cause a serious decrease in blood pressure, leading to fainting, stroke or heart attack. Tell your doctor if you have any of the following conditions before taking tadalafil:
a recent history a heart attack (within the past 90 days);
a recent history of stroke or congestive heart failure (within the past 6 months);
angina (chest pain);
high or low blood pressure;
liver disease;
kidney disease (or if you are on dialysis);
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.
For Levitra:
Doctors advise against using the drug if you are allergic to any ingredient in it or if you are taking medications containing nitrates, alpha–blockers.
Also do not take it if you are taking or using nitroglycerin (eg, tablet, patch, ointment), nitrates (eg, isosorbide), or certain antiarrhythmics (eg, amiodarone, quinidine);you have had a heart attack, stroke, or life-threatening irregular heartbeat within the past 6 months; you have certain eye problems (eg, retina diseases such as retinitis pigmentosa), uncontrolled chest pain, uncontrolled high blood pressure, low blood pressure, irregular heartbeat (eg, congenital QT prolongation), severe heart failure, severe liver problems, or end-stage kidney disease that requires dialysis.