ED medications can cause side effects, and it’s crucial to have access to a medical provider if needed. However, because sexual stimulation is required to initiate the local penile release of nitric oxide, tadalafil’s inhibition of PDE5 will have no effect without sexual stimulation. The drug works by increasing blood flow to the penis, thus aiding in achieving an erection. And not all online pharmacies have the capability to safely ship medications that need to be temperature-controlled, such as insulin. The generic versions are just as effective and much less expensive. What Are the Symptoms of Erectile Dysfunction? Often, these are prescribed for chest pain called angina.For the as-needed dose, plan to take Cialis at least 30 minutes before sexual activity, but bear in mind it may take as long as 2 hours to take effect. Also, Cialis requires sexual stimulation to. Depending on your symptoms and needs, you may be prescribed Viagra, sildenafil, Cialis, tadalafil, Stendra, paroxetine, or a combination of tadalafil and sildenafil, available as mints or pills. Prices range from $3 to $ per dose or $82 to $ for a monthly supply, depending on the medication. Cialis lasts up to 36 hours in the body, while Viagra lasts 4–6 hours in the body. Both are taken 30 minutes before sex. Cialis can cause limb pain, while Viagra can cause vision change, rash.