Key takeaways
Sildenafil (Viagra) and tadalafil (Cialis) are both medications used to treat erectile dysfunction (ED). They belong to the same drug class, PDE-5 inhibitors, but there are some differences between them. Tadalafil is also FDA-approved to treat benign prostatic hyperplasia (BPH), while sildenafil is also approved to treat pulmonary arterial hypertension. Sildenafil is typically taken as needed, about an hour before sexual activity, and its effects last up to 8 hours. In contrast, tadalafil can be taken either as needed or daily, with effects lasting up to 36 hours, offering more flexibility for spontaneous activity. Both medications are available as lower-cost generics. Common side effects for sildenafil include headaches and flushing, while tadalafil may cause headaches and indigestion. Both medications can interact with heart and blood pressure medications, leading to dangerously low blood pressure, so it's important to discuss all medications with your healthcare provider before starting either one.
