Tadalafil

Tadalafil is the longest-acting PDE-5 inhibitor and known under the brand name Cialis. Like sildenafil it is used for erectile function; the big difference is duration: a single window lasts up to 36 hours.

Hence the nickname "weekend pill": you do not have to time dosing tightly to the moment. Tadalafil can be taken on demand or as a low daily dose.

The mechanism is the same as sildenafil: tadalafil blocks the enzyme PDE-5, so the vessel-relaxing messenger in the penis lasts longer and the erection comes more easily. Here too: it amplifies the natural response but does not replace arousal.

The key is the long half-life of about 17.5 hours. That gives the broad window and the option to dose tadalafil low daily, so it is simply "there" continuously.

Two ways are common:

• On demand: 10 or 20mg as needed. Thanks to the long window you do not have to time it tightly.
• Daily: 2.5 or 5mg every day. Then you are covered continuously, without thinking about dosing before the moment.

Tadalafil is less sensitive to fatty food than sildenafil. At most once a day.

The most common question in this area. The difference is mainly timing:

• Tadalafil lasts up to 36 hours, can be dosed low daily and is more robust against food. Ideal for spontaneity.
• Sildenafil lasts about 4 to 6 hours, fast onset, classically taken shortly before, but reacts more sensitively to fatty food.

In short: tadalafil for a long, relaxed window, sildenafil for the single, planned occasion. Both work through the same mechanism.

Tadalafil is very solidly evidenced. An integrated analysis of five controlled studies (Brock, 2002) showed clear improvements in erectile function and documented the response window of up to 36 hours. A later analysis (Porst, 2014) additionally confirmed the efficacy of the low daily dose (2.5 and 5mg).

The studies with links are in the source block below.

The most common effects are mild: headache, indigestion (dyspepsia), facial flush, stuffy nose. Typical for tadalafil are occasional back or muscle aches that usually pass after a day or two. All dose-dependent.

As with all PDE-5 inhibitors, the most important point: never combine with nitrates. That covers heart nitrates (e.g. nitroglycerin) and "poppers" (amyl nitrite). The combination can crash blood pressure dangerously, and because tadalafil acts for so long, that risk exists over an especially long window.

Caution also with alpha-blockers and existing cardiovascular disease. With pre-existing conditions or other medication, clear it with a doctor first.

Store the tablets dry, at room temperature and protected from light, out of reach of children. Keep the original packaging closed and mind the expiry date.