Tadalafil and vardenafil are prescription medications used to treat erectile dysfunction (ED). Both belong to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors, which function by improving blood flow to the penis. While they are similar in their purpose and classification, they possess distinct properties that make them suitable for different needs and circumstances.
Mechanism of Action
Both tadalafil and vardenafil function by targeting phosphodiesterase type 5 (PDE5), an enzyme found in the smooth muscle cells of blood vessels. Achieving an erection is a process that begins with sexual stimulation, which triggers the release of nitric oxide in the penis. This release activates another enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP). The primary role of cGMP is to relax the smooth muscles, causing the blood vessels that supply the penis to widen and fill with blood.
The PDE5 enzyme’s job is to break down cGMP, which allows the blood vessels to return to their normal size and the erection to subside. Tadalafil and vardenafil work by blocking the action of this PDE5 enzyme. By inhibiting PDE5, these medications allow cGMP to remain active for a longer period, which helps sustain blood flow and maintain an erection when a man is sexually aroused.
Key Differences in Usage and Timing
A primary distinction between tadalafil and vardenafil lies in how long their effects last. Tadalafil is known for its extended duration of action, remaining effective for up to 36 hours after a single dose. This prolonged window has earned it the nickname “the weekend pill” because it allows for greater spontaneity. In contrast, vardenafil has a much shorter duration, with its effects lasting for about 4 to 5 hours.
These medications also offer different dosing strategies. Vardenafil is taken on an as-needed basis, about 60 minutes before sexual activity. Tadalafil can also be taken as needed, but it uniquely offers a low-dose daily option. This daily regimen, 2.5mg or 5mg, allows the drug to remain at a constant level in the body, providing readiness for sexual activity at any time without the need for pre-planning.
The onset time, or how quickly the drugs begin to work, also varies slightly. Vardenafil takes effect within 30 to 60 minutes. Tadalafil can start working in as little as 30 to 45 minutes when taken as needed. Another practical difference involves their interaction with food. The absorption of vardenafil can be delayed and its effectiveness reduced if taken with a high-fat meal, while tadalafil’s absorption is not significantly impacted by food.
Comparing Side Effects and Drug Interactions
While effective, both medications can cause side effects, many of which overlap due to their shared mechanism of action. Common side effects for both tadalafil and vardenafil include headache, facial flushing, nasal congestion, and indigestion. These reactions are mild to moderate and often subside as the body adjusts to the medication.
Some side effects are more characteristically associated with one drug over the other. For instance, back pain and muscle aches are more frequently reported by users of tadalafil. Vardenafil, on the other hand, has been linked in some cases to changes in color vision.
Both drugs have potential interactions with other medications. Both tadalafil and vardenafil are strictly contraindicated with nitrates, a class of drugs prescribed for chest pain (angina). Combining them with nitrates can cause a sudden and dangerous drop in blood pressure. Caution is also advised when these medications are taken with alpha-blockers, which are used to treat high blood pressure and prostate issues, as this combination can also lead to low blood pressure. Taking vardenafil and tadalafil together is not recommended as it increases the risk of adverse effects.
Making an Informed Choice
Choosing between tadalafil and vardenafil often comes down to personal lifestyle and preference. The choice may be influenced by tadalafil’s extended duration for spontaneity versus vardenafil’s shorter action for planned activity. The daily tadalafil option also offers a constant state of readiness that some may find more convenient.
Other health factors can influence the decision. Tadalafil is also approved for treating the signs and symptoms of benign prostatic hyperplasia (BPH), a common condition in older men involving an enlarged prostate. For men experiencing both ED and BPH, tadalafil could address both conditions with a single medication.
The choice is a medical one that requires a thorough discussion with a healthcare provider. A doctor can assess an individual’s complete medical history, including any cardiovascular conditions or other medications being taken, to determine which option is the most suitable and safe.