All three medications belong to the same drug family, called PDE5 inhibitors, and they all work by the same mechanism. So why does it matter which one you take? Because they differ on the practical questions: how long until it works, how long it lasts, whether you can have a meal first, how often you want to take it, and what it costs.
Here is the side by side first, then the detail.
The Comparison Table
| Property | Sildenafil (Viagra) | Tadalafil (Cialis) | Vardenafil (Levitra) |
|---|---|---|---|
| Onset | 30 to 60 min | 30 to 60 min | 30 to 60 min |
| Duration | 4 to 5 hours | Up to 36 hours | 4 to 5 hours |
| Common doses | 25, 50, 100 mg | 5, 10, 20 mg (also low daily dose 2.5 to 5 mg) | 5, 10, 20 mg |
| Effect of food | Slowed by fatty meals | Not affected | Slowed by fatty meals |
| Common side effects | Headache, flushing, blocked nose, indigestion, blue tint to vision (rare) | Headache, back pain, muscle aches, flushing, indigestion | Headache, flushing, indigestion |
| Best for | Planned, occasional use; cost conscious patients | Spontaneity, weekend use, or daily low dose | Men who do not tolerate sildenafil well |
| SA availability | Wide. Many generics | Wide. Many generics | Available but fewer brands |
| Typical cost (generic, per dose) | Lowest | Mid range | Mid range |
Sildenafil In Detail
Sildenafil is the original. It launched as Viagra in 1998 and changed the field. Today, generic sildenafil is widely available in South Africa, registered with SAHPRA, and substantially cheaper than branded Viagra.
What it is good at
- Reliable, well studied, predictable
- Cheap as a generic
- Effective for planned sex (take an hour beforehand)
Where it is less ideal
- Short window of action means you need to plan
- Heavy meals reduce and slow the effect significantly
- Slightly more visual side effects than the others, including a rare bluish tint to vision
Practical dosing
Most men start at 50 mg. The doctor adjusts up to 100 mg or down to 25 mg based on response and side effects. Taken on an empty or light stomach, around an hour before sex. Once a day at most.
Tadalafil In Detail
Tadalafil is the long acting one. It earned the nickname 'the weekend pill' because a single dose covers a Friday night through to Sunday morning. For many men this changes the whole experience because they stop having to think about it.
What it is good at
- Long duration means spontaneity
- Not affected by food
- Available as a low daily dose (2.5 to 5 mg) for men who prefer continuous coverage
- Has a secondary use in benign prostatic hyperplasia, which is convenient if you have both
Where it is less ideal
- Slightly more likely to cause back pain or muscle aches than the others
- Costs a bit more than sildenafil as a generic
- Side effects, if you get them, last longer because the drug lasts longer
Practical dosing
Two patterns. On demand, 10 or 20 mg taken at least 30 minutes before sex, repeated no more than once every 72 hours. Or daily, at a low dose (usually 5 mg), which keeps a constant low level in your system and removes the need to plan altogether.
Not Sure Which One Is For You
An online consultation looks at your medical history, lifestyle, and what you want from the medication, then picks the right starting option.
Start ConsultationVardenafil In Detail
Vardenafil is the underrated middle option. Pharmacologically very similar to sildenafil, but slightly more selective in its mechanism, which can mean fewer side effects in some men. Not as widely prescribed in SA as the other two, but a useful alternative.
What it is good at
- Some men who get bad headaches on sildenafil tolerate vardenafil better
- Quick onset
Where it is less ideal
- Short window of action like sildenafil
- Also affected by fatty meals
- Fewer generic brands available locally
How Doctors Usually Choose
The decision is usually quick and based on a small number of factors:
- How often do you want to be ready? Daily or near daily, low dose tadalafil. Once or twice a week, on demand sildenafil or tadalafil. Less than once a week, sildenafil is usually the cheapest fit.
- Do you eat large meals before sex? Tadalafil is more forgiving.
- Are you cost sensitive? Sildenafil generic.
- Do you also have BPH (prostate enlargement)? Daily tadalafil treats both.
- Did you have side effects on one of them? Switch to one of the others. Tolerance varies between men.
What They All Share
All three need sexual stimulation to work. None of them increases desire. All three are prescription medicines in South Africa under SAHPRA. All three must not be used with nitrate medicines (used for angina), and all three should be used with care in men on alpha blockers or with certain heart conditions. See the side effects and safety page for the full list.
Related Reading
Frequently Asked
They are roughly equivalent at clinically appropriate doses. Effectiveness depends more on the right dose for the right individual than on the choice between the three.
Tadalafil, by a wide margin. Up to 36 hours, compared to four to five hours for sildenafil and vardenafil. This is the main reason tadalafil is often preferred.
Light to moderate drinking is generally fine. Heavy drinking reduces effectiveness and increases side effects (flushing, headache, dizziness). It is also a common cause of treatment 'failure'.
Sildenafil and vardenafil are slowed by a heavy fatty meal. Tadalafil is largely unaffected by food. If you have just had a steak and chips, sildenafil will take longer to work.
Generic sildenafil is generally the cheapest at SEP pricing. Generic tadalafil is somewhat more expensive but still affordable. Vardenafil tends to sit between the two.