All of these drugs block the same enzyme. What separates them is how precisely they do it, and what else they touch along the way.
Vardenafil is among the more selective, which shows up as fewer visual side effects.
Without prescription, plain packaging. One rhythm caution worth knowing.
These drugs target PDE5. But PDE5 belongs to a family of related enzymes scattered around the body doing other jobs, and no drug distinguishes between them perfectly.
PDE6 sits in the retina. Partial blockade produces the blue tinge and light sensitivity some men experience on sildenafil.
PDE11 sits in skeletal muscle. Partial blockade is the leading explanation for the back and limb ache associated with tadalafil.
Vardenafil is more selective for PDE5 than sildenafil, with notably less action on the retinal enzyme.
Which translates directly into fewer visual effects. If that was your problem with sildenafil, this is the specific reason to consider this molecule.
Potency is not the same as strength
Vardenafil is more potent per milligram, so the figures on the box are smaller for a comparable effect.
Comparing numbers across different molecules is meaningless. A smaller number here does not indicate a weaker product.
People switch from one to another, see a lower figure, and assume they have been short-changed. They have not.
Timing and food
Thirty minutes to an hour beforehand.
A very heavy fatty meal slows it somewhat — less than with sildenafil.
Once in twenty-four hours.
Moderate alcohol.
No grapefruit juice.
Duration is several hours. Not the extended window of tadalafil, which is worth knowing if the timing is what matters most to you.
The mechanism in full
An erection is hydraulic, triggered by the nervous system.
Arousal makes nerve endings in the erectile tissue release nitric oxide. That sets off production of a messenger molecule, which relaxes the smooth muscle wrapped around the small arteries there.
Relaxed arteries let blood in. The tissue swells and, in swelling, compresses the veins that would drain it. Blood enters faster than it leaves, and stays.
PDE5 degrades the messenger, which is how an erection resolves normaly.
Vardenafil blocks PDE5, so the messenger lasts longer and the state holds.
Which is exactly why arousal is non-negotiable. No arousal, no nitric oxide, no messenger, nothing to preserve.
Nitrates: the one hard stop
This is the single line on the page with no room for interpretation.
Glyceryl trinitrate, isosorbide mononitrate, isosorbide dinitrate, nicorandil — anything taken for angina, including the spray carried for emergencies.
Together they can drop blood pressure to a dangerous level. Not mild dizziness. Circulatory collapse.
The same applies to amyl nitrite used recreationally, sold as poppers. That combination reaches emergency departments more often than anyone admits.
If you take anything in that group, this is out. No exceptions, no gap, no half tablet.
The heart rhythm point, specific to vardenafil
This distinguishes vardenafil from the others in the class and it is worth knowing.
It has a modest effect on the electrical recovery time of the heart — what is measured as the QT interval. On its own that is not usually a problem.
It becomes one in combination with other medicines that do the same thing, because the effects add.
Certain heart rhythm medicines, including amiodarone, sotalol and quinidine
Some antipsychotics
Certain antibiotics, particulary some macrolides and quinolones
Some antifungals
A few antidepressants
A known long QT interval, or a family history of sudden unexplained death, means this molecule is not the right choice. One of the alternatives is.
Who should avoid it
Recent heart attack or stroke
Unstable angina, or chest pain on light exertion
Severe heart failure
Uncontrolled high or markedly low blood pressure
Severe liver or kidney disease
Retinitis pigmentosa
Previous sudden vision loss from optic nerve ischaemia
Known long QT interval, or a family history of sudden unexplained death
On the heart question: sex places a load on the circulation roughly comparable to briskly climbing stairs. If that provokes symptoms, the heart needs looking at first.
Possible side effects
Headache, the most common
Flushing
Nasal congestion
Indigestion
Dizziness
Back ache
Visual effects, less often than with sildenafil
Two things that need help immediately
An erection lasting more than four hours. Not something to wait out — after several hours the tissue begins to sustain permanent damage.
Sudden loss of vision or hearing, one side or both. Stop and get seen urgently.
Both rare. Both measured in hours.
What it might be pointing at
The arteries supplying erectile tissue are small, and narrowing appears there before it shows in the coronary arteries — sometimes years before.
So gradual difficulty developing over months is worth treating as a prompt to check blood pressure, blood sugar and cholesterol.
Sudden onset, confined to particular situations, with morning erections still present, points elsewhere: stress, sleep, the relationship, or a medicine recently started.
Ordering without prescription: how it works
Most people order enough to keep rather than buying around a single occasion.
Pick the strength and the pack size, put in a delivery address, confirm. Couple of minutes, any time of day, no queue and no conversation across a counter.
It goes out in plain packaging. No pharmacy name on the outside, nothing that hints at what is inside. How long delivery takes depends on where the parcel is headed.
On price it comes down to strength and pack size. Larger packs generally work out better per unit.
What you pay follows pack size and strength, shown in pounds next to the quantity options. Bigger packs come out lower per unit. A generic stays below the branded version with the same ingredient inside.
