Common side effects of Levitra 20 mg and lower doses
| Side effect | Vardenafil (N = 2,203) | Placebo (N = 1,199) |
|---|---|---|
| Headache | 15% | 4% |
| Flushing | 11% | 1% |
| Rhinitis (stuffy or runny nose) | 9% | 3% |
| Dyspepsia (indigestion) | 4% | 1% |
| Sinusitis | 3% | 1% |
| Flu syndrome | 3% | 2% |
| Dizziness | 2% | 1% |
| Increased creatine kinase | 2% | 1% |
| Nausea | 2% | 1% |
Reported by at least 2% of men and more often than on placebo, fixed and flexible dose trials of 5, 10 or 20 mg. Table 1, Zydus vardenafil prescribing information, DailyMed.
Headache, flushing, nasal congestion and indigestion topped the list in placebo-controlled trials of 5, 10 and 20 mg. Headache, flushing, dyspepsia, nausea and rhinitis also appeared to rise with dose, so men on 20 mg can expect more of them than men on 5 mg.1
Back pain came in at 2.0% on vardenafil and 1.7% on placebo. In those trials, 3.4% of men stopped vardenafil because of side effects, compared with 1.1% on placebo. The leaflet says the common ones usually go away after a few hours.1
Does Levitra lower blood pressure?
Yes, a little. A single 20 mg dose lowered lying-down blood pressure by an average maximum of 7 mmHg systolic and 8 mmHg diastolic compared with placebo, and heart rate rose by 4 beats per minute. The largest drop came 1 to 4 hours after the dose.1
For most men that change is of little consequence, the label says, but it stacks on top of blood-pressure medicines. In men whose hypertension was controlled with nifedipine, vardenafil 20 mg lowered pressure by a further 6/5 mmHg.1
Nitrates, poppers and riociguat
Never combine vardenafil with nitrates. That includes nitroglycerin tablets, sprays, ointments, pastes and patches, isosorbide dinitrate and mononitrate, and recreational 'poppers' such as amyl or butyl nitrate. Together they can make blood pressure fall suddenly to an unsafe level, with dizziness, fainting, or even a heart attack or stroke.1
In a study of 18 healthy men, 20 mg of vardenafil deepened the blood-pressure drop from sublingual nitroglycerin given 1 or 4 hours later, and raised heart rate when it was given up to 8 hours later. No added effect showed at 24 hours. Even so, the label says a safe interval has not been determined.1
Riociguat (Adempas), a treatment for pulmonary hypertension, is ruled out on the same grounds: it adds to vardenafil's blood-pressure effect.1
Alpha-blockers for the prostate or blood pressure
Alpha-blockers such as tamsulosin (Flomax), terazosin (Hytrin), doxazosin (Cardura), alfuzosin (Uroxatral), silodosin (Rapaflo) and prazosin (Minipress) also widen blood vessels. Taken with vardenafil, they can lower blood pressure enough to cause fainting in some men.1
The label's rules are to be stable on the alpha-blocker first, start vardenafil at 5 mg (2.5 mg if you also take certain CYP3A4 inhibitors), and consider a time gap between the two doses. If you already take vardenafil, a new alpha-blocker should start at its lowest dose.1
The time gap comes from studies in healthy men aged 45 to 74. After terazosin was raised to 10 mg a day, 19 of 29 men had an outlier reading, meaning a standing systolic pressure under 85 mmHg or a fall of more than 30. The arm that timed both drugs to peak together was stopped early, and outliers were more frequent that way than with doses 6 hours apart.1
Is Levitra safe with heart disease?
The first question is whether sex is safe for your heart. If your doctor has said it isn't, the label rules out vardenafil and every other ED treatment.1
Vardenafil has not been studied, and isn't recommended, in men with unstable angina, a resting systolic pressure under 90 mmHg, uncontrolled pressure above 170/110, severe heart failure, or a stroke, heart attack or life-threatening arrhythmia in the last 6 months. Men with an obstruction to blood leaving the heart, such as aortic stenosis, can be sensitive to it.1
For stable angina the label has more reassuring data. In two trials of men aged 40 to 80 with exercise-induced angina, 10 mg (41 men) and 20 mg (39 men) did not change total treadmill time or time to angina compared with placebo. On 10 mg, treadmill time averaged 433 seconds against 426 on placebo.1
QT prolongation and heart-rhythm drugs
Avoid vardenafil if you were born with long QT syndrome or take a class IA antiarrhythmic such as quinidine or procainamide, or a class III one such as amiodarone or sotalol.1
In a study of 59 healthy men, 10 mg and 80 mg of vardenafil lengthened the corrected QT interval about as much as moxifloxacin 400 mg, an antibiotic known to do so: 8 and 10 msec against 8 msec with the Fridericia correction. A later study found the effect added up when 10 mg vardenafil was taken with gatifloxacin, reaching 9 msec. The clinical impact of these changes is unknown.1
Vardenafil interactions that cap the dose
| If you take | Most vardenafil allowed |
|---|---|
| Ritonavir | 2.5 mg in 72 hours |
| Cobicistat | 2.5 mg in 72 hours |
| Indinavir, saquinavir or atazanavir | 2.5 mg in 24 hours |
| Ketoconazole or itraconazole 400 mg daily | 2.5 mg in 24 hours |
| Clarithromycin | 2.5 mg in 24 hours |
| Ketoconazole or itraconazole 200 mg daily | 5 mg in 24 hours |
| Erythromycin | 5 mg in 24 hours |
Section 2.4, Zydus vardenafil prescribing information, DailyMed.
Drugs that block the liver enzyme CYP3A4 raise vardenafil levels, sometimes many times over. Ritonavir increased exposure 49-fold, and ketoconazole 200 mg a day 10-fold. Grapefruit juice was not studied but would likely raise levels too.1
No pharmacokinetic interaction was seen with warfarin, digoxin, glyburide, ranitidine or a magnesium-aluminum antacid, and vardenafil did not change warfarin's effect on prothrombin time. Up to 20 mg it did not prolong bleeding time, alone or with aspirin. Combining vardenafil with other ED treatments hasn't been studied and isn't recommended. Standard doses without these drugs are on the Levitra dosage and price page.1
Stop and get help: vision, hearing, long erections
Stop vardenafil and get medical help if you suddenly lose vision in one or both eyes. It can be a sign of NAION, a rare loss of blood supply to the optic nerve that can leave permanent vision loss. Two observational studies found the risk roughly doubled right after PDE5 inhibitor use, though neither proves the drugs cause it. A past episode of NAION raises the chance of another.1
The same goes for a sudden drop or loss of hearing, which may come with ringing in the ears and dizziness.1
An erection lasting more than 4 hours needs treatment right away. Men with Peyronie's disease or another penile deformity, or with sickle cell anemia, multiple myeloma or leukemia, should use vardenafil with caution.1
Sources
Consultation
Reader questions, answered
Answered by Dr. Ethan Cole, MD · Urology & men's sexual health
Answers follow the U.S. vardenafil prescribing information.
Dmitri asksMy blood pressure is treated and stable. Is Levitra off limits?
No. The label's concern is uncontrolled pressure above 170/110 or a resting systolic under 90. On treatment you can expect a slightly bigger drop: in men controlled on nifedipine, 20 mg lowered pressure a further 6/5 mmHg. If another doctor adds a new blood-pressure drug later, the label asks you to tell the prescriber of your vardenafil.
Benji asksIs a headache after 20 mg a reason to stop?
Headache was the most common side effect, 15% of men in trials against 4% on placebo, and it usually fades within a few hours. Because headache appeared to rise with dose, going back to 10 mg is one option your prescriber can weigh. A headache together with sudden vision or hearing loss is different: stop and get care.
Mateus asksDoes vardenafil thin the blood like aspirin?
At doses up to 20 mg it didn't prolong bleeding time, and it didn't add to aspirin's effect on bleeding time. It also left warfarin's prothrombin time unchanged. Men with bleeding disorders or active stomach ulcers weren't studied, so for them the label asks for a careful benefit-risk decision.
General education from a clinician, not personal medical advice. Bring your own history to your own prescriber.