Sudden vision or hearing loss with ED pills: the label warnings

In short: the ED pills in the PDE5 inhibitor class, which include sildenafil (Viagra) and tadalafil (Cialis), carry two warnings that have nothing to do with erections: sudden loss of vision and sudden loss of hearing. Both are rare, and the labels say neither has been proven to be caused by the drugs. Both labels still tell men the same thing: if either happens, stop taking these pills and get medical attention (Viagra prescribing information; Cialis prescribing information, DailyMed). This page explains what the warnings mean, how they differ from the common, harmless color tint, and what to do.

What are the vision and hearing warnings on ED pills?

The Viagra label lists them in sections 5.3 (effects on the eye) and 5.4 (hearing loss), and the Cialis label in sections 5.4 and 5.5. Both tell doctors to advise men to stop use of all PDE5 inhibitors and seek medical attention for a sudden loss of vision in one or both eyes, and to stop and seek prompt medical attention for a sudden decrease or loss of hearing (Viagra; Cialis prescribing information, DailyMed). The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists vision or hearing loss after taking oral ED medicines among the side effects that need a call to a health care professional right away (NIDDK, Treatment for ED).

Sources: Viagra and Cialis prescribing information, DailyMed. The warning is written for the whole class, so it applies whichever pill a man was using.

What is NAION?

NAION stands for non-arteritic anterior ischemic optic neuropathy: damage to the optic nerve, the cable that carries signals from the eye to the brain, thought to be caused by poor blood flow to the front of that nerve. The ED labels call it “a rare condition and a cause of decreased vision, including permanent loss of vision” (Cialis prescribing information, DailyMed). It is the most common cause of optic nerve swelling and optic nerve damage in adults over 50, and the risk factors most strongly tied to it include high blood pressure, high cholesterol, diabetes and heart and blood vessel disease (Kaur and Margolin, StatPearls).

NAION happens in men who have never taken an ED pill. The labels put its usual rate at 2.5 to 11.8 cases per 100,000 men aged 50 and over each year, and note that most, but not all, of the men in post-approval reports of NAION with a PDE5 inhibitor already had risk factors: a “crowded” optic disc (what the labels call a low cup-to-disc ratio), age over 50, diabetes, high blood pressure, coronary artery disease, high cholesterol or smoking. They add that other risk factors, such as a crowded disc, may have contributed to NAION in the studies (Viagra prescribing information, DailyMed). Several of those, including diabetes, high blood pressure and smoking-related heart and blood vessel disease, can also cause ED (NIDDK, Treatment for ED), which is part of why the link is hard to untangle.

How much do ED pills raise the risk of NAION?

The published estimates point to a small absolute increase, and the labels say it has not been shown to be cause and effect. A case-crossover study across 102 eye centers in the US and Europe found about a twofold higher risk of NAION when a PDE5 inhibitor had been taken within roughly five half-lives before symptoms began, compared with a man’s own earlier use; the authors estimated that weekly use adds about three NAION cases per 100,000 men aged 50 and over each year (Campbell et al., J Sex Med 2015). Both ED labels cite its result alongside a second study with a similar estimate. The labels then state that neither the rare post-marketing reports nor these observational studies “substantiate a causal relationship” (Cialis prescribing information, DailyMed).

A larger insurance-claims study of 213,033 men prescribed PDE5 inhibitors pointed the same way. After adjusting for high blood pressure, heart disease, smoking and diabetes, regular users had about twice the rate of ischemic optic neuropathy compared with non-users and a higher rate of serous retinal detachment (fluid building up under the retina). The estimate for retinal vascular occlusion (a blocked blood vessel in the retina) was also higher, but its range of uncertainty included no difference. The authors concluded that regular users “might have an increased risk” and should tell their physicians about any change in vision (Etminan et al., JAMA Ophthalmol 2022). Observational studies like these show an association; they cannot prove the pill caused the problem.

Is a blue tint the same thing?

No. A blue or green tint, extra sensitivity to light or slightly blurred vision is a known, temporary side effect, and it is a different thing from sudden vision loss. The labels explain that it comes from the drug partly blocking PDE6, an enzyme the retina uses to process light. In the label’s vision testing, single doses caused a temporary, dose-related difficulty telling blue from green, peaking around the time the drug is at its highest level in the blood, with no effect on sharpness of vision or eye pressure (Viagra prescribing information, DailyMed).

The labels point to the tint being more of a sildenafil effect than a tadalafil one, though their trial figures were counted differently. The Viagra label describes sildenafil as only about 10 times more potent on its target, PDE5, than on PDE6 (the Cialis label puts tadalafil at 700 times), and in its flexible-dose trials abnormal vision was reported by 3% of men against 0% on placebo, described as mild and transient. The Cialis label says that across all its clinical studies, reports of changes in color vision were rare, under 0.1% of men (Viagra; Cialis prescribing information, DailyMed). Our pages on sildenafil side effects and tadalafil side effects cover the common effects of each drug in more detail.

The practical line: a tint that fades as the drug wears off is the expected effect. Vision that goes dark, dim or missing in part or all of one or both eyes is not, and it is the one that needs care.

What about glaucoma and other eye problems with tadalafil or sildenafil?

Neither the Viagra nor the Cialis label mentions glaucoma. What the labels do report is that in their vision studies, sildenafil and tadalafil had no effect on intraocular pressure (the eye pressure that glaucoma care tracks), and the Viagra label lists increased intraocular pressure among eye events reported after approval, without a frequency or an established link (Viagra; Cialis prescribing information, DailyMed). That is not evidence either way for a particular man with glaucoma, which is why the eye doctor and the prescriber should both know.

The labels are more specific about other eye conditions:

• A past episode of NAION. Men who have had NAION are at higher risk of it happening again, so both labels say these pills should be used with caution and only when the expected benefits outweigh the risks.
• A “crowded” optic disc. The labels say this raises NAION risk, but that the evidence is not enough to support screening every man before he starts.
• Retinitis pigmentosa and other inherited retinal diseases. The Viagra label advises caution, because there are no controlled data in these men and a minority have inherited problems with retinal phosphodiesterases. The Cialis label says men with known hereditary degenerative retinal disorders were not included in its trials and that use in them is not recommended.

Sources: Viagra section 5.3 and Cialis section 5.4, DailyMed. The Cialis label’s list of eye effects from its trials also includes blurred vision, eye pain, red or irritated eyes, watery eyes and swollen eyelids; reports after approval add visual field defects and blocked retinal veins or arteries.

What does the hearing loss warning mean?

The labels describe sudden decrease or loss of hearing, sometimes with tinnitus and dizziness, reported “in temporal association” with taking PDE5 inhibitors, meaning it happened around the time of use. In some cases other medical conditions may have played a role, follow-up information was often limited, and the labels say it is not possible to tell whether the events were caused by the drugs, by a man’s own risk factors for hearing loss, or by something else (Viagra; Cialis prescribing information, DailyMed).

A review of the reports, published with two case histories, notes that in 2007 the FDA reviewed 113 reports of hearing loss in men using PDE5 inhibitors and found 29 that held up after exclusions. In the earlier case reviews it summarizes, the hearing loss usually affected one ear and often began within 24 hours of taking a pill, and only some men regained their hearing. One of those reviews called the data not conclusive, and Barreto and Bahmad said larger studies with control groups are needed (Barreto and Bahmad, Braz J Otorhinolaryngol 2013).

Sudden hearing loss of this kind is called sudden sensorineural hearing loss, or sudden deafness. The National Institute on Deafness and Other Communication Disorders (NIDCD) describes it as a rapid, unexplained loss of hearing, all at once or over a few days, often in one ear, often noticed on waking or when using a phone, and sometimes with a pop, a feeling of fullness, ringing or dizziness (NIDCD, Sudden Deafness).

What should you do if it happens?

Stop taking the ED pill and get medical attention promptly; do not take another dose to see whether it happens again. That is the instruction on both labels for sudden vision loss and sudden hearing loss (Viagra; Cialis prescribing information, DailyMed). Tell whoever sees you which pill you took and roughly when.

Speed matters most for hearing. NIDCD says sudden deafness should be treated as a medical emergency and seen by a doctor immediately: about half of people recover some or all of their hearing on their own, usually within one to two weeks, but delaying diagnosis and treatment can make treatment less effective, and timely treatment greatly raises the chance of getting some hearing back. The most common treatment is corticosteroids (NIDCD, Sudden Deafness).

Sources: Viagra and Cialis prescribing information; NIDDK; NIDCD. Only an examination can tell what is causing a sudden change, so the table is a guide to urgency, not a diagnosis.

Sources

1. Viagra (sildenafil citrate) prescribing information, sections 5.3, 5.4, 6.1, 6.2 and 12.2, DailyMed
2. Cialis (tadalafil) prescribing information, sections 5.4, 5.5, 6.1, 6.2 and 12.2, DailyMed
3. NIDDK. Treatment for Erectile Dysfunction
4. NIDCD. Sudden Deafness (Sudden Sensorineural Hearing Loss)
5. Campbell UB, et al. Acute nonarteritic anterior ischemic optic neuropathy and exposure to phosphodiesterase type 5 inhibitors. J Sex Med. 2015;12(1)
6. Etminan M, et al. Risk of ocular adverse events associated with use of phosphodiesterase 5 inhibitors in men in the US. JAMA Ophthalmol. 2022;140(5)
7. Barreto MA, Bahmad F Jr. Phosphodiesterase type 5 inhibitors and sudden sensorineural hearing loss. Braz J Otorhinolaryngol. 2013;79(6)
8. Kaur K, Margolin E. Nonarteritic Anterior Ischemic Optic Neuropathy. StatPearls (PubMed record)