Short answer: usually nothing dramatic happens — and that is exactly the trap. The dominant risk of an expired PDE5 inhibitor is loss of potency, not toxicity: the active ingredient degrades slowly, so the dose you actually swallow becomes unknown.
How long these tablets are actually good for
Sildenafil and tadalafil tablets typically carry a shelf life of about three years from manufacture, printed on the blister and the carton. That figure assumes an intact tablet in its original packaging, kept at room temperature and away from moisture. Registered generics carry the same class of shelf life as the brands — the expiry date is a property of the formulation and its packaging, not of the name on the box.
What the date actually promises is narrow and worth understanding: the manufacturer guarantees that, stored properly, the tablet still contains the stated amount of active ingredient and behaves as tested up to that day. It is a guarantee with an end date, not a cliff the chemistry falls off.
What happens after the date
Degradation is gradual. A few months past expiry, a well-stored tablet usually retains most of its potency — but nobody certifies that any more, and "usually" is doing real work in that sentence. Years past the date, or after a summer in a hot car or a steamy bathroom cabinet, the effect becomes unpredictable: sometimes reduced, sometimes absent.
The failure mode matters more than the probability. A blood-pressure tablet that has lost 20% of its potency quietly under-treats you. An erection tablet that has lost 20% of its potency simply disappoints — and then invites the decision that actually causes harm.
The real risk is doubling up
An expired tablet that "does nothing" invites a second one, and that is where an expired strip becomes genuinely dangerous: you are stacking an unknown leftover dose onto a full dose, and the side effects of a PDE5 inhibitor — the blood-pressure drop especially — scale with the amount in your system.
So the rule does not change for old tablets: never more than one dose in 24 hours. If you feel unwell after taking an expired tablet — chest pain, fainting, a headache unlike your usual — treat it as you would any adverse reaction and get medical advice. An erection lasting more than four hours needs urgent care regardless of the tablet's age.
What to do with the strip in your drawer
| Situation | Sensible course |
|---|---|
| In date, stored properly | Use normally |
| A few months past, original blister, cool and dry | Grey zone — likely still active, no longer guaranteed. Replacing costs a few dollars a pill |
| Years past, or stored in heat or humidity | Do not use. Return it to a pharmacy |
| Discoloured, crumbling, sticky, or the blister is damaged | Do not use, whatever the printed date says |
Because replacement is cheap, the calculation almost always favours a fresh strip: current per-pill prices are on generic Viagra (sildenafil) and generic Cialis (tadalafil). Do not put old medicines in the bin or the toilet — Australian pharmacies take them back free, which we cover in storing and disposing of medicines.
Making the date irrelevant
Most expired ED tablets are expired because they were bought in bulk and used rarely. If that describes you, buy the pack size you will realistically use within a year or two rather than the largest one on the page — the per-pill saving on a big pack is a false economy if a third of it ends up at the pharmacy counter. Storing them properly does the rest: dry, cool, in the blister.
Sources
- TGA — Therapeutic Goods Administration: medicine expiry, stability and storage requirements
- Healthdirect — Using medicines safely
