Tadalafil (Generic) and Pregabalin Interaction: What Patients and Clinicians Need to Know
Do these drugs change each other's blood levels?
Pregabalin leaves the body mainly unchanged through the kidneys and has little metabolism. Tadalafil is primarily metabolized through CYP3A4. A direct metabolic interaction is therefore not expected from their labeled pharmacology. Neither label names the other drug as a specific interaction. Lyrica prescribing information, Cialis prescribing information
This helps answer the blood-level question. It does not decide whether a particular patient is comfortable walking, driving or standing after treatment changes. Those are tolerability questions that require attention to actual symptoms.
Dizziness and sleepiness are different symptoms
Pregabalin's adult controlled trials reported dizziness in 30% of treated participants versus 8% receiving placebo, and sleepiness in 23% versus 8%. Effects were more frequent at higher doses. These are pregabalin trial figures, not measurements of this combination. Lyrica prescribing information
Tadalafil should not be classified as a central nervous system depressant simply because some people feel dizzy while taking it. NHS guidance notes that it usually does not impair driving, but people who become dizzy should wait for that to resolve. NHS tadalafil guidance
Describing the symptom precisely helps the prescriber:
| Description | Useful details to record |
|---|---|
| Sleepy or mentally slowed | Whether it followed a pregabalin dose or dose increase |
| Lightheaded on standing | When it occurred and whether a blood-pressure reading was available |
| Unsteady while walking | Whether there was a near-fall, a fall or an injury |
| Symptoms after adding a medicine | Start date, dose and the other medicines taken that day |
Feeling dizzy does not automatically prove low blood pressure. Likewise, a normal reading does not rule out medication-related sleepiness or impaired coordination.
How does kidney function change the review?
Pregabalin dosing is adjusted using kidney function. Its dose should be checked against the indication and the relevant creatinine-clearance range, rather than applying one standard daily amount to everyone. Lyrica prescribing information
Tadalafil also behaves differently with reduced kidney function. In clinical pharmacology studies, exposure was approximately doubled in participants with mild or moderate renal impairment. Dialysis contributed little to its removal. The same publication found no substantial change in exposure in mild or moderate hepatic impairment, illustrating why liver disease should not automatically be described as causing a fixed increase in tadalafil concentration. Forgue et al., 2007
Current tadalafil instructions distinguish daily treatment from as-needed treatment when setting renal restrictions. Severe hepatic impairment is also treated differently from mild or moderate impairment. Cialis prescribing information
For a medication review, bring the latest kidney result if available and the actual prescription schedules. A diagnosis of kidney disease alone does not tell a clinician whether a particular dose is appropriate.
Does age alone require changing both doses?
Age is useful context, but symptoms, kidney function and the rest of the medication list are more informative than a universal rule to reduce both medicines. The tadalafil pharmacokinetic study found different effects from aging and renal impairment; those should not be treated as the same adjustment. Forgue et al., 2007
A person who has recently fallen or feels unsteady merits a focused review. Record what happened and when, including whether symptoms appeared after either prescription changed. An age cutoff alone does not establish that the combination caused the problem.
What about alcohol and other medicines?
Avoid alcohol with pregabalin because it can increase sleepiness and loss of concentration. Alcohol can also increase lightheadedness with tadalafil. The advice follows each medicine's effects; it does not require an invented three-drug interaction rate. NHS pregabalin guidance, NHS tadalafil guidance
Other medicines that make a person sleepy or dizzy can worsen pregabalin's effects. A review should include pain medicines, sleeping medicines and any other sedating products, alongside blood-pressure treatment. NHS medicine-interaction guidance
The useful question is what was actually taken, not just what appears on an old prescription list. Include occasional doses and recently stopped medicines when describing a new symptom.
What should happen if symptoms appear?
If mild dizziness or sleepiness follows a change, contact the prescriber to review the dose and timing. Avoid driving or hazardous tasks while affected. Keep a short record of the symptom, its timing and any dose changes. NHS pregabalin side-effect guidance
Do not abruptly stop pregabalin to test whether it is responsible. Its label calls for gradual withdrawal over at least one week, with an individualized plan. Lyrica prescribing information
Fainting, an injured fall, chest pain or substantial shortness of breath needs urgent assessment. An erection lasting more than four hours also needs emergency treatment. Persistent lightheadedness warrants a prompt prescriber review rather than waiting for a routine appointment. Cialis prescribing information
Frequently asked questions
Is tadalafil a sedative like pregabalin?
Does pregabalin make tadalafil levels rise?
Should I separate the tablets by several hours?
Should I stop pregabalin if I feel dizzy after tadalafil?
References
- Pfizer. Lyrica pregabalin prescribing information.
- Eli Lilly. Cialis prescribing information, revised March 2026.
- Forgue et al. Tadalafil pharmacokinetics in renal impairment, hepatic impairment and other populations. 2007.
- NHS. Tadalafil.
- NHS. Common questions about pregabalin.
- NHS. Taking pregabalin with other medicines.
- NHS. Side effects of pregabalin.
