Erectile dysfunction medicines and interactions: what is important

Editorial illustration of a consultation with a list of medications to check interactions. — AI-generated photorealistic illustrative image. Original editorial illustration; not a depiction of a treatment result.

Interactions depend on the specific active ingredient and the agents used at the same time. This guide covers PDE5 inhibitors such as sildenafil and tadalafil, which are prescribed for erectile dysfunction. It is not an approval of any particular combination. Medications and recreational drugs that are used occasionally must be mentioned during the medical consultation.

How your medicine list is checked

Interaction testing: excluded combinations, other agents, complete medication list and personal assessment.

Schematic overview. The explanations and sources in the article also apply to this graphic.

Combinations with particularly high risk

Medicine or group	Why the combination is problematic	What needs to be clarified before treatment
Nitrates and nitric oxide donors	A dangerous reduction in blood pressure is possible; the combination is contraindicated.	Also specify nitro spray and heart medication only used when necessary.
Poppers	These nitrites can greatly increase the blood pressure-lowering effect.	Address consumption openly; do not use a combination.
Riociguat	Concomitant use with PDE5 inhibitors is contraindicated.	The treating specialist must assess the entire medication.
Alpha blockers and blood pressure medications	Depending on the active ingredient and the situation, blood pressure can also drop.	List the preparations, doses and circulatory problems in full.

Why antibiotics or HIV medications can also be relevant

Sildenafil and tadalafil are broken down with the participation of the enzyme CYP3A4. Some medicines inhibit this breakdown and can increase the exposure to the PDE5 inhibitor. These include, for example, certain HIV medications, some antifungal medications and certain antibiotics. Other medicines can speed up the breakdown. The exact substance and the product information are crucial, not just the name of the medication group.

Grapefruit products are also relevant for the interaction check. This does not mean that every antibiotic or every food causes the same interaction. A pharmacy or treating doctor can check the specific list. A time interval alone does not automatically make a dangerous combination safe.

Erectile dysfunction medicines and alcohol

Alcohol can impair erectile function and cause circulatory problems. In larger quantities, the combination, especially with Tadalafil, can contribute to dizziness when standing up or a drop in blood pressure. No generally safe drinking amount for every person can be derived from individual studies. Pre-existing conditions and other medications must be taken into account.

Combine several erectile dysfunction medicines?

The independent combination of different PDE5 inhibitors or additional medications for erectile dysfunction is not a sure way to improve the effect. The tolerability of such combinations has not been proven across the board. The existing post about high-dose sildenafil and its risks explains why a larger amount of active ingredient does not automatically mean better treatment.

A complete list protects better than memory

Write down the name and dosage of medicines used regularly and when necessary.
Also list eye drops, ointments, nutritional supplements and recreational drugs.
Mention previous fainting, drops in blood pressure and cardiovascular problems.
Ask what to do if there is no effect or side effects.

Do not omit medication for other illnesses on your own. The guide to Xarelto and erection problems deals with the important distinction between illness, symptoms and suspected medication effects.

Frequently asked questions and warning signs

Is leaving time between doses enough?

No. Breakdown times vary and risks may exist beyond the noticeable effect. Emergency measures prescribed by a doctor may not be replaced by self-calculated waiting times.

What to do if you have chest pain?

Call the emergency number 112 and state which medicine you took and when you took it. Do not use nitrates yourself after taking a PDE5 inhibitor. An erection lasting four hours or more as well as sudden visual or hearing problems also require immediate medical clarification.

Are these remedies available without a prescription?

Sildenafil, Tadalafil, Vardenafil and Avanafil for the treatment of erectile dysfunction require a prescription in Germany. A prescription does not replace checking current drug interactions.

Related guides

Sildenafil and Tadalafil: the main differences