Other warning signs of an unsafe online pharmacy include outdated medication, no customer service, or suspiciously low prices. Generic vs. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. The generic versions are just as effective and much less expensive. Medicines that you take by mouth are called oral medicines. ED medications can cause side effects, and it’s crucial to have access to a medical provider if needed.Tadalafil is in a class of drugs called phosphodiesterase-5 (PDE5) inhibitors and is available in a generic form often called generic Cialis. Tadalafil has been on the . It may also be used to treat the enlargement of the prostate gland. This drug is slightly more popular than comparable drugs. It is available in both brand and generic versions. Cialis . Best Low Cost: GoodRx Fastest Delivery: Blink Health: Sesame Sign Up Now Key Specs Cost: Consultation prices vary based on the prescriber; $5 generic .