You will have more information to make regarding your treatment after this conversation. Penegra, like other drugs in the phosphodiesterase type 5 (PDE5) inhibitor class, is safe and usually regarded as effective when taken as directed by a doctor. All medications, though, have possible adverse effects, so it's important to be aware of them. Never self-prescribe Penegra or change the dosage without first speaking with a medical provider. Contact your healthcare practitioner as soon as possible if you are having any side effects or have questions about using the drug for an extended period of time.