Alcohol: It is unsafe to consume alcohol with Penalgon 400mg Tablet ER. Pregnancy: Penalgon 400mg Tablet ER may be unsafe to use during pregnancy. Although there are limited studies in humans, animal studies have shown harmful effects on the developing baby. Your doctor will weigh the benefits and any potential risks before prescribing it to you. Please consult your doctor. Breastfeeding: Penalgon 400mg Tablet ER is probably unsafe to use during breastfeeding. Limited human data suggests that the drug may pass into the breastmilk and harm the baby. Driving: Penalgon 400mg Tablet ER may decrease alertness, affect your vision or make you feel sleepy and dizzy. Do not drive if these symptoms occur. Kidney: Penalgon 400mg Tablet ER is probably safe to use in patients with kidney disease. Limited data available suggests that dose adjustment of Penalgon 400mg Tablet ER may not be needed in these patients. Please consult your doctor.Regular monitoring of kidney function tests is advisable while you are taking this medicine. Liver: There is limited information available on the use of Penalgon 400mg Tablet ER in patients with liver disease. Please consult your doctor.