Also known as: Norfloxacin
Grenis comes as a tablet to take by mouth. It is usually taken twice a day for 3 to 28 days. The length of treatment depends on the type of infection being treated. Your doctor will tell you how long to take Grenis. Take Grenis at around the same times every day and try to space your doses 12 hours apart. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take Grenis exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Take Grenis at least 1 hour before or 2 hours after meals or after drinking milk or eating dairy products.
Swallow the tablets with a full glass of water.
You should begin to feel better during the first few days of your treatment with Grenis. If your symptoms do not improve or if they get worse, call your doctor.
Take Grenis until you finish the prescription, even if you feel better. Do not stop taking Grenis without talking to your doctor unless you experience certain serious side effects listed in the IMPORTANT WARNING or SIDE EFFECT sections. If you stop taking Grenis too soon or if you skip doses, your infection may not be completely treated and the bacteria may become resistant to antibiotics.
Grenis is also sometimes used to treat certain infections of the stomach and intestines. Talk to your doctor about the risks of using this medication for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking Grenis tell your doctor and pharmacist if you are allergic or have had a severe reaction to Grenis; other quinolone or fluoroquinolone antibiotics such as ciprofloxacin (Cipro), gatifloxacin (Tequin) (not available in the U.S.), gemifloxacin (Factive), levofloxacin (Levaquin), lomefloxacin (Maxaquin) (not available in the U.S.), moxifloxacin (Avelox), nalidixic acid (NegGram), ofloxacin (Floxin), and sparfloxacin (Zagam) (not available in the U.S.), or any other medications.
Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, herbal products, and nutritional supplements you are taking or plan to take. Be sure to mention the medications listed in the IMPORTANT WARNING section and any of the following: other antibiotics; anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); certain antidepressants; antipsychotics (medications to treat mental illness); caffeine or medications that contain caffeine (Excedrin, NoDoz, Vivarin, others); cisapride (Propulsid) (not available in the U.S.); clozapine (Clozaril, Fazaclo); cyclosporine (Gengraf, Neoral, Sandimmune); diuretics ('water pills'); erythromycin (E.E.S, E-Mycin, Erythrocin, others); glyburide (DiaBeta, in Glucovance, Micronase, others); certain medications for irregular heartbeat such as amiodarone (Cordarone), procainamide (Procanbid), quinidine, and sotalol (Betapace, Betapace AF, Sorine); nitrofurantoin (Furadantin, Macrobid, Macrodantin); probenecid (in Col-Probenecid, Probalan); nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin, others) and naproxen (Aleve, Naprosyn, others); ropinirole (Requip); tacrine (Cognex); theophylline (Elixophyllin, Theo-24, Uniphyl, others); and tizanidine (Zanaflex). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
If you are taking antacids containing aluminum hydroxide or magnesium hydroxide (Maalox, Mylanta, Tums, others), didanosine (Videx) sucralfate (Carafate), or supplements or multivitamins that contain iron or zinc, take these medications 2 hours before or 2 hours after you take Grenis.
Tell your doctor if you or anyone in your family has or has ever had a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting or sudden death) or an irregular heartbeat and if you have or have ever had nerve problems, a low level of potassium in your blood, a slow heartbeat, chest pain, seizures, myasthenia gravis (condition that causes weakness of certain muscles), cerebral arteriosclerosis (narrowing of blood vessels in or near the brain that can lead to stroke or mini-stroke), or glucose-6-phosphate dehydrogenase (G-6PD) deficiency (an inherited blood disorder).
Tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking Grenis, call your doctor.
You should know that this medication may cause dizziness, lightheadedness, and tiredness. Do not drive a car, operate machinery, or participate in activities requiring alertness and coordination until you know how Grenis affects you.
Plan to avoid unnecessary or prolonged exposure to sunlight or ultraviolet light (tanning beds and sunlamps) and to wear protective clothing, sunglasses, and sunscreen. Grenis may make your skin sensitive to sunlight or ultraviolet light. If your skin becomes reddened, swollen, or blistered, call your doctor.
If you overdose Generic Grenis and you don't feel good you should visit your doctor or health care provider immediately.
Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.