SIDE EFFECTS: Headache, runny/stuffy nose, nausea, upset stomach, or flushing of the face may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Desmopressin reduces the amount of urine your kidneys make. It may affect the balance of water and minerals in your body. Desmopressin can rarely cause a low level of sodium in the blood, which can be serious and possibly life-threatening. Drinking too much water or other fluids increases the risk of having a low level of sodium in the blood. Therefore, follow your doctor's directions for limiting fluids. Seek immediate medical attention if you have any of these unlikely but serious symptoms of a low level of sodium in the blood: loss of appetite, severe nausea, vomiting, severe headache, muscle weakness/spasms/cramps, sudden weight gain, unusual tiredness, unusual severe drowsiness, mental/mood changes (such as confusion, hallucinations, irritability), loss of consciousness, seizures, slow/shallow breathing. A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before using desmopressin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: kidney disease, a low level of sodium in the blood (current or past hyponatremia). Before using this medication, tell your doctor or pharmacist your medical history, especially of: high blood pressure, heart disease (such as blocked blood vessels in the heart), conditions that may increase your risk of fluid/mineral imbalance (such as cystic fibrosis, heart failure), the urge to drink too much water without being thirsty. If you have lost too much body water (become dehydrated), your doctor will correct that condition first before starting treatment with desmopressin. Limit alcohol because it can interfere with how well desmopressin works. Changes inside the nose (such as scarring, swelling, congestion, or blockage) may affect how well desmopressin nasal spray is absorbed. Tell your doctor if you have any of these changes inside the nose because he or she may need to adjust your treatment. Tell the doctor right away if you develop any illness that can cause water/mineral imbalance (including fever, diarrhea, vomiting, infections such as the flu) or if you experience conditions that require drinking more fluids (for example, exposure to very hot weather, strenuous exercise, persistent sweating). The doctor may need to stop or adjust desmopressin treatment, especially in children and older adults. Children may be more sensitive to the side effects of this drug, especially water/mineral imbalance and a low level of sodium in the blood. Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, older adults may be at greater risk for water/mineral imbalance and a low level of sodium in the blood while using this drug. During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor. This medication passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Some products that may interact with this drug are: tolvaptan, "water pills"/diuretics (such as furosemide).

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: confusion, drowsiness, persistent/severe headache, sudden weight gain.