Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes Nitrol (Nitroglycerin). If you are concerned about side effects, discuss the risks and benefits of Nitrol (Nitroglycerin) with your doctor.

The following side effects have been reported by at least 1% of people taking Nitrol (Nitroglycerin). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• dizziness or lightheadedness, especially when getting up from a lying or sitting position
• fast heartbeat
• flushing of the face and neck
• headache
• nausea or vomiting
• restlessness
• sore, reddened skin

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• blurred vision
• dryness of the mouth
• headache (severe or prolonged)
• increased blood pressure
• irregular heartbeat

Contact a doctor at once if any of the following signs of overdose occur:

• bluish-coloured lips, fingernails, or palms of the hands
• convulsions (seizures)
• dizziness (extreme) or fainting
• feeling of extreme pressure in head
• Fever
• shortness of breath
• unusual tiredness or weakness
• weak and fast heartbeat

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a Heart Attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
• signs of methemoglobinemia (e.g., shortness of breath, blue to purplish lips, fingers or toes, severe headache, fatigue, dizziness or loss of consciousness)
• symptoms of a serious allergic reaction (such as swelling of the face, lips, tongue, or throat; skin rash; Hives; or difficulty breathing)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Nitrol (Nitroglycerin).

Each tube of ointment contains 2% Nitrol (Nitroglycerin). Nonmedicinal ingredients: lactose, lanolin, petrolatum, and purified water (all USP standard).

Do not use Nitrol (Nitroglycerin) ointment if you:

• are allergic or sensitive to Nitrol (Nitroglycerin) or any of the ingredients of the medication
• are allergic or sensitive to any organic nitrates
• are taking a PDE-5 inhibitor for Erectile Dysfunction (e.g., Sildenafil, Tadalafil, Vardenafil)
• are taking the medication Riociguat
• have acute circulatory failure associated with severe lowering of blood pressure (states of collapse or shock)
• have extremely Low Blood Pressure
• have increased eye pressure (Glaucoma)
• have increased pressure within the head (e.g., after an accident)
• have reduced heart function due to obstruction (e.g., narrowing of the heart valves)
• have severe Anemia

There may be an interaction between Nitrol (Nitroglycerin) ointment and any of the following:

• alcohol
• Aldesleukin
• alpha blockers (e.g., Alfuzosin, Doxazosin, Tamsulosin)
• alpha agonists (e.g., Clonidine, methyldopa)
• alteplase
• angiotensin converting enzyme inhibitors (ACEIs; Captopril, Enalapril, Ramipril)
• angiotensin receptor blockers (ARBs; e.g., candasartan, Irbesartan, Losartan)
• barbiturates (e.g., butalbital, pentobarbital Phenobarbital)
• beta-adrenergic blockers (e.g., Atenolol, Propranolol, Sotalol)
• Aripiprazole
• brimonidine
• Bromocriptine
• Cabergoline
• calcium channel blockers (e.g., Amlodipine, Diltiazem, Nifedipine, Verapamil)
• clonidine
• Dipyridamole
• diuretics (water pills; e.g., Furosemide, Hydrochlorothiazide, triamterene)
• ergot derivatives (e.g., Dihydroergotamine, ergotamine, ergonovine, methylergonovine)
• Duloxetine
• Guanfacine
• Heparin
• Hydralazine
• other nitrates (e.g., Nitrol (Nitroglycerin), isosorbide dinitrate, isosorbide mononitrate)
• Quetiapine
• reserpine
• riociguat
• Risperidone
• Rosiglitazone
• phosphodiesterase -5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
• riociguat

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Nitrol (Nitroglycerin).

Acute angina attacks: Nitrol (Nitroglycerin) ointment is not intended for immediate relief of acute attacks of angina. Sublingual (under the tongue) Nitrol (Nitroglycerin) preparations (spray or tablets) should be used for this purpose.

Dizziness/reduced alertness: People using Nitrol (Nitroglycerin) may experience faintness or dizziness and reduced reaction time when driving or operating machinery, especially at the start of treatment. Avoid these and other hazardous tasks until you have determined how Nitrol (Nitroglycerin) affects you.

Heart attacks: Not enough information exists on the safety of using Nitrol (Nitroglycerin) ointment during the early phase of a heart attack. If you suspect you are having a heart attack, call 9-1-1.

Low blood pressure: Headaches or symptoms of low blood pressure such as weakness or dizziness, particularly when getting up suddenly from a sitting or lying down position, may result from taking too much Nitrol (Nitroglycerin). If these symptoms occur, your doctor may reduce the dose or stop the use of Nitrol (Nitroglycerin). People who might be negatively affected by low blood pressure should use Nitrol (Nitroglycerin) ointment with caution. People who take diuretics or have preexisting low blood pressure may be at more risk of being negatively affected.

PDE-5 inhibitors: PDE-5 inhibitors (e.g. sildenafil, tadalafil, vardenafil) should never be taken with Nitrol (Nitroglycerin). Blood pressure may suddenly drop to life-threatening levels if these medications are combined. They may cause dizziness, fainting spells, heart attack, or Stroke.

Tolerance: People taking Nitrol (Nitroglycerin) may develop tolerance to the medication, resulting in it not working as well. Tolerance to other nitrates or nitrites can also develop, especially if a medication-free period is not observed each day.

Withdrawal: Dependence may occur with chronic use. To avoid possible withdrawal effects, reduce Nitrol (Nitroglycerin) ointment use gradually over 4 to 6 weeks.

Pregnancy: Nitrol (Nitroglycerin) has not been studied for use by pregnant women. Be sure to tell your doctor if you are pregnant or planning to become pregnant.

Breast-feeding: It is not known if Nitrol (Nitroglycerin) passes into breast milk. Be sure to discuss with your doctor the risks and benefits of using Nitrol (Nitroglycerin) before breast-feeding.

Children: The safety and effectiveness of Nitrol (Nitroglycerin) for children have not been established.