SIDE EFFECTS: See also Warning section. Drowsiness, dizziness, dry mouth, blurred vision, constipation, or trouble urinating may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute. To prevent constipation, maintain a diet adequate in fiber, drink plenty of water, and exercise. If you become constipated while using this drug, consult your pharmacist for help in selecting a laxative. 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. Tell your doctor right away if any of these rare but serious side effects occur: persistent heartburn, mental/mood changes (such as anxiety, agitation, confusion), shaking, severe stomach/abdominal pain. Get medical help right away if you have any very serious side effects, including: severe dizziness, fast/irregular heartbeat, fainting, seizures, eye pain/swelling/redness, widened pupils, vision changes (such as seeing rainbows around lights at night). 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: See also Warning section. Before taking doxepin, tell your doctor or pharmacist if you are allergic to it; or to other tricyclic antidepressants (such as nortriptyline); 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. Before using this medication, tell your doctor or pharmacist your medical history, especially of: bleeding problems, breathing problems, liver problems, recent heart attack, problems urinating (such as due to enlarged prostate), overactive thyroid (hyperthyroidism), personal or family history of glaucoma (angle-closure type), personal or family history of mental/mood conditions (such as bipolar disorder, psychosis), family history of suicide, seizures, conditions that may increase your risk of seizures (such as other brain disease, alcohol/sedative withdrawal). Doxepin may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away. The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using doxepin, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death). Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using doxepin safely. This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness. If you have diabetes, this drug may make it harder to control your blood sugar levels. Monitor your blood sugar levels regularly and tell your doctor of the results. Your doctor may need to adjust your diabetes medication, exercise program, or diet. Older adults may be more sensitive to the side effects of this drug, especially dry mouth, dizziness, drowsiness, confusion, difficulty urinating and QT prolongation (see above). During pregnancy, this medication should be used only when clearly needed. Since untreated mental/mood problems (such as depression, anxiety) can be a serious condition, do not stop using this medication unless directed by your doctor. If you are planning pregnancy, become pregnant, or think you may be pregnant, immediately discuss with your doctor the benefits and risks of using this medication during pregnancy. This medication passes into breast milk and may have undesirable effects on a nursing infant. Breast-feeding while using this drug is not recommended. 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 include: arbutamine, thyroid supplements, anticholinergic drugs (such as benztropine, belladonna alkaloids), central-acting drugs to treat high blood pressure (such as clonidine, guanabenz). Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before and after treatment with this medication. Ask your doctor when to start or stop taking this medication. Other medications can affect the removal of doxepin from your body, thereby affecting how doxepin works. These drugs include cimetidine, St. John's Wort, terbinafine, drugs to treat irregular heart rate (such as quinidine/propafenone/flecainide), antidepressants (such as SSRIs including paroxetine/fluoxetine/fluvoxamine). This is not a complete list. Many drugs besides doxepin may affect the heart rhythm (QT prolongation in the EKG), including amiodarone, cisapride, dofetilide, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), among others. Therefore, before using doxepin, report all medications you are currently using to your doctor or pharmacist. Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana, other drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine). Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain decongestants or ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

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: extreme drowsiness, hallucinations, fast/irregular heartbeat, fainting, slow/shallow breathing, seizures.