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Asendin Side Effects

Generic Name: amoxapine

Note: This document contains side effect information about amoxapine. Some of the dosage forms listed on this page may not apply to the brand name Asendin.

For the Consumer

Applies to amoxapine: oral tablet

Along with its needed effects, amoxapine (the active ingredient contained in Asendin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking amoxapine:

Less common
  • Excitement
  • fast, irregular, pounding, or racing heartbeat or pulse
  • fear or nervousness
  • mood or mental changes
  • nightmares
  • restlessness
  • shakiness and unsteady walk
  • shakiness in legs, arms, hands, or feet
  • sleeplessness
  • swelling
  • trouble sleeping
  • unable to sleep
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • Abdominal or stomach pain
  • actions that are out of control
  • black, tarry stools
  • bleeding gums
  • bloating
  • blood in urine or stools
  • blurred vision
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • chest pain or discomfort
  • chills
  • clay-colored stools
  • confusion
  • confusion about identity, place, and time
  • constipation
  • continuing ringing or buzzing or other unexplained noise in ears
  • convulsions
  • cough or hoarseness
  • dark urine
  • decrease in frequency of urination
  • decrease in urine volume
  • difficulty in breathing
  • difficulty in passing urine (dribbling)
  • difficulty in speaking
  • disturbed concentration
  • dizziness, faintness, or lightheadedness when getting up from a lying or sitting position suddenly
  • double vision
  • drooling
  • extremely high fever or body temperature
  • false beliefs that cannot be changed by facts
  • fast, weak heartbeat
  • fever with or without chills
  • general feeling of tiredness or weakness
  • headache
  • hearing loss
  • high fever
  • high or low blood pressure
  • hives or welts
  • inability to move arms, legs, or facial muscles
  • inability to speak
  • increased need to urinate
  • increased sweating
  • indigestion
  • irritability
  • itching
  • lack of coordination
  • light-colored stools
  • lip smacking or puckering
  • loss of appetite
  • loss of bladder control
  • lower back or side pain
  • muscle cramps
  • muscle spasm or jerking of all extremities
  • muscle trembling, jerking, or stiffness
  • nausea and vomiting
  • nervousness
  • numbness
  • pain or discomfort in arms, jaw, back, or neck
  • painful or difficult urination
  • pains in stomach, side, or abdomen, possibly radiating to the back
  • pale, clammy skin
  • passing urine more often
  • pinpoint red spots on skin
  • pounding in the ears
  • puffing of cheeks
  • rapid or worm-like movements of tongue
  • redness of skin
  • seeing, hearing, or feeling things that are not there
  • severe muscle stiffness
  • shortness of breath
  • shuffling walk
  • skin rash
  • slow speech
  • sore throat
  • sores, ulcers, or white spots on lips or in mouth
  • stiffness of limbs
  • sudden loss of consciousness
  • sweating
  • swollen glands
  • talking, feeling, and acting with excitement
  • testicular swelling
  • thirst
  • trouble in holding or releasing urine
  • twisting movements of body
  • uncontrolled chewing movements
  • uncontrolled movements, especially of face, neck, and back
  • unpleasant breath odor
  • unusual bleeding or bruising
  • unusually pale skin
  • upper right abdominal pain
  • vomiting of blood
  • yellow eyes and skin

Get emergency help immediately if any of the following symptoms of overdose occur while taking amoxapine:

Symptoms of overdose
  • Change in consciousness
  • drowsiness
  • epileptic seizure that will not stop
  • fatigue
  • increased blood pressure
  • increased thirst
  • loss of consciousness
  • swelling of face, fingers, or lower legs
  • total body jerking
  • troubled breathing
  • weight gain

Some side effects of amoxapine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Dry mouth
Less common
  • Increased appetite
  • increased flow of breast milk
  • Agitation
  • breast enlargement
  • change in taste bad unusual or unpleasant (after)taste
  • decreased interest in sexual intercourse
  • depression
  • excess air or gas in stomach or intestines
  • full feeling
  • hair loss, thinning of hair
  • heartburn
  • inability to have or keep an erection
  • increased in sexual ability, desire, drive, or performance
  • increased interest in sexual intercourse
  • increased sensitivity of skin to sunlight
  • loss in sexual ability, desire, drive, or performance
  • menstrual changes
  • nasal stuffiness
  • painful ejaculation
  • passing gas
  • rapid weight gain
  • redness or other discoloration of skin
  • seizures
  • severe sunburn
  • stupor
  • swollen, painful, or tender lymph glands on side of face or neck
  • tearing of the eyes
  • unexpected or excess milk flow from breasts

For Healthcare Professionals

Applies to amoxapine: oral tablet


The most commonly reported side effects were drowsiness, dry mouth, constipation, and blurred vision.[Ref]

Nervous system

Very common (10% or more): Drowsiness (up to 14%)
Common (1% to 10%): Alterations in EEG patterns, ataxia, dizziness, headache, tremors
Frequency not reported: Disturbed concentration, extrapyramidal symptoms, incoordination, mydriasis, neuroleptic malignant syndrome, numbness, paresthesia of the extremities, peculiar taste, seizures, stroke, syncope, tardive dyskinesia, tingling[Ref]


Very common (10% or more): Dry mouth (up to 14%), constipation (up to 12%)
Common (1% to 10%): Nausea
Frequency not reported: Abdominal pain, black tongue, diarrhea, epigastric distress, flatulence, pancreatitis, paralytic ileus, parotid swelling, stomatitis, sublingual adenitis, vomiting[Ref]


Common (1% to 10%): Anxiety, confusion, excitement, insomnia, nervousness, nightmares, restlessness
Frequency not reported: Delusions, disorientation, hallucinations, hypomania, increased or decreased libido, suicidality[Ref]


Common (1% to 10%): Edema, palpitations
Frequency not reported: Atrial arrhythmias, atrial fibrillations, heart block, hypertension, hypotension, myocardial infarction, tachycardia, vasculitis[Ref]


Common (1% to 10%): Increased perspiration, skin rash
Frequency not reported: Alopecia, petechia, photosensitization, pruritus, urticaria[Ref]


Common (1% to 10%): Fatigue, weakness
Frequency not reported: Drug fever, hyperthermia, tinnitus[Ref]


Common (1% to 10%): Excessive appetite
Frequency not reported: Anorexia, change in blood glucose levels, weight gain or loss[Ref]


Common (1% to 10%): Increased prolactin levels
Frequency not reported: Gynecomastia, syndrome of inappropriate antidiuretic hormone secretion[Ref]


Common (1% to 10%): Blurred vision
Frequency not reported: Disturbances of accommodation, lacrimation[Ref]


Frequency not reported: Breast enlargement, delayed micturition, dilation of the urinary tract, galactorrhea, impotence, menstrual irregularity, painful ejaculation, testicular swelling, urinary frequency, urinary retention[Ref]


Frequency not reported: Agranulocytosis, eosinophilia, leukopenia, purpura, thrombocytopenia[Ref]


Frequency not reported: Altered liver function, hepatitis, jaundice[Ref]


Frequency not reported: Nasal stuffiness[Ref]


1. "Product Information. Asendin (amoxapine)" Lederle Laboratories, Wayne, NJ.

Some side effects of Asendin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.