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Asendin Side Effects

Generic Name: amoxapine

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

For the Consumer

Applies to amoxapine: oral tablet

In addition to its needed effects, some unwanted effects may be caused by amoxapine (the active ingredient contained in Asendin). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when 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

If any of the following symptoms of overdose occur while taking amoxapine, get emergency help immediately:

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

Minor Side Effects

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

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]


Common (1% to 10%): Anxiety, insomnia, excitement, nightmares
Frequency not reported: Hypomania, delusions, suicidality[Ref]

Nervous system

Very common (10% or more): Drowsiness (14%)
Common (1% to 10%): Restlessness, nervousness, tremors, confusion, ataxia, alterations in EEG patterns, dizziness, headache, tingling, paraesthesias of the extremities, tinnitus, disorientation, seizures, numbness, incoordination, disturbed concentration, extrapyramidal symptoms (including, tardive dyskinesia), neuroleptic malignant syndrome, peculiar taste[Ref]


Frequency not reported: Drug fever, urticaria, photosensitization, pruritus[Ref]


Common (1% to 10%): Palpitations
Frequency not reported: Hypotension, hypertension, syncope, tachycardia, vasculitis, myocardial infarction, stroke[Ref]


Very common (10% or more): Dry mouth (14%), constipation (12%)
Common (1% to 10%): Nausea
Frequency not reported: Epigastric distress, vomiting, flatulence, abdominal pain, diarrhea, sublingual adenitis, stomatitis, black tongue[Ref]


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


Common (1% to 10%): Skin rash, increased perspiration[Ref]


Common (1% to 10%): Increased prolactin levels
Frequency not reported: Breast enlargement and galactorrhea in the female, syndrome of inappropriate antidiuretic hormone secretion, gynecomastia[Ref]


Common (1% to 10%): Edema, fatigue, weakness
Frequency not reported: Hyperthermia[Ref]


Frequency not reported: Delayed micturition, urinary retention, increased or decreased libido, impotence, menstrual irregularity, painful ejaculation, dilation of the urinary tract[Ref]


Frequency not reported: Nasal stuffiness[Ref]


Frequency not reported: Hepatitis, altered liver function[Ref]


Frequency not reported: Leukopenia, agranulocytosis[Ref]


Common (1% to 10%): Excessive appetite
Frequency not reported: Weight gain or loss[Ref]


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

Not all side effects for Asendin may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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.