Lorcaserin Side Effects

In Summary

Commonly reported side effects of lorcaserin include: headache, hypoglycemia, decreased hemoglobin, euphoria, and lymphocytopenia. Other side effects include: constipation, dizziness, fatigue, increased serum prolactin, nausea, and xerostomia. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to lorcaserin: oral tablet, oral tablet extended release

Along with its needed effects, lorcaserin 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 lorcaserin:

• Anxiety
• bladder pain
• bloody or cloudy urine
• blurred vision
• body aches or pain
• chills
• cold sweats
• coma
• confusion
• cool, pale skin
• cough
• depression
• difficult, burning, or painful urination
• difficulty with breathing
• dizziness
• ear congestion
• fast heartbeat
• fever
• frequent urge to urinate
• headache
• increased hunger
• loss of voice
• lower back or side pain
• nasal congestion
• nausea
• nightmares
• pounding in the ears
• runny nose
• seizures
• shakiness
• slow or fast heartbeat
• slurred speech
• sneezing
• sore throat
• swelling of the breasts or breast soreness in both females and males
• unexpected or excess milk flow from the breasts
• unusual tiredness or weakness

• Bloating or swelling of the face, arms, hands, lower legs, or feet
• decreased ability to exercise
• dry mouth
• flushed, dry skin
• fruit-like breath odor
• increased hunger
• increased sensitivity to sunlight
• increased thirst
• increased urination
• itching, pain, redness, or swelling of the eye or eyelid
• joint pain
• loss of consciousness
• rapid weight gain
• severe skin rash or hives
• stomachache
• sweating
• swollen glands
• tingling of the hands or feet
• trouble with breathing
• trouble with sleeping
• unexplained weight loss
• unusual weight gain or loss
• vomiting
• watering of the eyes

• Black, tarry, stools
• chest pain
• cough or hoarseness
• pale skin
• sores, ulcers, or white spots on the lips or in the mouth
• swollen glands
• unusual bleeding or bruising

• Agitation
• confusion
• convulsions
• diarrhea
• high fever
• increased sweating
• loss of bladder control
• overactive reflexes
• painful or prolonged erection of the penis
• poor coordination
• restlessness
• severe muscle stiffness
• shivering
• talking or acting with excitement you cannot control
• trembling or shaking
• twitching
• unusually pale skin

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

• Abdominal or stomach discomfort
• false or unusual sense of well-being
• seeing, hearing, or feeling things that are not there

Some side effects of lorcaserin 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:

• Back pain
• difficulty having a bowel movement (stool)
• muscle aches

• Decreased appetite
• difficulty with concentration
• dry eyes
• muscle spasms
• muscle, joint, or bone pain
• problems with memory
• rash
• sleeplessness
• stress
• toothache
• trouble seeing

For Healthcare Professionals

Applies to lorcaserin: oral tablet, oral tablet extended release

Nervous system

Very common (10% or more): Headache (up to 16.8%)
Common (1% to 10%): Dizziness, impaired attention/memory
Uncommon (0.1% to 1%): Tremor, confusion, disorientation
Very rare (less than 0.01%): Serotonergic excess
Frequency not reported: Neuroleptic Malignant Syndrome/serotonin syndrome, somnolence^[Ref]

Cardiovascular

Common (1% to 10%): Hypertension
Uncommon (0.1% to 1%): Regurgitant cardiac valvular heart disease, bradycardia^[Ref]

Psychiatric

Common (1% to 10%): Anxiety, insomnia, stress, depression/mood problems
Uncommon (0.1% to 1%): Euphoria, suicidal ideation
Frequency not reported: Hallucination, dissociation^[Ref]

Hematologic

Very common (10% or more): Decreased lymphocyte count (up to 12.2%), decreased hemoglobin (up to 10.4%)
Common (1% to 10%): Decreased red blood cell count, decreased neutrophil count
Uncommon (0.1% to 1%): Decreased white blood cell count^[Ref]

Endocrine

Very common (10% or more): Hypoglycemia (up to 29.3%)
Common (1% to 10%): Worsening of diabetes mellitus, elevated prolactin^[Ref]

Respiratory

Very common (10% or more): Upper respiratory tract infection (up to 13.7%), nasopharyngitis (up to 13%)
Common (1% to 10%): Cough, oropharyngeal pain, sinus congestion^[Ref]

Other

Common (1% to 10%): Fatigue, peripheral edema, chills^[Ref]

General

The most common adverse reactions for non-diabetic patients were headache, dizziness, fatigue, nausea, dry mouth, and constipation. For diabetic patients, the most common adverse reactions were hypoglycemia, headache, back pain, cough, and fatigue.^[Ref]

Dermatologic

Common (1% to 10%): Rash
Uncommon (0.1% to 1%): Hyperhidrosis^[Ref]

Gastrointestinal

Common (1% to 10%): Nausea, diarrhea, constipation, dry mouth, vomiting, toothache, gastroenteritis^[Ref]

Genitourinary

Common (1% to 10%): Urinary tract infection^[Ref]

Immunologic

Common (1% to 10%): Seasonal allergy^[Ref]

Metabolic

Common (1% to 10%): Decreased appetite^[Ref]

Musculoskeletal

Very common (10% or more): Back pain (up to 11.7%)
Common (1% to 10%): Musculoskeletal pain, muscle spasms^[Ref]

Ocular

Non-diabetic patients experienced events of blurred vision, dry eye, and visual impairment. Diabetic patients experienced visual disorders, conjunctival infections, irritations and inflammations, ocular sensation disorders, and cataract conditions.^[Ref]

Common (1% to 10%): Eye disorder^[Ref]

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer