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
Side effects requiring immediate medical attention
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:
More common
- 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
Less common
- 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
Rare
- 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
Incidence not known
- 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:
Symptoms of overdose
- Abdominal or stomach discomfort
- false or unusual sense of well-being
- seeing, hearing, or feeling things that are not there
Side effects not requiring immediate medical attention
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:
More common
- Back pain
- difficulty having a bowel movement (stool)
- muscle aches
Less common
- 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]
Oncologic
Frequency not reported: Increased incidence of cancer[Ref]
The U.S. Food and Drug Administration (FDA) reports that safety data from a lorcaserin clinical trial shows a possible increased risk of cancer. In this trial of 12,000 participants over 5 years, more patients taking lorcaserin were diagnosed with cancer compared to patients taking placebo. The cause of the cancer is uncertain, and it is unknown if this drug contributed to the cancer risk. The FDA will continue to evaluate the clinical trial results and communicate final conclusions and recommendations once the review is complete.[Ref]
References
1. "Product Information. Belviq (lorcaserin)." Eisai Inc, Teaneck, NJ.
2. US Food and Drug Administration "Safety clinical trial shows possible increased risk of cancer with weightloss medicine Belviq, Belviq XR (lorcaserin) Available from: URL: https://www.fda.gov/media/134174/download." ([2020, Jan 14]):
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.
More about lorcaserin
- During Pregnancy
- Dosage Information
- Drug Interactions
- En Español
- 983 Reviews
- Drug class: anorexiants
- FDA Alerts (2)
Consumer resources
Other brands: Belviq, Belviq XR