Clonazepam (Oral Route)

Side Effects

Drug information provided by: Merative, Micromedex®

Along with its needed effects, a medicine 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:

More common

1. Body aches or pain
2. chills
3. cough
4. difficulty breathing
5. discouragement
6. dizziness
7. ear congestion
8. feeling sad or empty
9. fever
10. headache
11. irritability
12. lack of appetite
13. loss of interest or pleasure
14. loss of voice
15. poor coordination
16. runny or stuffy nose
17. shakiness and unsteady walk
18. sleepiness or unusual drowsiness
19. sneezing
20. sore throat
21. tiredness
22. trouble concentrating
23. trouble sleeping
24. unsteadiness, trembling, or other problems with muscle control or coordination
25. unusual tiredness or weakness

Less common

1. Being forgetful
2. bladder pain
3. bloody or cloudy urine
4. change in speech
5. decrease in frequency of urination
6. diarrhea
7. difficulty in passing urine
8. difficult, burning, or painful urination
9. frequent urge to urinate
10. general feeling of discomfort or illness
11. joint pain
12. loss of appetite
13. lower back or side pain
14. mood or mental changes
15. muscle aches and pains
16. nausea
17. nervousness
18. problems in urination or increase in the amount of urine
19. shivering
20. slurred speech
21. sore throat
22. sweating
23. trouble speaking
24. vomiting

Rare

1. Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
2. changes in skin color
3. chest pain, discomfort, or tightness
4. cold sweats
5. colds
6. confusion
7. cough or hoarseness
8. difficulty with sleeping
9. dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
10. excessive dreaming
11. excessive muscle tone
12. excitement
13. falling
14. fast, irregular, pounding, or racing heartbeat or pulse
15. feeling mad
16. feeling of unreality
17. flu-like symptoms
18. headache, severe and throbbing
19. lack of feeling or emotion
20. lack or loss of self-control
21. muscle stiffness, tension, or tightness
22. nightmares
23. pain, inflammation, or swelling in the calves, shoulders, or hands
24. pain or swelling in the arms or legs without any injury
25. pain, tenderness, or swelling of the foot or leg
26. partial or slight paralysis
27. scaling
28. sense of detachment from self or body
29. shakiness in the legs, arms, hands, or feet
30. skin rash
31. swelling around the eyes
32. swelling of the face, ankle, foot, or knees
33. thoughts of killing oneself changes in behavior
34. trembling or shaking of the hands or feet
35. uncaring
36. vision changes

Incidence not known

1. Anxiety
2. black, tarry stools
3. bleeding gums
4. blood in the urine or stools
5. change in consciousness
6. chest congestion
7. difficulty with coordination
8. double vision
9. drowsiness
10. dry mouth
11. feeling that others are watching you or controlling your behavior
12. feeling that others can hear your thoughts
13. feeling, seeing, or hearing things that are not there
14. hyperventilation
15. irregular, fast, slow, or shallow breathing
16. irregular, twisting uncontrolled movement of the face, hands, arms, or legs
17. loss of interest or pleasure
18. loss of memory
19. loss of strength or energy
20. loss of voice
21. muscle weakness
22. pale or blue lips, fingernails, or skin
23. pinpoint red spots on the skin
24. problems with memory
25. restlessness
26. severe mood or mental changes
27. sores, ulcers, or white spots on the lips or in the mouth
28. stomach pain or fullness
29. swollen glands
30. trouble breathing
31. uncontrolled eye movements
32. unusual behavior
33. unusual bleeding or bruising
34. unusual weakness
35. vivid dreams
36. weight loss or gain

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

Symptoms of overdose

1. Agitation
2. change in consciousness
3. changes in patterns and rhythms of speech
4. confusion
5. loss of consciousness
6. loss of strength or energy
7. mood or mental changes
8. nightmares
9. shakiness and unsteady walk
10. sleepiness or unusual drowsiness
11. slurred speech
12. talkativeness
13. trouble speaking
14. unsteadiness, trembling, or other problems with muscle control or coordination
15. unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
16. unusual excitement, nervousness, restlessness, or irritability
17. unusual weak feeling

Some side effects 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:

Less common

1. Decreased interest in sexual intercourse
2. difficulty with swallowing
3. dryness or soreness of the throat
4. heavy bleeding
5. hives
6. inability to have or keep an erection
7. longer than usual time to ejaculation of semen
8. loss in sexual ability, desire, drive, or performance
9. pain or tenderness around the eyes and cheekbones
10. puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
11. voice changes

Rare

1. Acid or sour stomach
2. ankle, knee, or great toe joint pain
3. belching
4. bleeding after defecation
5. blistering, burning, crusting, dryness, or flaking of the skin
6. bloated
7. blurred or loss of vision
8. change in color perception
9. cracks in the skin at the corners of the mouth
10. decrease or change in vision
11. difficulty moving
12. double vision
13. dryness of the eyes
14. earache
15. excess air or gas in stomach or intestines
16. feeling of constant movement of self or surroundings
17. feeling of warmth
18. frequent bowel movements
19. full feeling
20. hair loss or thinning of the hair
21. halos around lights
22. heartburn
23. increased watering of the mouth
24. indigestion
25. irregularities in menstruation
26. itching in the genital or other skin areas
27. itching, scaling, severe redness, soreness, or swelling of the skin
28. joint stiffness or swelling
29. leg or muscle cramps
30. loss of taste
31. night blindness
32. nosebleeds
33. overbright appearance of lights
34. pain in the breasts or pelvic area
35. pain in the leg, nape, or back
36. passing gas
37. red, sore eyes
38. redness of the face, neck, arms, and occasionally, upper chest
39. redness or swelling in the ear
40. sensation of spinning
41. smaller amount of semen ejaculated than usual
42. sore on the edge of the eyelid
43. soreness or redness around the fingernails and toenails
44. stomach discomfort, upset, or pain
45. thickening of the tongue
46. thirst
47. tooth disorder
48. toothache
49. tunnel vision
50. twitching of the eyes
51. uncomfortable swelling around the anus
52. worsening of acne

Incidence not known

1. Burning feeling in the chest or stomach
2. difficulty having a bowel movement (stool)
3. increased appetite
4. increased hair growth, especially on the face
5. increased in sexual ability, desire, drive, or performance
6. increased interest in sexual intercourse
7. sore gums
8. tenderness in the stomach area

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

• Precautions

Portions of this document last updated: Nov. 01, 2023