What are the side effects of Lorazepam (Ativan)?

Lorazepam Side Effects

Lorazepam causes sedation (15.9% of patients), dizziness (6.9%), weakness (4.2%), and unsteadiness (3.4%) as the most common adverse effects, with serious risks including respiratory depression, physical dependence, and paradoxical reactions that require careful monitoring. 1

Most Common Side Effects

The FDA-reported adverse reactions from approximately 3,500 patients treated with lorazepam include:

• Sedation (15.9%) - the most frequent adverse reaction 1
• Dizziness (6.9%) 1
• Weakness/asthenia (4.2%) 1
• Unsteadiness (3.4%) - increases with age 1
• Ataxia and impaired coordination 1, 2
• Drowsiness upon awakening - reported three times more often with lorazepam than triazolam 2

Central Nervous System Effects

• Memory impairment and anterograde amnesia - can occur even with therapeutic doses, particularly after the first dose 1, 3, 4
• Confusion - especially in elderly patients 5
• Headache 1
• Vertigo and lightheadedness 1, 2
• Blurred vision and diplopia 1
• Slurred speech/dysarthria 1
• Extrapyramidal symptoms 1
• Seizures (particularly during withdrawal) 1
• Coma (in overdose or with CNS depressants) 1

Serious and Life-Threatening Effects

Respiratory depression and apnea are critical risks, especially when combined with opioids, alcohol, or other CNS depressants 1. The FDA warns that this combination can cause severe drowsiness, respiratory depression, coma, and death 1.

Physical dependence and withdrawal reactions develop with regular use 1. Abrupt discontinuation causes:

• Rebound insomnia (peaks on third night after withdrawal, often worse than baseline) 5, 3
• Rebound anxiety and tension 5, 3
• Seizures 1
• Hallucinations 1
• Severe mental or nervous system changes 1
• Suicidal thoughts or actions 1
• Prolonged withdrawal symptoms lasting weeks to over 12 months 1

Paradoxical Reactions

Lorazepam can cause paradoxical reactions including 1:

• Anxiety and agitation
• Excitation and hostility
• Aggression and rage
• Sleep disturbances/insomnia
• Hallucinations
• Sexual arousal

Cardiovascular Effects

• Hypotension and small decreases in blood pressure - usually not clinically significant 1
• Orthostatic hypotension 6

Psychiatric and Behavioral Effects

• Increased daytime anxiety and tension with continued use 5
• Depression 1
• Changes in libido 1
• Decreased orgasm and impotence 1
• Delirium and paranoia (with abuse/misuse) 1

Gastrointestinal Effects

• Nausea 1, 2
• Changes in appetite 1
• Constipation 1

Hematologic Effects

• Thrombocytopenia 1
• Agranulocytosis 1
• Pancytopenia 1

Other Notable Effects

• Muscle relaxant effects - particularly problematic after awakening in elderly patients 7
• Worsening of sleep apnea and obstructive pulmonary disease 1
• Hypothermia 1
• SIADH and hyponatremia 1
• Hypersensitivity and anaphylactoid reactions 1
• Alopecia 1

Critical Clinical Considerations

The American Family Physician guidelines emphasize that regular benzodiazepine use leads to tolerance, addiction, depression, and cognitive impairment, with paradoxical agitation occurring in approximately 10% of patients. 6 Infrequent, low doses of agents with short half-lives are least problematic 6.

Elderly patients are at particularly high risk - sedation and unsteadiness increase with age 1, and muscle relaxant effects after awakening are more pronounced 7.

Withdrawal insomnia can be severe - studies show peak withdrawal sleep disturbance is several times greater than the peak sleep improvement achieved during drug administration 5. Delayed but prolonged insomnia can occur even after stopping lorazepam 7.

Abuse and Addiction Risk

Lorazepam is a Schedule IV controlled substance with significant potential for abuse, misuse, and addiction 1. Serious side effects from abuse include coma, death, delirium, paranoia, suicidal thoughts, seizures, and difficulty breathing 1.

Duration of Safety

The FDA notes that safety and effectiveness beyond 4 months of use has not been established. 1