Based on NIH | Can losartan cause insomnia or other sleep disturbances, and how common is this side effect?

Yes losartan can be associated with insomnia and other sleep disturbances, but these effects appear to be uncommon and were not prominent in large controlled trials. Regulatory product information lists “insomnia,” “sleep disorder,” and related nervous system/psychiatric effects among reported adverse reactions to losartan (including combination products with hydrochlorothiazide), suggesting the effect is possible but not frequent. ^{[1] [2]} In contrast, summaries of double‑blind trials involving roughly 2,900–3,700 participants found adverse event rates similar to placebo overall, with dizziness being the only event more often labeled drug‑related than placebo, and did not highlight insomnia as a common signal. This pattern supports that sleep problems can occur but are likely uncommon. ^{[3] [4]}

What the official labels say

• The U.S. labeling for losartan oral suspension lists “sleep disorders” and “somnolence” among nervous system/psychiatric adverse reactions. This indicates that both trouble sleeping and excessive sleepiness have been reported. ^[1]
• Combination labeling for losartan with hydrochlorothiazide includes “insomnia,” “sleep disorder,” and related symptoms like “nervousness,” “dream abnormality,” and “somnolence,” implying a spectrum of sleep‑related complaints. These listings are based on post‑marketing and clinical experience and mean the events have been observed even if exact frequencies aren’t specified. ^{[5] [2]}

How common is it?

• In pooled, double‑blind, controlled trials of losartan (alone or with hydrochlorothiazide), overall tolerability was similar to placebo, and only dizziness emerged as more commonly considered drug‑related than placebo. Because insomnia was not highlighted among the most frequent adverse events, its occurrence is likely infrequent in clinical trials. ^[3]
• A broader safety review across ~3,700 trial participants also found adverse events comparable to placebo overall, again without signaling insomnia as a common problem. This suggests sleep complaints, while possible, were not among the leading side effects in controlled settings. ^[4]

Possible mechanisms and context

• Animal data have suggested angiotensin receptor blockers might affect melatonin rhythms, but a human study giving losartan 50 mg daily for 7 days found no significant change in the circadian pattern of melatonin secretion, making a melatonin‑mediated mechanism less likely in typical dosing. ^[6]
• Given these findings, when insomnia occurs on losartan, it may reflect idiosyncratic sensitivity, concurrent conditions (e.g., anxiety, sleep apnea), or other medications, rather than a consistent pharmacologic effect on sleep pathways. ^[6]

Practical management tips

• If sleep problems begin after starting or increasing losartan, consider timing the dose earlier in the day. Avoiding bedtime dosing is a common way to minimize medication‑associated insomnia for agents that can cause activation. ^[7]
• If symptoms are mild, they often settle over the first week or two as the body adjusts; if persistent or bothersome, discuss with a clinician about dose adjustment or considering an alternative antihypertensive with a similar benefit profile. ^[3]
• Ensure other contributors to insomnia are addressed (caffeine, alcohol, late‑day exercise, screen time, untreated pain, nasal congestion). When needed, short‑term sleep hygiene strategies or brief use of a sleep aid might be considered, guided by a clinician. ^[7]

---

Quick reference table

Question	Evidence-based answer
Can losartan cause insomnia?	Yes; insomnia/sleep disorders are listed among reported adverse effects in official labeling. [1] [2]
How common is it?	Not clearly quantified, but large controlled trials did not identify insomnia as a common or leading adverse event; overall AE rates were similar to placebo. [3] [4]
Related sleep effects	Sleep disorder, somnolence, dream abnormalities, nervousness have been reported. [5] [1]
Mechanism evidence	Human data show no significant effect of losartan on melatonin circadian rhythm over 7 days, arguing against a consistent melatonin‑mediated mechanism. [6]
What to do if it occurs	Try daytime dosing, optimize sleep hygiene, and consult a clinician if persistent; consider dose change or alternative agent if needed. [7] [3]

---

Bottom line

• Losartan has been associated with insomnia and other sleep disturbances in product information, indicating the effect is possible. However, controlled trials suggest these events are uncommon and overall tolerability is similar to placebo. ^{[1] [2] [3] [4]}
• If you notice new or worsening insomnia after starting losartan, adjusting dose timing and addressing sleep hygiene are reasonable first steps, with medical review if symptoms persist. ^[7]