Anesthesia Side Effects: The Common, the Rare and How Long They Last

The clip usually runs about forty seconds. Someone surfaces from surgery, still in the recovery bay, and says something gloriously strange about penguins or proposes to the nurse. Millions of people laugh, share it, and then type a quieter question into the search bar: is that normal, and what else does anesthesia do to you? As of March 2026, those videos, plus a wave of social posts claiming that a single operation can “wipe years of memory,” have pushed anesthesia side effects to the top of pre-surgery searches.

The comic footage captures a real phenomenon called emergence, the window when the brain restarts faster than its filters. The memory claim is a different story, and it deserves the evidence rather than the algorithm.

What follows is a sober map of what actually happens after an anesthetic: the effects almost everyone notices, the ones that depend on age or the type of anesthesia, the genuinely rare emergencies, and the timelines for each.

What changed recently in anesthesia care, and why it matters for side effects

Three shifts explain why the conversation feels new even though the drugs are not. The first is fasting. For decades patients were told “nothing after midnight.” Current guidance from anesthesia societies, reflected in NHS and Mayo Clinic patient information, allows clear fluids until roughly two hours before most operations. Arriving less dehydrated appears to reduce post-operative nausea and makes blood pressure easier to manage during the case, although the nausea benefit comes mainly from observational data rather than large randomized trials.

The second shift is the explosion of GLP-1 receptor agonist use, the injectable medicines prescribed for type 2 diabetes and weight management. These slow stomach emptying, which raises the theoretical risk that food is still present when a breathing tube is placed. Since 2023, anesthesia teams in the United States and United Kingdom have added specific questions about these injections to pre-operative checklists. Whether to pause one before surgery is a decision for the prescribing clinician and the anesthesiologist together; patients should never stop a medicine on their own.

The third shift is cultural: phones in recovery bays. Emergence delirium, the brief agitation or disinhibition seen as the anesthetic wears off, has always existed, particularly in children and after certain inhaled agents. It simply was not filmed. Viral exposure has had one useful consequence, which is that more patients now ask their anesthesiologist about it in advance, and more are told the honest answer: it is common, it is harmless, and most people remember none of it.

None of these developments changes the underlying safety profile of modern anesthesia, which the NHS describes as very safe, with serious complications in a small minority of cases. They do change what a well-prepared patient should mention at the pre-operative visit.

What are the most common anesthesia side effects after surgery?

Ask any recovery-room nurse and the list arrives in the same order: nausea, grogginess, sore throat, shivering, muscle aches, and a dry mouth. The Mayo Clinic and Cleveland Clinic list the same cluster, and the reason is mechanical rather than mysterious.

General anesthesia is a reversible, medically induced state of unconsciousness combined with pain control and, usually, muscle relaxation. Achieving it involves several drug classes at once: an intravenous induction agent to send you off, an inhaled or infused agent to keep you there, an opioid for pain, and often a muscle relaxant so a breathing tube can be placed. Each contributes its own aftertaste.

• Nausea and vomiting affect roughly one in four to one in three patients overall, driven by inhaled agents and opioids acting on the brain’s vomiting center.
• Drowsiness and slowed thinking persist for several hours as the drugs redistribute out of brain tissue into fat and muscle.
• Sore throat and hoarseness follow the breathing tube or laryngeal mask; studies report it in somewhere between 20 and 40 percent of intubated patients.
• Shivering happens because anesthetics switch off the body’s normal temperature control and operating rooms are cool.
• Muscle aches are typical after the fast-acting muscle relaxant used for emergency airway placement, which causes brief muscle twitching before relaxation.
• Dry mouth and itching stem from anticholinergic drugs and opioids respectively.

What matters most is that every item on this list is self-limiting. The question is not whether you will feel one of them, because you probably will, but how quickly it fades and which few signs mean something different is happening.

Side effects of general anesthesia: what the first 24 hours usually look like

Picture the day as three overlapping phases rather than a single hangover.

Hours zero to two belong to the recovery unit, formally the post-anesthesia care unit. Oxygen levels, blood pressure and pain are checked every few minutes. This is when shivering, nausea and confusion peak, and when the staff have intravenous access to treat them quickly. Emergence delirium, if it occurs, lives here and rarely lasts beyond 30 minutes.

Hours two to eight are the fog. The induction agent is long gone, but inhaled anesthetics and opioids are still leaving fatty tissue and re-entering the bloodstream in small amounts. Expect fragmented memory, clumsy coordination, a thick tongue and difficulty following a conversation. The NHS advises that for 24 hours after a general anesthetic you should not drive, operate machinery, drink alcohol, sign legal documents or care for small children alone, precisely because judgment lags behind how awake you feel.

Hours eight to twenty-four bring the ordinary complaints: a throat that hurts when swallowing, a bruise at the cannula site, aching muscles, and sometimes a low mood or tearfulness that surprises people. That emotional dip is well recognized and has several plausible contributors, including disrupted sleep, residual drugs and the stress response to surgery itself; it typically lifts within a day or two.

By the next morning, most people having a short day-case procedure feel like themselves, minus the surgical soreness. Longer operations, higher opioid requirements and older age stretch each phase, which is why the surgical team’s discharge instructions, not a generic timeline, should guide the first day home.

How long does anesthesia stay in your system?

The honest answer has two parts: the drugs are mostly gone within a day, and the feeling of being “not quite right” can outlast them.

Modern inhaled agents such as sevoflurane and desflurane are chosen partly because they wash out of the lungs within minutes of being switched off. Intravenous propofol is cleared by the liver quickly enough that patients having short sedations are often awake and talking within 10 to 15 minutes. Opioids and benzodiazepines, the sedatives used to reduce anxiety before induction, linger longer, with meaningful effects for 6 to 24 hours depending on the specific drug, the dose the anesthesiologist judged appropriate, and how well your kidneys and liver clear it.

Fat is the complicating factor. Anesthetic agents dissolve into fatty tissue during a long case and leak back out slowly afterwards, which is why a four-hour operation produces a longer fog than a forty-minute one even with identical drugs. Pharmacology studies describe this as redistribution, and it is the main reason recovery scales with surgery length.

Fatigue is a separate matter. Many people report feeling tired or mentally slow for several days, occasionally a couple of weeks, after major surgery. The evidence here is mostly observational, and it points to the surgery itself, with its inflammation, blood loss, disrupted sleep and pain medicines, rather than the anesthetic drugs alone. One useful way to separate the two: side effects that are clearly drug-related (dry mouth, itching, grogginess) are gone within 24 hours; what remains is recovery from the operation.

Anyone still feeling confused, excessively sleepy or unable to keep fluids down after the first day should contact the surgical team rather than wait it out.

Why nausea and vomiting top the list, and who is most at risk

Post-operative nausea and vomiting, abbreviated PONV, is the single most common reason patients rate their anesthesia experience poorly, and it is also the one with the strongest predictive science behind it.

A validated scoring system, derived from large patient cohorts and confirmed in randomized trials, identifies four independent risk factors: being female, being a non-smoker, having a history of motion sickness or previous PONV, and receiving opioids after surgery. With none of these, the risk sits around 10 percent. With all four, it approaches 80 percent. Younger adults and people having gynecological, ear, abdominal or laparoscopic (keyhole) surgery are also at higher risk.

The mechanism involves the chemoreceptor trigger zone, a patch of brainstem outside the blood-brain barrier that samples the blood for toxins. Inhaled anesthetics and opioids both stimulate it. So does bowel handling during surgery and, less obviously, dehydration and low blood pressure.

This matters because PONV is highly preventable. Randomized trials, including a landmark factorial trial published in 2004 that tested combinations of preventive measures in more than 5,000 patients, showed that each added intervention cuts the remaining risk by roughly a quarter. Anesthesiologists now routinely stack approaches for high-risk patients: anti-nausea medicines given during the case, substituting intravenous propofol for inhaled gas, keeping fluids up, and using regional techniques to spare opioids. The level of evidence for this combined strategy is high; it rests on multiple randomized trials and meta-analyses.

Which medicines, and in what combination, is a clinical decision for the anesthesia team. Your contribution is simpler: tell them if you have ever been sick after an anesthetic or get carsick easily. That history moves you up the risk ladder and changes the plan.

Sore throat, hoarseness, chills and shivering: the airway and temperature effects

Two of the most noticed anesthesia side effects have nothing to do with the drugs’ action on the brain.

The sore throat comes from the airway device. During general anesthesia, breathing is protected either with an endotracheal tube, a plastic tube passed between the vocal cords into the windpipe, or a laryngeal mask, a soft cuff that sits above the voice box. Both press on mucous membranes for the length of the operation. Larger tubes, longer surgeries, head and neck procedures and multiple attempts at placement all increase the chance of a raw throat, hoarse voice or the sensation of something stuck when swallowing. Reviews put the incidence after intubation at roughly 30 to 40 percent, and lower with a laryngeal mask. It usually settles within two to three days. Hoarseness lasting more than a week, or any difficulty breathing, is worth a medical review because it can rarely signal vocal cord injury.

Shivering has a different source. Anesthetics widen blood vessels and switch off the hypothalamus, the brain’s thermostat, so core temperature drifts down toward the temperature of the operating room. When the drugs wear off, the thermostat reactivates and the body shivers to catch up. Hypothermia also slows drug clearance and wound healing, which is why warming blankets and warmed intravenous fluids are standard practice; randomized trials of active warming show fewer wound infections and less shivering. The evidence for warming is strong.

Chills can also signal a fever beginning, and here timing helps. Shivering in the first hour after waking is almost always the thermostat resetting. Chills that start a day or more later, especially with a temperature above 38°C (100.4°F), point toward infection and need assessment.

Spinal anesthesia side effects and other regional blocks

Regional anesthesia numbs one part of the body while you stay awake or lightly sedated. It comes in three main forms: spinal anesthesia, a single injection of local anesthetic into the fluid around the spinal cord; epidural anesthesia, a thin catheter placed just outside that fluid, often used in labor; and peripheral nerve blocks, injections around specific nerves in an arm or leg.

Spinal anesthesia side effects follow from the technique. Because the block switches off nerves that keep blood vessels constricted, blood pressure can drop, producing light-headedness and nausea that the anesthesiologist treats in the moment. Difficulty passing urine is common for several hours because the bladder nerves recover last. A post-dural puncture headache, a positional headache that worsens when upright and eases lying flat, affects about one percent of spinals with modern fine needles; it stems from a slow leak of cerebrospinal fluid and generally resolves within a week, sometimes with a procedure to seal the leak.

Itching is frequent when opioids are added to a spinal or epidural. Back soreness at the injection site lasts a day or two. Temporary tingling or weakness in a leg after a nerve block is expected and should fade as the local anesthetic wears off, usually within 24 hours.

Permanent nerve damage is the fear that keeps people from choosing regional techniques, and the data are reassuring: the NHS cites estimates of serious permanent harm from spinal or epidural anesthesia in the range of 1 in 20,000 to 1 in 50,000. Those figures come from large national audits, which count as good-quality observational evidence.

Red flags after a regional technique are specific: numbness or weakness that worsens rather than improves, new severe back pain, loss of bladder or bowel control, or fever with back pain. Each needs urgent assessment because they can indicate bleeding or infection pressing on nerves.

Anesthesia side effects in elderly adults: delirium, memory and what the data show

The viral claim that anesthesia steals memory has a kernel of truth wrapped in a great deal of exaggeration. The kernel is post-operative delirium and post-operative cognitive dysfunction, two distinct conditions that cluster in older adults.

Post-operative delirium is an acute state of confusion, inattention and fluctuating alertness that typically begins one to three days after surgery. It affects somewhere between 10 and 50 percent of adults over 65 depending on the operation, with hip fracture repair and cardiac surgery at the top. Risk factors are well established from observational cohorts: existing memory impairment, poor hearing or vision, dehydration, infection, sleep deprivation, untreated pain and certain sedating medicines. Delirium is distressing but usually resolves within days to a week.

Post-operative cognitive dysfunction is subtler: measurable difficulty with memory or concentration lasting weeks or months. Early studies suggested it was common, but careful work with proper control groups found that much of the apparent decline reflected normal variation in testing, and that most people return to baseline within three months.

The central question, whether anesthesia causes dementia, has been examined in large population studies and in twin cohorts where one twin had surgery and the other did not. These find no convincing causal link; where associations appear, they are better explained by the underlying illness that led to surgery. That is observational evidence, so it cannot rule out a small effect, but it is consistent and large.

What the evidence does support is prevention. Keeping glasses and hearing aids on, early mobilization, protecting sleep, treating pain adequately and involving family in orientation all reduce delirium in randomized and quasi-randomized studies. Older adults and their families should ask the team specifically about a delirium prevention plan.

The rare but serious: awareness, malignant hyperthermia and severe allergic reactions

Three complications dominate the anxious imagination, and all three are genuinely uncommon.

Accidental awareness means becoming conscious during surgery while intended to be unconscious. Older questionnaire studies suggested rates of 1 to 2 per 1,000. A large national audit across the United Kingdom and Ireland, published in 2014, found that patients spontaneously reported awareness in about 1 in 19,000 general anesthetics, most often during emergency cesarean section or cardiac surgery, and most commonly as brief, dreamlike episodes rather than full consciousness with pain. The highest-risk moment is when muscle relaxants are used, because the usual sign of a light anesthetic, movement, is abolished. Two large randomized trials of brain-wave monitors did not show they outperformed careful monitoring of anesthetic concentration, so the evidence that monitors prevent awareness is mixed.

Malignant hyperthermia is an inherited muscle disorder in which certain inhaled anesthetics and one muscle relaxant trigger runaway muscle metabolism, soaring temperature and acid buildup. It occurs in roughly 1 in 100,000 anesthetics in adults and is treated with a specific antidote kept in every operating suite. The crucial thing to know is that it runs in families: anyone with a relative who had an unexplained severe reaction to anesthesia should say so, because safe alternative drugs exist.

Anaphylaxis, a rapid, whole-body allergic reaction, occurs in approximately 1 in 10,000 to 1 in 20,000 anesthetics. Muscle relaxants, antibiotics given at the start of surgery, latex and chlorhexidine skin preparation are the usual culprits. It is treated immediately in theater, and survivors are referred for allergy testing so future anesthetics can avoid the trigger.

Death attributable purely to anesthesia in a healthy adult is estimated by the NHS at around 1 in 100,000. Each of these figures comes from large registries and audits, which is solid observational evidence.

Side effects by type of anesthesia: a comparison table

Different techniques produce different signatures, which is one reason your anesthesiologist may suggest an option you did not expect. The table summarizes typical patterns; individual experience varies with the operation, age and health.

Type	What it is	Common side effects	Typical duration	Rare but serious
General anesthesia	Full unconsciousness with airway support	Nausea, grogginess, sore throat, shivering, muscle aches, confusion	Hours to 1–2 days	Awareness, malignant hyperthermia, anaphylaxis, aspiration
Spinal	Single injection into spinal fluid	Low blood pressure, urinary retention, itching, back soreness	Hours; headache up to a week	Post-dural puncture headache, nerve injury, bleeding around the spine
Epidural	Catheter outside the spinal fluid	Patchy numbness, itching, low blood pressure, shivering	Hours after catheter removal	Same as spinal; infection at site
Peripheral nerve block	Local anesthetic around a nerve	Prolonged numbness or heaviness in the limb, bruising	8–24 hours, occasionally longer	Persistent nerve symptoms (uncommon, usually temporary)
Sedation (“twilight”)	Intravenous drugs for relaxation and partial amnesia	Drowsiness, memory gaps, nausea, light-headedness	Several hours	Slowed breathing requiring support
Local anesthesia	Injected or applied numbing at the site	Stinging, swelling, temporary numbness	1–4 hours	Toxicity with very large amounts (rare)

A pattern emerges: the deeper the technique reaches into the central nervous system, the broader the side-effect profile but the shorter the numbness afterward. Regional and local techniques trade whole-body effects for localized ones. For many orthopedic, urological and obstetric procedures, combining a regional block with light sedation now delivers the best balance, with less nausea and less opioid use documented in randomized comparisons. The right choice depends on the surgery, your medical history and your preferences, and belongs in a conversation with the anesthesiologist before the day.

What the evidence actually says: grading the claims

Anesthesia is one of the best-studied corners of medicine, but not every popular claim rests on the same foundation. Here is how the main ones stack up.

• Nausea prevention works, and stacking interventions works better. Evidence: multiple large randomized trials and meta-analyses. Grade: high.
• Keeping patients warm reduces shivering and wound infection. Evidence: randomized trials. Grade: high.
• Clear fluids until two hours before surgery are safe. Evidence: randomized trials showing no increase in stomach volume, plus decades of audit data. Grade: high for safety; moderate for nausea benefit.
• Anesthesia causes long-term dementia. Evidence: large observational and twin studies finding no causal link. Grade: moderate evidence against the claim; a small effect cannot be entirely excluded.
• Brain-wave monitors prevent awareness. Evidence: two large randomized trials with conflicting results. Grade: low to moderate; expert opinion favors use in specific high-risk situations.
• Regional anesthesia reduces delirium in older adults. Evidence: a large 2021 randomized trial in hip fracture surgery found no difference between spinal and general anesthesia for delirium or walking recovery. Grade: high, against the earlier assumption.
• A single anesthetic harms young children’s brain development. Evidence: a randomized trial comparing awake-regional with general anesthesia in infants found no difference in IQ at age five; observational cohorts show no effect from one short exposure. Grade: high for single brief exposures; uncertain for repeated or prolonged ones.
• Nitrous oxide raises complication rates. Evidence: a randomized trial of more than 7,000 patients in 2014 found no increase in death or major complications. Grade: high.

The through-line is encouraging. The claims that cause the most fear, lasting cognitive damage in adults and children, have the strongest reassuring data. The practical measures that reduce everyday side effects are also the best proven. Where uncertainty remains, it concerns refinements such as monitoring technology rather than fundamental safety.

Common myths about anesthesia side effects, corrected

Viral claims travel faster than audits. Six that deserve a direct response:

“Anesthesia erased my memory for years.” Brief memory gaps around surgery are universal and expected; the drugs are designed to block memory formation during the procedure. Measurable cognitive change beyond three months is uncommon and, in large studies, not causally linked to the anesthetic itself.

“Redheads need more anesthesia.” This one has a sliver of science. A small study found people with a particular variant of the MC1R gene, common in red-haired individuals, required somewhat more inhaled anesthetic. Later studies have been inconsistent. Anesthesiologists titrate to effect in every patient regardless, so hair color does not change outcomes.

“You can wake up paralyzed and feel everything.” Awareness with paralysis is the rarest form of an already rare event. National audit data put patient-reported awareness at roughly 1 in 19,000, and the majority of episodes involve no pain.

“People say their darkest secrets coming out of anesthesia.” Emergence disinhibition produces nonsense far more often than confessions. The frontal lobe’s filter returns within minutes, and most people recall nothing.

“If you ate, they’ll just do the surgery anyway.” A full stomach raises the risk that acidic contents enter the lungs during induction, a complication called aspiration. Elective surgery is postponed for that reason, not for inconvenience.

“Anesthesia is riskier than the surgery.” For a healthy adult, the risk of death from the anesthetic alone is in the region of 1 in 100,000, far below the risk of most operations themselves. Pre-existing heart or lung disease shifts the balance, which is exactly what pre-operative assessment is for.

The thread connecting these myths is that each takes a real, rare or minor phenomenon and inflates it into the expected experience. The expected experience is a sore throat and a nap.

How to lower your risk before surgery: what patients can actually control

The anesthesiologist controls the drugs. You control the information and the preparation, and both move the odds.

Bring the full list. Prescription medicines, over-the-counter painkillers, supplements and herbal products all matter. St John’s wort, ginkgo, garlic and fish oil capsules can affect bleeding or drug metabolism. GLP-1 injections for diabetes or weight management affect stomach emptying. Blood thinners, diabetes medicines and blood pressure tablets each require a specific plan. The instruction to continue, pause or adjust anything comes from the prescribing clinician and the anesthesia team, never from a website.

Share your history honestly. Previous nausea after anesthesia, motion sickness, a difficult airway, snoring or sleep apnea, a family member with a severe reaction to anesthesia, and alcohol or recreational drug use all change the plan. Cannabis use in particular is associated in observational studies with higher anesthetic requirements and more post-operative pain; it is a clinical detail, not a judgment.

Follow the fasting rules exactly. Modern instructions typically allow clear fluids closer to surgery than older advice, but the specifics vary by hospital and procedure. The written instruction you receive takes precedence.

Stop smoking, even briefly. Quitting several weeks before surgery lowers lung complications and improves wound healing in cohort studies; even 24 hours without cigarettes reduces carbon monoxide in the blood and improves oxygen delivery.

Arrange the first 24 hours. A responsible adult to take you home and stay overnight is a safety requirement after general anesthesia or sedation, not a formality, because judgment and reflexes lag behind alertness.

Ask two questions at the pre-operative visit: what type of anesthesia is planned and why, and what the plan is for nausea and pain. Patients who know the plan report less anxiety, and lower anxiety is itself associated with less post-operative nausea and pain in observational studies.

When to see a doctor: red flags after anesthesia

Most anesthesia side effects fade without any medical input. A short list does not, and recognizing it early makes the difference.

Call emergency services immediately if any of the following occur after discharge:

• Difficulty breathing, noisy breathing, or lips or fingertips turning blue or grey
• Chest pain, a racing or irregular heartbeat, or fainting
• Swelling of the face, lips or tongue, widespread hives, or a sudden feeling of impending collapse (possible delayed allergic reaction)
• Severe confusion, inability to stay awake, or a seizure
• A rapidly rising temperature with rigid or very painful muscles and dark urine within the first day (a rare delayed presentation of malignant hyperthermia)

Contact the surgical team the same day for:

• Vomiting that prevents keeping any fluids down for more than 12 hours, or any vomit containing blood
• A headache after spinal or epidural anesthesia that is severe, worsens when upright, or comes with neck stiffness, fever or vision changes
• Numbness, tingling or weakness in a limb that worsens or has not improved 24 hours after a nerve block or regional anesthetic
• Inability to pass urine for more than 8 hours after a spinal or epidural
• Loss of bladder or bowel control, or new severe back pain after a spinal procedure
• Hoarseness or difficulty swallowing lasting more than a week
• Fever above 38°C (100.4°F) beginning more than 24 hours after surgery

Discuss at follow-up any confusion, memory difficulty or low mood persisting beyond a week, particularly in older adults, and any suspected drug reaction. If anaphylaxis occurred in theater, ask about referral for allergy testing so the trigger can be documented for future anesthetics.

Every decision about medicines, including whether to restart, pause or adjust anything after surgery, rests with the prescribing clinician. The anesthesia team wants to hear about problems, including ones that turn out to be minor; a phone call is never an imposition.

Frequently asked questions

What are the most common side effects of general anesthesia?

Nausea, drowsiness, a sore throat, shivering, muscle aches and a dry mouth are the most frequent. Nausea affects roughly a quarter to a third of patients, and a sore throat follows the breathing tube in up to 40 percent. Temporary confusion and a low mood are also common in the first day. All of these typically resolve within hours to a couple of days without specific treatment.

How long does anesthesia stay in your system after surgery?

The drugs themselves are largely cleared within 24 hours, with modern inhaled agents leaving the body within minutes and intravenous sedatives within hours. Fatigue and mental slowness can persist for days after major surgery, but that reflects the operation, inflammation and disrupted sleep rather than lingering anesthetic. Do not drive, drink alcohol or sign documents for 24 hours after a general anesthetic.

Why do I feel so emotional or tearful after anesthesia?

A brief low mood or tearfulness in the first day or two is well recognized and usually passes on its own. Likely contributors include residual sedative drugs, sleep disruption, pain medicines and the body’s stress response to surgery. The evidence here is mostly observational. If low mood lasts beyond a week or feels severe, mention it to the surgical team or your usual doctor.

Are anesthesia side effects worse in elderly patients?

Older adults are more likely to experience post-operative delirium, an acute confusion that typically begins one to three days after surgery and resolves within a week. Risk rises with existing memory problems, hearing or vision loss, dehydration and certain sedating medicines. Proven prevention includes early mobilization, keeping glasses and hearing aids on, protecting sleep and adequate pain control. Ask the team about a delirium plan.

What are the side effects of spinal anesthesia?

A temporary drop in blood pressure, difficulty passing urine for several hours, itching and back soreness at the injection site are the common ones. About one percent of patients develop a post-dural puncture headache that worsens when upright and usually settles within a week. Worsening numbness, loss of bladder control or severe back pain afterward are red flags that need urgent assessment.

Can anesthesia cause memory loss or dementia?

Memory gaps around the operation itself are expected because anesthetic drugs block memory formation. Lasting cognitive change beyond three months is uncommon, and large population and twin studies have found no convincing causal link between anesthesia and dementia. That is observational evidence, so a small effect cannot be ruled out entirely, but the overall data are consistently reassuring.

Is it true some people wake up during surgery?

Accidental awareness is real but rare. A large UK and Ireland audit found patients spontaneously reported it in about 1 in 19,000 general anesthetics, most often during emergency cesarean section or cardiac surgery. Most episodes are brief and dreamlike rather than painful. Risk is higher when muscle relaxants are used, and anesthesiologists monitor drug concentrations closely to prevent it.

What is malignant hyperthermia and how rare is it?

Malignant hyperthermia is an inherited muscle disorder in which certain inhaled anesthetics and one muscle relaxant trigger a dangerous rise in temperature and metabolism. It occurs in roughly 1 in 100,000 anesthetics and is treated with a specific antidote stocked in every operating suite. Because it runs in families, telling the anesthesiologist about any relative’s severe reaction allows safe alternative drugs to be chosen.

Why does my throat hurt after anesthesia and how long will it last?

The breathing tube or laryngeal mask used to protect your airway presses on the throat lining throughout the operation, causing soreness, hoarseness or a sensation of something stuck when swallowing. It occurs in roughly 30 to 40 percent of intubated patients and usually settles within two to three days. Hoarseness lasting more than a week, or any breathing difficulty, should be reviewed by a doctor.

When should I call a doctor about anesthesia side effects?

Call emergency services for breathing difficulty, chest pain, facial swelling, severe confusion or inability to stay awake. Contact the surgical team the same day for vomiting that prevents keeping fluids down, a worsening headache after a spinal, numbness that is not improving after 24 hours, inability to pass urine, or fever above 38°C beginning more than a day after surgery.

References

• NHS: General anaesthesia
• MedlinePlus: Anesthesia
• Cleveland Clinic: Anesthesia

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.