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Medications & the Nervous System

Many medications act on the autonomic nervous system — the part that steers heartbeat, blood pressure, digestion and recovery, and that in Long COVID, ME/CFS and POTS is often out of step. Here you'll read what each medication does in the nervous system, which symptoms it has been observed to affect, and how well that is backed by evidence — honestly sorted by strength of the evidence. This is knowledge for the conversation with your doctor, not a recommendation and not a dosing guide.

Illustration: eine Medikamenten-Box mit Wochenfächern neben einer Tasse Tee auf dem Küchentisch

You want certainty — and that's exactly why we're being honest here

The wish for certainty is more than understandable. When you feel awful, you want to know: What will definitely help me? We'd love to give you that certainty. But it would be dishonest — and in this illness even dangerous — to pretend it already exists. What we do instead: mark every statement with its strength of evidence, so that you and your doctor can decide on the best possible basis.

Why there is no absolute certainty (yet):

That's a property of today's science, not a failing. Honest uncertainty is worth more than false certainty — it protects you from disappointment and from harm.

Important — please read this first. mypacing is not a medical device and gives no treatment recommendation. In Long COVID/ME-CFS almost everything here is off-label (outside the approved use) and partly experimental. Never start or stop a medication because of this page. Dosages, drug interactions and contraindications belong in a doctor's hands — the principle is usually "start low, go slow," with monitoring of pulse, blood pressure and blood values. For PEM (worsening of your condition after exertion) the guideline says: no "pushing through," no graded exercise therapy — but pacing within your own energy limits instead. [1]
controlled trial small study observation / off-label preliminary may worsen symptoms

Heart rate & tachycardia

When the heart "races" on standing or at rest — the most common hallmark of POTS.

Ivabradine (Procoralan) · pacemaker-channel blocker

controlled trial (small)
Effect on the nervous system
Selectively blocks the "funny current" (If) in the sinus node, the heart's natural pacemaker. This lowers the pulse without lowering blood pressure and without acting directly on the sympathetic system (the stress nerves). That's exactly what makes it attractive in POTS, where blood pressure is often already low. [3][4]
Observed effect on symptoms
Less racing heart on standing and at rest, fewer palpitations; in studies, better quality of life and capacity for exertion.
How good is the evidence?
The only drug on this list with a clean (if small) positive result in a double-blind, placebo-controlled trial (n = 22, hyperadrenergic POTS). [3] Observational data show ~74 % response. [5] Still off-label; large long-term studies are lacking.
Things to watch
Not for a resting pulse below 60 or very low blood pressure; can promote atrial fibrillation; harmless flashes of light (phosphenes) in ~3 %; not during pregnancy; serious interaction with certain antibiotics/antifungals (CYP3A4). [4]

Sources: [3] [4] [5]

Beta-blockers low-dose (propranolol, bisoprolol, metoprolol)

controlled trials / guideline
Effect on the nervous system
Dampen the drive of the stress nerves (sympathetic system) at the heart by blocking β-adrenoceptors → slower pulse, fewer adrenaline surges. Propranolol (non-selective) additionally has a mild vessel-narrowing effect.
Observed effect on symptoms
Less racing heart, palpitations, trembling and "wired-up" surges — dose-dependent.
How good is the evidence?
A standard with guideline backing: low-dose propranolol (~10–20 mg) lowers the pulse and improves symptoms; higher doses add no more benefit but do cause more tiredness. [6] Bisoprolol/metoprolol are widely used but less specifically studied in POTS.
Things to watch
In some people can lower blood pressure and worsen tiredness/orthostasis; caution with asthma and a low pulse; do not stop abruptly (rebound). [12]

Sources: [6] [12]

Pyridostigmine (Mestinon) · cholinesterase inhibitor

small studies (mixed)
Effect on the nervous system
Raises the messenger acetylcholine at the autonomic relay points. This strengthens the vagus (the rest nerve) — lowers the pulse — and improves the switching at the ganglia, so that on standing the circulation returns more blood to the heart, without driving up blood pressure while lying down. [7][8]
Observed effect on symptoms
Less standing tachycardia; in ME/CFS, one study showed a small improvement in capacity for exertion; often improves a sluggish gut.
How good is the evidence?
Mixed. POTS: acutely lowers the standing pulse [8], but on average only ~51 % response and no added benefit over a beta-blocker. [5] ME/CFS: randomised, but only a single dose — peak oxygen uptake +~4 % via better return flow; long-term effect unknown. [7]
Things to watch
Cholinergic side effects: abdominal cramps, diarrhoea, nausea, salivation/sweating, muscle twitching; not with bowel/urinary obstruction.

Sources: [7] [8] [5]

Circulation & orthostasis

When the blood "pools" on standing up and the circulation can't keep up.

Midodrine · α1-agonist (vasoconstrictor)

controlled trials (short-term)
Effect on the nervous system
Directly stimulates the α1 receptors on arteries and veins → vessels narrow, less blood pools in the legs, more returns to the heart. In a sense it replaces the missing vessel tension of the sympathetic system; it does not act in the brain.
Observed effect on symptoms
Less dizziness/light-headedness on standing, better standing tolerance; indirectly less reflex tachycardia.
How good is the evidence?
In the short term one of the better-evidenced POTS drugs (in the review, the highest short-term response ~78 %), but the benefit faded beyond about 6 months. [5] Approved for orthostatic hypotension; off-label in POTS.
Things to watch
High blood pressure while lying down — do not take shortly before lying down; tingling/goosebumps on the scalp, urinary urgency; short duration of action (every ~4 h). [12]

Sources: [5] [12]

Fludrocortisone · mineralocorticoid (volume)

traditional, thin evidence
Effect on the nervous system
Acts on the kidney: retains salt and water, increases blood volume — the foundation the overwhelmed circulatory reflexes need. It also makes the vessels more sensitive to the body's own adrenaline. Usually combined with more salt + drinking.
Observed effect on symptoms
Less orthostatic dizziness, better standing tolerance.
How good is the evidence?
Widely used and listed as an option in guidelines, but the evidence is thin — the review found no positive controlled trial and does not rate it as a first choice. [5] Honestly: often tried, weakly evidenced.
Things to watch
Potassium in the blood can drop (monitor it); fluid retention, headaches, high blood pressure when lying down; caution with heart/kidney disease.

Sources: [5] [12]

Desmopressin (DDAVP) · vasopressin analogue

off-label, thin evidence
Effect on the nervous system
Synthetic analogue of the hormone vasopressin: acts on the kidney to retain water, thereby increasing blood volume in the short term — a similar underlying principle to fludrocortisone, but via a different mechanism (no salt retention). No direct effect on the sympathetic/vagal system.
Observed effect on symptoms
In a randomised cross-over trial (n=30), a single dose (0.2 mg) significantly lowered the standing heart rate (109 → 102/min) and improved symptom burden in the short term. [23]
How good is the evidence?
So far only studied as an acute single dose in one small trial [23]; not approved for POTS, used off-label. The authors themselves note that the safety profile with repeated/long-term use would still need to be examined before a routine recommendation is possible — long-term data are lacking.
Things to watch
As with any vasopressin analogue, there is a hyponatremia risk (water retention dilutes blood sodium) — a well-documented, class-wide side effect of desmopressin that requires regular monitoring of serum sodium, especially with concurrent high fluid intake. Note on sourcing: an earlier internal draft of this text cited a specific hyponatremia frequency from a retrospective study; on verification that figure could not be confirmed in the available sources and was therefore removed rather than left unsubstantiated.

Sources: [23]

Nervous system & inflammation

Approaches against exhaustion, "brain fog" and suspected neuroinflammation. The mechanisms here are still uncertain.

Low-dose naltrexone (LDN) · very-low-dose opioid antagonist

preliminary (low–moderate)
Effect on the nervous system
At a very low dose (far below the addiction-medicine dose) it probably works as an immune/glia modulator: via the TLR4 switch on microglia it dampens the release of inflammation-promoting messengers and briefly raises the body's own endorphins. Any benefit to the autonomic nervous system would be indirect — through less neuroinflammation, not through direct access to the sympathetic system/vagus.
Observed effect on symptoms
Exhaustion, "brain fog," headache, sleep, pain — improved in responders.
How good is the evidence?
Preliminary. A 2025 review (Long COVID) found statistically significant but modest improvements at low to moderate evidence quality, and stresses: large randomised trials are still lacking. [9]
Things to watch
Usually well tolerated (vivid dreams, headache at first); blocks opioid painkillers — not together with ongoing opioid therapy; needs a pharmacy that compounds the low dose.

Source: [9]

Low-dose aripiprazole (LDA) · very-low-dose, off-label

preliminary (observation only)
Effect on the nervous system
At a tiny dose (a fraction of the psychiatric dose) it is thought to dampen inflammatory signalling pathways via the dopamine system and to modulate control in the diencephalon (a deep relay region of the brain). The exact mechanism in ME/CFS is unproven.
Observed effect on symptoms
In responders, less exhaustion, a clearer head, more restful sleep.
How good is the evidence?
Weak — so far only a retrospective analysis without a control group (n = 101, Stanford): improvement in fatigue, brain fog, sleep, but a clear non-responder group. No randomised trial. "Promising, but preliminary." [10]
Things to watch
Possible even at a low dose: inner restlessness/akathisia, sleep disturbance, nausea; a psychotropic drug — needs experienced medical supervision.

Source: [10]

Methylphenidate (Ritalin, etc.) · stimulant, off-label

raises pulse/blood pressure — caution in POTS/PEM
Effect on the nervous system
Blocks the reuptake of dopamine and noradrenaline → more wakefulness, concentration and drive. Unlike LDN/LDA above, the approach here is purely symptomatic (more arousal/wakefulness) and is not intended to be anti-inflammatory — it does not resolve the exhaustion, it masks it for a while.
Observed effect on symptoms
In small case series for Long-COVID "brain fog", rapidly improved concentration and subjectively less exhaustion.
How good is the evidence?
Very weak specifically for Long COVID/ME-CFS: so far only one uncontrolled case series of 4 people (Long-COVID brain fog), described by the authors themselves as preliminary — with no control group and no systematically collected safety data. [21] For comparison: in cancer-related fatigue — a different patient population — meta-analyses show a modest benefit; this cannot be directly transferred to ME/CFS or Long COVID.
Things to watch
Stimulants raise pulse and blood pressure — in POTS or hyperadrenergic dysautonomia potentially the opposite of the treatment goal (see damping the sympathetic system above). There is a real risk of merely masking exhaustion and thereby fuelling the push-crash cycle instead of supporting pacing. In Germany it is a controlled substance requiring a special prescription (BtM, Schedule III). Further side effects: loss of appetite, sleep disturbance, palpitations; not with uncontrolled high blood pressure, heart-rhythm disorders or structural heart disease.

Sources: [21] [22]

Histamine & mast cells

When there are signs of mast-cell activation (MCAS) — flushing, racing heart, gut and skin symptoms.

Not the same thing: MCAS and histamine intolerance (HIT). Both present with overlapping symptoms (flushing, racing heart, gut complaints), but they are different mechanisms. MCAS is based on mast cells inappropriately releasing a whole range of mediators (not only histamine) too often or too strongly — usually independent of what was eaten. HIT, by contrast, is considered an imbalance between ingested/produced histamine and its breakdown, mainly via the enzyme diamine oxidase (DAO) — symptoms are typically closely tied to histamine-rich food (e.g. aged cheese, red wine, sauerkraut). The triggers, the diagnostics (tryptase/mediators for MCAS vs. DAO activity/food diary for HIT) and in part the treatment differ accordingly; confusing the two can lead to the wrong dietary advice. A reliable distinction belongs in specialist hands.

Antihistamines H1 + H2 (e.g. loratadine/cetirizine + famotidine)

small RCT signal
Effect on the nervous system
Block the histamine receptors H1 and H2. Because histamine released from mast cells widens vessels and triggers reflex racing of the heart, dampening these messengers can indirectly ease some circulatory and flushing symptoms. No direct action on the sympathetic system/vagus.
Observed effect on symptoms
Flushing, hives, gut complaints, palpitations in MCAS; fatigue (a small, short-lived signal in Long COVID).
How good is the evidence?
Low, but with a recent study signal: in the STIMULATE-ICP trial (~800 people with Long COVID), famotidine+loratadine produced a small, short-term improvement in fatigue that did not last to week 24. [11] Otherwise MCAS treatment rests mainly on experience.
Things to watch
Usually well tolerated/over-the-counter; avoid the old, sedating H1 drugs (they worsen fatigue/brain fog); H2 blockers lower stomach acid (long term, watch B12/absorption).

Source: [11]

Damping the sympathetic system

For the "hyperadrenergic" pattern: high noradrenaline, wired-up on the inside, blood-pressure spikes.

Clonidine · guanfacine · methyldopa · central α2-agonists

small / experience
Effect on the nervous system
Act centrally: they throttle the output of the stress nerves and lower the release of noradrenaline → a calmer pulse, lower blood pressure, fewer adrenaline surges. This is the counter-lever to midodrine — here the sympathetic system is dampened, not replaced.
Observed effect on symptoms
Fewer surges, palpitations, blood-pressure spikes, sweating; sometimes better sleep.
How good is the evidence?
Weak — small studies and experience in beta-blocker-resistant cases; for guanfacine there is more recent supporting data. [13] Under specialist supervision, no large studies.
Things to watch
Can cause strong tiredness/drowsiness and lower blood pressure too far — often poorly tolerated by people who are already exhausted; do not stop clonidine abruptly (rebound blood pressure). [12]

Sources: [13] [12]

Antidepressants & sleep modulation

For accompanying depression, anxiety, pain or unrefreshing sleep — with a double-edged effect on the autonomic system.

SSRIs & SNRIs (e.g. sertraline; venlafaxine, duloxetine)

double-edged — caution in POTS
Effect on the nervous system
In the brainstem, serotonin influences the control of blood pressure and pulse. SNRIs additionally raise noradrenaline — this increases pulse and blood pressure: it can help with low blood pressure, but in POTS it can worsen the racing heart.
Observed effect on symptoms
Mood, anxiety, pain, sleep; on the autonomic side, better or worse depending on the drug and the subgroup.
How good is the evidence?
Weak for an autonomic benefit; used mainly for accompanying conditions. SNRIs are rather avoided in POTS (the specialist society: rather not), since noradrenergic drugs can measurably worsen standing tachycardia. [12]
Things to watch
At first restlessness/racing heart, sweating; discontinuation syndrome (especially venlafaxine); interactions (serotonin syndrome). Weigh the benefit against the autonomic downside.

Sources: [12] [5]

Tricyclic antidepressants, low-dose (amitriptyline, trimipramine)

can lower blood pressure on standing
Effect on the nervous system
At a very low dose (10–25 mg, far below the 150–300 mg dose used for depression) it is mainly the strong antihistamine (H1) and anticholinergic (M1) blockade that promotes sleep and dampens pain processing; inhibition of serotonin/noradrenaline reuptake also contributes to pain relief. The alpha-adrenergic blockade is at the same time vasodilating — the reason for the blood-pressure caution below.
Observed effect on symptoms
Used mainly against unrefreshing sleep and pain sensitivity (overlap with fibromyalgia).
How good is the evidence?
A Cochrane review of amitriptyline in fibromyalgia (2015, 9 trials, 649 people) found ≥50 % pain relief in a minority (NNT 4.1) — but no consistent difference from placebo for fatigue, sleep quality or quality of life, and rated the entire evidence base as very low quality. [18] Despite decades of use: "no unbiased evidence" for a benefit. For trimipramine the study base is even thinner; its assessment here rests mainly on the similar receptor profile.
Things to watch
High rate of side effects (78 % vs. 47 % on placebo in the trial data, NNH 3.3): dry mouth, constipation, urinary retention, weight gain. Can lower blood pressure on standing (alpha blockade) — weigh up with your doctor if you have POTS/a tendency to orthostatic issues; QTc prolongation is possible, caution with heart-rhythm disorders; do not stop abruptly. [19]

Sources: [18] [19]

Mirtazapine · low-dose, NaSSA

controlled trial — no benefit for fatigue
Effect on the nervous system
A "noradrenergic and specific serotonergic" antidepressant (NaSSA): blocks alpha2 autoreceptors (more noradrenaline/serotonin release) while also strongly blocking histamine (H1) and 5-HT2/5-HT3 receptors. Notably, at a low dose (7.5–15 mg) the sedating H1 effect often dominates more than at a higher dose, because the counteracting noradrenergic activation is weaker — which is why low-dose mirtazapine is used specifically for sleep and appetite, not as a classic antidepressant.
Observed effect on symptoms
Unrefreshing sleep, loss of appetite/weight loss (relevant especially in severe illness), sometimes nausea (5-HT3 blockade has an antiemetic effect).
How good is the evidence?
In a randomised, placebo-controlled trial specifically on chronic fatigue/neurasthenia (n = 72), mirtazapine as monotherapy showed no significant advantage over placebo for fatigue after 12 weeks (p = 0.34); an effect appeared only in the sequence "behavioural therapy first, then mirtazapine". [20] Its widespread use therefore rests mainly on the sleep/appetite side effects — not on a proven fatigue benefit.
Things to watch
Sedation/morning "hangover", weight gain (wanted or unwanted depending on the situation); rare but serious: agranulocytosis — get a blood count checked immediately in case of fever or sore throat; do not stop abruptly.

Source: [20]

Complementary & non-drug

Alpha-lipoic acid · antioxidant / prescribable for diabetes

evidence only for diabetic neuropathy
Effect on the nervous system
An antioxidant in the mitochondria; thought to protect autonomic and peripheral nerves from oxidative stress — a plausible but indirect route.
How good is the evidence?
Backed by randomised evidence only for diabetic nerve/autonomic damage [17]. For Long COVID, ME/CFS or POTS there is practically no direct evidence — transferring it is pure assumption.
Things to watch
Usually well tolerated; can lower blood sugar (caution with diabetes medications).

Source: [17]

The best-rated thing is non-drug

In the real-world feedback of thousands of affected people, three things come out best — with the lowest risk: [14]

Discuss with your doctor: what can worsen symptoms

A review checklist — not a call to stop anything

These drugs often lower blood pressure/volume or drive the pulse up — frequently a reason to review together with your doctor. Don't change any of this on your own. [15][16]

And: even "treatment" drugs like beta-blockers, ivabradine or pyridostigmine worsened symptoms in 17–21 % of affected people — another reason for an individual medical weighing-up. [14]

Knowledge is half the reassurance — your data is the other half.

mypacing shows you in black and white how your body responds to exertion, rest — and to changes in your medication. Not as proof, but as an honest observation for your next talk with your doctor.

See insights — what helped others Join for free

Sources

  1. NICE guideline NG206 on ME/CFS (among other things, no curative therapy; pacing instead of graded exercise therapy). nice.org.uk/guidance/ng206
  2. Systematic review of randomised POTS trials (2025). pubmed.ncbi.nlm.nih.gov/40653179
  3. Taub et al., randomised ivabradine trial in hyperadrenergic POTS (2021). pubmed.ncbi.nlm.nih.gov/33602468
  4. Ivabradine — StatPearls (mechanism, contraindications, interactions). ncbi.nlm.nih.gov/books/NBK507783
  5. Oral medications in POTS — systematic review (Frontiers in Neurology, 2024). frontiersin.org … fneur.2024.1515486
  6. Raj et al., propranolol lowers tachycardia and improves symptoms in POTS (Circulation, 2009). ahajournals.org … 108.846501
  7. Systrom et al., pyridostigmine study on exercise intolerance in ME/CFS (CHEST, 2022). omf.ngo … Pyridostigmin (PDF)
  8. Raj et al., acetylcholinesterase inhibition improves tachycardia in POTS (Circulation, 2005). ahajournals.org … 104.497594
  9. Low-dose naltrexone in Long COVID — systematic review & meta-analysis (COVID/MDPI, 2025). mdpi.com/2673-8112/5/12/198
  10. Crosby et al., low-dose aripiprazole in ME/CFS — retrospective (2021). pubmed.ncbi.nlm.nih.gov/33536023
  11. STIMULATE-ICP: famotidine+loratadine in Long COVID (summary, CIDRAP; Lancet Infect Dis 2026). cidrap.umn.edu … long-covid-fatigue
  12. Wells/Elliott et al., pharmacotherapy in POTS — review (Autonomic Neuroscience, 2018). autonomicneuroscience.com … S1566-0702(18)30025-0
  13. Guanfacine in hyperadrenergic POTS (Hypertension, AHA, 2024/25). ahajournals.org … HYPERTENSIONAHA.124.23035
  14. Self-reported treatment experiences in ME/CFS & Long COVID (medRxiv, 2024). medrxiv.org … 2024.11.27.24317656 (PDF)
  15. DINET — "POTS: What to Avoid" (drugs/substances that worsen POTS). dinet.org … pots-what-to-avoid
  16. Autoimmunity & POTS — diagnosis/management (Cleveland Clinic J Med, 2023). ccjm.org/content/90/7/439
  17. Alpha-lipoic acid in diabetic peripheral & autonomic neuropathy (Diabetes/ADA, 1997). pubmed.ncbi.nlm.nih.gov/9285502
  18. Amitriptyline for fibromyalgia in adults — Cochrane review (2015). cochrane.org/evidence/CD011824
  19. Amitriptyline — StatPearls (mechanism, cardiovascular contraindications). ncbi.nlm.nih.gov/books/NBK537225
  20. Cognitive-behavioural therapy vs. mirtazapine for chronic fatigue/neurasthenia — randomised, placebo-controlled trial (British Journal of Psychiatry). cambridge.org … cbt-v-mirtazapine
  21. Methylphenidate in Long-COVID "brain fog" — case series (2025). journals.sagepub.com/doi/10.1177/02537176231222572
  22. Psychostimulants for cancer-related fatigue — systematic review & meta-analysis, for comparison in a different patient population (Journal of Pain and Symptom Management, 2010). jpsmjournal.com … S0885-3924(10)01023-7
  23. Coffin et al., desmopressin acutely improves tachycardia and symptoms in POTS — randomised cross-over trial, n=30 (Heart Rhythm, 2012). pubmed.ncbi.nlm.nih.gov/22561596
mypacing is not a medical device and makes no diagnosis. This page is a general, source-based knowledge base — not a treatment recommendation, not a dosing guide and no substitute for medical advice. Almost all of the uses named here are off-label in Long COVID/ME-CFS. You make decisions about medications together with your doctor. In an emergency: 112. · As of July 2026 · © 2026 mypacing · Stay at your own pace. mypacing is a trademark application on file with the German Patent and Trade Mark Office (DPMA), Ref. No. 302026242304.3.