Levalbuterol

Limits on what this shows

• Null findings: Adults at the lowest labeled dose (0.63 mg): -0.2 mEq/L, identical to placebo -0.2 [1]. Mhanna 2009 [8], retrospective, very low birth weight infants on levalbuterol 0.31 mg vs racemic albuterol 1.25 mg for 2 or more weeks: hypokalemia did not differ between groups (abstract only; the group-to-n mapping in the reconstructed abstract is internally inconsistent, so counts are not quoted). HFA label: “no significant laboratory abnormalities” [2].
• At-risk subgroups: People on non-potassium-sparing diuretics (label 7.3) [1][2]; high or excessive dosing and overdose (label section 10) [1]; people with pre-existing hypokalemia or arrhythmia risk are a clinical inference not stated in the label text read.

Regulatory status

Present in the label. Warning 5.8: the drug “may produce significant hypokalemia in some patients, possibly through intracellular shunting”; “The decrease is usually transient, not requiring supplementation.” Section 10 (overdose) says hypokalemia may occur. Section 7.3: hypokalemia or ECG changes from non-potassium-sparing diuretics “can be acutely worsened by beta-agonists”. The HFA label also advises potassium monitoring with loop or thiazide diuretics but reports no numeric potassium change and “no significant laboratory abnormalities” in its trials [1][2]. Both labels were read through a summarizing fetch tool.

Population evidence

(a) Label table, solution trials, mean change at 1 hour on day 1 [1]. Adults: levalbuterol 0.63 mg -0.2 mEq/L, 1.25 mg -0.3, racemic albuterol 2.5 mg -0.3, placebo -0.2 (arm sizes in the adverse-reaction table were 72 to 75; the laboratory table's own n, SDs and CIs were not in the text read). Children 6 to 11 years: levalbuterol 0.31 mg -0.31, 0.63 mg -0.36, racemic 1.25 mg -0.27, racemic 2.5 mg -0.56, placebo -0.05 (arms of 59 to 67). (b) Handley 2000 [6]: randomized double-blind five-way crossover, n = 20 adults with mild to moderate asthma, placebo, racemic albuterol 2.50 mg, levalbuterol 0.31, 0.63 or 1.25 mg; the lower levalbuterol doses had a smaller effect on potassium than racemic albuterol or high-dose levalbuterol (qualitative in the abstract; no numbers). (c) Pancu 2003 [5]: randomized double-blind placebo-controlled, 9 healthy adults per group, nebulized saline vs albuterol 10 mg vs levalbuterol 2.5 mg, potassium at baseline, 30, 60 and 90 minutes; only levalbuterol produced a significant drop immediately after nebulization, and at 30 and 60 minutes both active drugs lowered potassium vs placebo with no difference between them. Effect size and CI not retrieved (abstract summary only). (d) Shebli 2025 [4]: single-center single-blinded RCT, adults with K above 5.9 mEq/L, all given insulin plus 25 g glucose; levalbuterol 5 mg vs albuterol 10 mg; baseline 6.59 (SD 0.46) vs 6.68 (SD 0.43); change at 90 minutes -0.74 (SD 0.45, n = 15) vs -1.31 (SD 1.19, n = 10), p = 0.176, no CI, as-treated analysis of 30 patients (18 vs 12), underpowered. (e) Andrews 2009 [7]: randomized double-blind, 81 children with status asthmaticus (41 levalbuterol 10 mg/hour, 40 racemic 20 mg/hour, continuous nebulization); potassium and glucose were drawn in the first 40 subjects and the abstract reports “similar changes” with no values.

Mechanism

Named by the label: intracellular shunting of potassium after beta-2 receptor stimulation [1]. The Shebli article attributes the potassium-lowering effect to the (R)-enantiomer acting through the beta-2 receptor [4]. A specific transport step (for example Na+/K+-ATPase) is not stated in any source opened and is not asserted here.

R-enantiomer vs racemic

Levalbuterol arms and racemic albuterol arms sit in the same label trials, so the comparison is direct. At doses the label treats as comparable, the adult effect is the same (-0.3 vs -0.3 mEq/L at 1 hour); in children racemic 2.5 mg gave the largest fall (-0.56) [1]. Pancu found no difference between levalbuterol and albuterol at 30 and 60 minutes [5] and Shebli found none at 90 minutes [4]. The potassium effect therefore tracks the (R)-enantiomer; the (S)-enantiomer is not required for it. Levalbuterol data are the basis of this entry; no racemic-only study is used to set the grade.

Direction

Transient serum lowering by redistribution. This is not a dietary deficiency (Hard Rules 2 and 5). The label states it usually does not need supplementation [1].

Counter-evidence held on record

Counter-evidence and why not red Four levalbuterol human sources agree on direction, and the label names a mechanism, so the count criterion for red is met. It is held at orange because: (1) at the lowest labeled adult dose the change equals placebo; (2) the finding is a short-lived shift, not a body-store deficit, and the label itself says it usually needs no supplementation; (3) the largest magnitude (-0.74 mEq/L) comes from hyperkalemic patients who also received insulin and glucose, with no placebo arm and a small, imbalanced analysis set; (4) the Pancu effect size and the Andrews values were not retrievable. Framing caution This is a short-lived shift of potassium into cells after a dose, not a shortfall in diet. Do not take potassium because of this entry. People on diuretics who use levalbuterol repeatedly or at high dose are the group to discuss with a prescriber (label sections 7.3 and 5.8).

Limits on what this shows

• Null findings: Searches for levalbuterol with magnesium returned only six acute-asthma review articles (magnesium as a treatment), none reporting a magnesium measurement on levalbuterol. No inhaled-albuterol magnesium study was opened.
• At-risk subgroups: Not defined by the sources read.

Regulatory status

Magnesium is not mentioned in the solution or HFA levalbuterol labels read [1][2].

Population evidence

Whyte 1987 [12]: placebo-controlled intravenous infusions of L-adrenaline and of therapeutic salbutamol in 8 normal subjects; plasma magnesium fell significantly with salbutamol (more slowly than with adrenaline) and had not recovered 1 hour after the infusion stopped; potassium also fell and recovered within 30 minutes; insulin and glucose were not significantly changed by the salbutamol infusion vs control. Effect sizes are not in the abstract. Phillips 1980 [11]: 4 healthy men, intravenous salbutamol or rimiterol, dose-related falls in plasma potassium and phosphate with significant hypomagnesaemia and hypocalcaemia (abstract only, no numbers).

Mechanism

Proposed by Whyte: an intracellular shift through beta-adrenergic stimulation, not insulin-mediated [12]. Not demonstrated for inhaled levalbuterol.

Class cohort test

CLASS EXTRAPOLATION. Cohorts received racemic salbutamol (albuterol) by intravenous infusion; levalbuterol was not in either cohort. Both studies are small and use a route and dose far from inhaled therapy. Capped at yellow (Hard Rule 6).

Counter-evidence held on record

Counter-evidence and confounding Healthy volunteers, intravenous route, no inhaled arm. Phillips and Whyte differ on glucose (Phillips reported dose-related rises, Whyte no significant change with salbutamol). Neither tests levalbuterol. Framing caution A short serum shift seen with intravenous racemic salbutamol is not a magnesium deficiency and gives no reason to take magnesium with levalbuterol.

Limits on what this shows

• Null findings: The PubMed query for levalbuterol with phosphate was rate-limited and not completed (see access note); the query albuterol with hypophosphatemia returned one record, an unrelated salmeterol/fluticasone overdose lactic acidosis report. No levalbuterol phosphate measurement was found.
• At-risk subgroups: Not defined.

Regulatory status

Phosphate is not mentioned in the levalbuterol labels read [1][2].

Population evidence

Phillips 1980 [11]: intravenous salbutamol and rimiterol in 4 healthy men; dose-related falls in plasma potassium, phosphate and corticosteroids. Abstract only, read through OpenAlex; no values, no CI.

Mechanism

Not stated in the abstract. Not asserted.

Class cohort test

CLASS EXTRAPOLATION. Cohort of 4 received racemic salbutamol and rimiterol intravenously; levalbuterol absent. Capped at yellow (Hard Rule 6).

Counter-evidence held on record

Counter-evidence and confounding n = 4, intravenous, therapeutic infusion doses, no inhaled data, no replication located. Framing caution A phosphate fall in four volunteers on an infusion is not evidence of phosphate deficiency from inhaled levalbuterol.

Limits on what this shows

• Null findings: No calcium measurement with levalbuterol located; no replication of the calcium result located.
• At-risk subgroups: Not defined.

Regulatory status

Calcium is not mentioned in the levalbuterol labels read [1][2].

Population evidence

Phillips 1980 [11]: significant hypocalcaemia and hypomagnesaemia with dose-related falls in potassium and phosphate, 4 healthy men, intravenous infusions (abstract only; the abstract does not say whether the calcium measure is total or ionized).

Mechanism

Not stated. Not asserted.

Class cohort test

CLASS EXTRAPOLATION. Cohort received racemic salbutamol or rimiterol intravenously; levalbuterol absent. Capped at yellow (Hard Rule 6).

Counter-evidence held on record

Counter-evidence and confounding Single abstract-level source, n = 4, intravenous route; shares its evidence with the magnesium and phosphate entries (see Overlap map). Framing caution Not a calcium deficiency claim and not a reason for calcium supplementation.

Limits on what this shows

• Null findings: Andrews 2009 [7] measured potassium and glucose but its abstract does not mention lactate. PubMed queries for levalbuterol with lactic and with acidosis returned no results.
• At-risk subgroups: Not defined by sources opened. Smith's cases were mostly at labeled doses [13].

Regulatory status

Section 6.2 (postmarketing) of the solution label lists “metabolic acidosis” among reactions reported after approval, with the standard statement that frequency and causality cannot be reliably estimated; the HFA label listing was reported the same way by the fetch tool [1][2]. Section 5.7: large intravenous doses of racemic albuterol “have been reported to aggravate preexisting diabetes mellitus and ketoacidosis.” Lactate is not named in either label [1][2].

Population evidence

Smith 2019 [13]: systematic review of medication-induced hyperlactatemia, 101 reports, 286 patients, 59 medications; epinephrine and albuterol the most common agents; 64.0% hyperlactatemia and 31.1% lactic acidosis; 86% at labeled doses; 16% died (all-drug figures, not albuterol-specific; levalbuterol is not mentioned in the abstract). Meegada 2020 [14]: case report of albuterol-induced type B lactic acidosis that resolved after albuterol was stopped (abstract only). Phillips 1980 [11]: intravenous salbutamol caused significant hyperlactataemia and ketonaemia in 4 healthy men (abstract only).

Mechanism

Meegada frames the event as type B lactic acidosis, meaning altered cellular metabolism without hypoxia or hypoperfusion [14]. A beta-2 mechanism is not spelled out in the abstracts opened and is not asserted.

Class cohort test

CLASS EXTRAPOLATION for the lactate measure. The albuterol cases are racemic albuterol; whether any case in Smith 2019 involved levalbuterol cannot be told from the abstract (full text and case lists not opened). The levalbuterol-specific support is the label's unquantified postmarketing term “metabolic acidosis”, which is not a lactate measurement. Capped at yellow (Hard Rule 6).

Counter-evidence held on record

Counter-evidence and confounding Case reports and spontaneous labeling terms cannot establish rate. Patients treated with repeated nebulization usually have severe asthma, itself a cause of lactate rise (type A), which confounds attribution. No comparator trial measured lactate. Framing caution This is a monitoring prompt about a metabolic effect, not a nutrient deficiency and not a reason to supplement anything.

Limits on what this shows

• Null findings: Mhanna 2009 [8]: hyperglycemia did not differ between levalbuterol and racemic albuterol in very low birth weight infants (abstract only). HFA label: no significant laboratory abnormalities in trials [2].
• At-risk subgroups: People with diabetes mellitus (label caution) [1][2].

Regulatory status

Section 5.7: “Changes in blood glucose may occur”; caution in diabetes mellitus; large intravenous doses of racemic albuterol have been reported to aggravate diabetes and ketoacidosis [1][2].

Population evidence

Label table, solution trials, mean change at 1 hour on day 1 [1]. Adults: levalbuterol 0.63 mg +4.6 mg/dL, 1.25 mg +10.3, racemic albuterol 2.5 mg +8.2, placebo -0.2. Children: levalbuterol 0.31 mg +4.9, 0.63 mg +5.2, racemic 1.25 mg +8.0, racemic 2.5 mg +10.8, placebo +0.6. SDs, CIs and the table's own n were not in the text read. Andrews 2009 [7]: glucose drawn in the first 40 subjects, “similar changes” between levalbuterol and racemic albuterol, no values. Shebli 2025 [4]: glucose measured at baseline only; one hypoglycemia event reported in the albuterol arm (all patients had insulin plus glucose).

Mechanism

Not named in the labels read. A beta-2 metabolic action is plausible but no source opened states it, so it is not asserted.

R-enantiomer vs racemic

Direct label comparison: the racemic 2.5 mg adult arm (+8.2) fell between levalbuterol 0.63 mg (+4.6) and 1.25 mg (+10.3); in children racemic arms were as large or larger than levalbuterol arms [1]. Class studies add little: Phillips 1980 reported dose-related glucose rises with intravenous salbutamol while Whyte 1987 found no significant glucose change with salbutamol [11][12].

Counter-evidence held on record

Counter-evidence and confounding Magnitude is small and short-lived, the data are one label table (a single Tier A source for levalbuterol), and the direction is an increase in a substrate, not a lost nutrient. Held at yellow under Hard Rule 2 even though a drug-specific measurement exists. Framing caution A glucose-monitoring prompt for people with diabetes, not a nutrient claim and not a reason to change diet or supplements.