Isotretinoin, a vitamin A derivative, is most commonly administered to treat severe, resistant acne. It targets and improves all of acne's major pathophysiological variables, such as inflammation, follicular hyperkeratinization, sebaceous gland hyperactivity, and Propionibacterium acnes colonization.6

Isotretinoin induces apoptosis in sebocytes, which is enhanced by the apoptotic proteins tumor necrosis factor-related apoptosis inducing ligand (TRAIL) and neutrophil gelatinase-associated lipoprotein. Reducing pro-inflammatory cytokines such as TNF-α, IL-4, IL-17, and interferon-γ helps reduce acne inflammation. It also alters the immune response by decreasing Th17 development while increasing regulatory T-cell activity.7,8

Isotretinoin is a lipophilic compound with a large distribution volume in adipose tissue. 99.9% of the drug binds to plasma proteins, primarily albumin. When taken with a high-fat meal, its bioavailability improves. The cytochrome P450 enzymes CYP2C8, CYP2C9, CYP3A4, and CYP2B6 are primarily responsible for the drug's hepatic metabolism, which results in both active and inactive metabolites such as 4-oxo-isotretinoin, retinoic acid, and 4-oxo-retinoic acid. Urine and feces are the pathways by which these metabolites are conjugated and removed.9

Isotretinoin is associated with a number of negative side effects. In one study, 94% of participants identified cheilitis as the most common side effect. In terms of metabolism, it usually reduces high-density lipoprotein (HDL) while raising total cholesterol, low-density lipoprotein (LDL), and serum triglycerides.4,10

Up to 11% of patients develop transient elevations in liver transaminases due to hepatic effects. Even though these increases are often moderate and self-limiting, they should be observed if they persist or worsen, as they may suggest underlying liver pathology.9

Although less frequently documented, cardiovascular adverse effects can have a significant clinical impact. Cases of sinus tachycardia have been documented to include atrial tachycardia, pericardial effusion, and temporary right bundle branch block. These findings emphasize the importance of cardiac surveillance in patients with pre-existing heart problems, despite their rarity.5 Please refer to Table 13–8 for a summarized profile of isotretinoin.

Metabolically, isotretinoin therapy has been shown to significantly increase total cholesterol and triglyceride levels, which are established risk factors for atherosclerosis and cardiovascular disease.11 A study reported significant elevations in these lipid parameters during isotretinoin treatment, although no significant changes were observed in plasma phospholipids or red cell membrane fatty acid composition.12,13

Direct cardiac implications have been observed in isolated cases.14 For instance, a case report detailed a 16-year-old boy who developed atrial tachycardia during isotretinoin therapy, with symptoms resolving upon discontinuation of the drug. Another study documented a 33-year-old woman experiencing premature ventricular contractions (PVCs) associated with isotretinoin use, which subsided after stopping the medication. Furthermore, a rare but severe case involved an 18-year-old male developing dilated cardiomyopathy and renal infarction after five months of isotretinoin therapy, with no other identifiable causes.5,14,15

Regarding the autonomic nervous system, isotretinoin may influence sympathetic activity. A study assessing sympathetic skin response (SSR) and electrocardiographic (ECG) parameters in patients undergoing isotretinoin treatment found increased sympathetic activity after one month of therapy, as indicated by changes in SSR, though no significant cardiac side effects were observed in ECG findings. This suggests that isotretinoin may transiently enhance sympathetic nervous system activity without causing overt cardiac dysfunction.13

Despite these reports, larger-scale studies have not demonstrated a significant association between isotretinoin use and increased cardiovascular risk.16 A population-based retrospective cohort study involving over 12,000 adults found no significant increase in cardiovascular events, including myocardial infarction, heart failure, or arrhythmias, among isotretinoin users compared to non-users.17 Similarly, a case-crossover study analyzing data from over 30,000 isotretinoin users did not find a statistically significant association between the drug and cardiovascular, cerebrovascular, or thromboembolic events.14,16 Please refer to Table 2 for a summarized overview of all the mentioned studies.

The possible effects of isotretinoin on cardiac electrophysiology have been meticulously researched, especially with regard to ECG measures like the QT interval, heart rate variability (HRV), T-wave abnormalities, and the risk of bradyarrhythmias in pediatric patients.

The time between the beginning of ventricular depolarization and the conclusion of repolarization is represented by the QT interval on an ECG. Clinically significant, prolonged corrected QT interval (QTc) can put people at risk for potentially fatal arrhythmias such as torsades de pointes. Adults normally have QTc values of less than 440 ms; values greater than 450 ms for males and 470 ms for females are regarded as prolonged.18

A study by Dursun et al. investigated the effects of isotretinoin on QT intervals and QT dispersion in 45 patients with severe acne undergoing six months of therapy at a dose of 0.8 mg/kg/day. The results demonstrated no significant changes in QT intervals or QT dispersion throughout the treatment period, suggesting that isotretinoin does not adversely affect these ECG parameters.19

Regarding HRV, which reflects autonomic nervous system activity and is an indicator of cardiac health, a study assessing sympathetic skin response (SSR) and ECG parameters in patients undergoing isotretinoin treatment found increased sympathetic activity after one month of therapy, as indicated by changes in SSR. However, no significant cardiac side effects were observed in ECG findings, indicating that while isotretinoin may transiently enhance sympathetic nervous system activity, it does not cause overt cardiac dysfunction. T-wave abnormalities, which can indicate repolarization disturbances, have not been consistently associated with isotretinoin therapy. While isolated case reports have documented arrhythmic events such as premature ventricular contractions (PVCs) and atrial tachycardia during isotretinoin use, these instances are rare and often resolve upon discontinuation of the drug.5

Therefore, current research indicates that isotretinoin medication does not significantly influence important ECG measures such as the QT interval, heart rate variability (HRV), or T-wave morphology in young patients, despite the fact that it may have an effect on some elements of autonomic function. Although large cohort studies generally report no significant ECG changes or increase in major cardiovascular events with isotretinoin, isolated case reports and small observational studies have documented arrhythmias and autonomic alterations. This discrepancy highlights the importance of vigilance, particularly in younger patients who may be more susceptible to drug-induced electrophysiological changes.

Kindly refer to Table 3 for a tabulated summary of ECG parameters in patients undergoing isotretinoin therapy.

Isotretinoin has been linked to slight but important cardiac electrophysiological changes. To understand these effects, the existing evidence can be separated into two categories: preclinical (experimental) data and human clinical findings. Preclinical research, primarily using embryonic or cellular models, suggests that probable mechanisms include direct impacts on cardiac ion channels, particularly human hERG potassium channels, and interference with myocardial development. Human clinical evidence, on the other hand, emphasizes metabolic and autonomic pathways such as dyslipidemia, electrolyte imbalances, and transitory sympathetic overactivity, all of which may have an indirect effect on cardiac conduction and ECG parameters. Although arrhythmias are rare, studies have explored different biological reasons that might explain changes seen on ECGs during treatment, as seen in Fig. 1.

Figure 1.

Influence of Isotretinoin on cardiac electrophysiology and ECG parameters. CV, Cardiovascular; ECG, Electrocardiogram; HDL, High-density lipoprotein; HR, Heart rate; HRV, Heart rate variability; Herg, human ether-à-go-go-related Gene; K, Potassium; LDL, Low-density lipoprotein; LQTS, Long QT syndrome; Mg, Magnesium; P, Phosphorus; PVCs, Premature ventricular contractions; Zn, Zinc.

More frequent laboratory monitoring may be necessary for patients with higher body weight, as studies have shown that these individuals are at increased risk of developing laboratory abnormalities during isotretinoin therapy, including elevated lipid levels and liver enzyme disturbances.25 This increased susceptibility may be due to differences in drug distribution, metabolism, or underlying metabolic conditions. In contrast, current evidence supports a more tailored approach for otherwise healthy individuals with normal baseline investigations, for whom less frequent laboratory monitoring appears to be both safe and cost-effective.25 Such a stratified approach to monitoring may improve patient compliance and reduce unnecessary healthcare costs without compromising safety.

In addition to systemic effects, emerging case reports have highlighted potential cardiovascular adverse events associated with isotretinoin, including PVCs and atrial tachycardia.15 These arrhythmias developed during the course of treatment and were not present prior to isotretinoin initiation. Importantly, in both cases, the symptoms resolved completely following discontinuation of the drug, suggesting a reversible and potentially drug-induced mechanism. The temporal relationship between the onset of these cardiac symptoms and isotretinoin use strengthens the hypothesis of a causal association. Although causality cannot be definitively established from isolated reports, the consistency in clinical course and resolution upon drug withdrawal indicates that isotretinoin may exert arrhythmogenic effects in susceptible individuals. These findings underscore the need for greater awareness of potential cardiac risks, especially in patients with a personal or family history of arrhythmias, and may warrant further investigation into routine cardiac screening protocols during isotretinoin therapy.15 Please refer to Fig. 2 for an algorithm of the clinical management for patients using isotretinoin at cardiovascular risk.

Figure 2.

Clinical management algorithm for isotretinoin in patients at cardiovascular risk. Ca, Calcium; ECG, Electrocardiogram; K, Potassium; LFTs, Liver function tests; Mg, Magnesium; QT, QT Interval; Zn, Zinc.

Because so few patients experience markedly aberrant reactions to isotretinoin medication, routine blood testing during treatment is not required. It has been proposed in some studies that most patients should only undergo restricted blood testing (includes hepatic function test, lipid profile and pregnancy test), whereas those who exhibit a notable change in their liver enzymes, cholesterol, or triglycerides should undergo more thorough blood testing.26 Refer to Table 4 for a detailed overview of the risk factors associated with ECG changes during isotretinoin therapy, and Table 5 for recommendations for clinical practice and monitoring.

In addition to isotretinoin, systemic antibiotics, hormone therapies, and other retinoids are commonly used to treat acne. Tetracyclines, such as doxycycline and minocycline, are the principal oral antibiotics. As stated by Dreno et al., “The preferred treatment for acne involves tetracycline antibiotics because of their potent anti-inflammatory properties, such as inhibiting neutrophil chemotaxis and lowering proinflammatory cytokine production”.2 Although commonly used, they are generally not linked to ECG irregularities.

Hormonal therapies, such as Combined Oral Contraceptives (COCs) and spironolactone, are especially effective for women with hormonal acne and can be used alongside antibiotics.2 Although these agents affect vascular tone and coagulation, they have not demonstrated reliable ECG effects in otherwise healthy people.27

Isotretinoin, on the other hand, remains the most comprehensive treatment, targeting all four basic acne processes. It is the only medication acknowledged for targeting the four pathogenic mechanisms of acne.2 In a six-month study, all patients maintained sinus rhythm with no atrial arrhythmias. Another study observed no significant difference in ECG parameters before and after therapy.28 Nonetheless, rare cardiac events, such as premature ventricular contractions, atrial tachycardia, and dilated cardiomyopathy, have been documented.29

Isotretinoin distinctly lowers sebum production and influences sebocyte activity at the molecular level, unlike other retinoids such as adapalene or tazarotene. This differentiates it from the typical class effects observed in retinoid therapy, providing a more lasting and thorough strategy for managing acne.30 Please refer to Table 6 for the comparative adverse effect profiles and cardiovascular safety of the main systemic acne treatments.

The existing research examining ECG changes in patients on isotretinoin treatment is limited by various methodological flaws. A significant amount of the accessible data comes from individual case reports and limited observational studies, which diminishes the external validity and strength of their findings. These reports frequently detail rare cardiac symptoms, like atrial tachycardia, QT interval elongation, or premature ventricular contractions, without utilizing standardized monitoring or comparison control groups.27

Furthermore, there is a substantial lack of planned clinical trials that incorporate systematic ECG measurements throughout treatment. Many current studies use before-and-after designs with small sample sizes, limiting the capacity to draw statistically meaningful conclusions about arrhythmic risk. Differences in dosage, treatment duration, and subject characteristics among trials make interpretation more difficult.31

However, future clinical trials assessing ECG abnormalities associated with oral isotretinoin should use standardized monitoring and design criteria to improve methodological rigor. Trials should include a baseline ECG and monthly ECG assessments throughout the treatment period to detect early electrophysiological changes similar to the temporal pattern seen in laboratory abnormalities such as triglyceride and transaminase elevations, which appear within the first 1‒3 months of therapy. A follow-up ECG (≥1-month after cessation) is recommended to assess reversibility. Uniform laboratory monitoring, focusing on lipids at baseline and months 1‒2, as well as hepatic and triglyceride markers at baseline, and as clinically prescribed, would be needed as a part of an efficient monitoring protocol. Importantly, the inclusion of control groups, whether placebo or active comparators (e.g., doxycycline, spironolactone, or COCs), is required for allocating observed ECG alterations to isotretinoin. Trial participants should be followed for at least 3‒6 months after therapy to detect delayed arrhythmias or conduction abnormalities. Core outcomes should include the frequency and severity of QTc prolongation, arrhythmias, and conduction anomalies, as well as any symptom-related observations. This systematic method would considerably improve the evidence base, allowing the discovery of rare or delayed occurrences, and allow for rigorous comparisons of therapies.32–34

A significant concern is the possibility of publication bias. Reports and studies detailing unusual or new cardiovascular effects are more prone to publication, while results showing no heart abnormalities might not be published. This biased reporting may result in an inflated perception of isotretinoin-related ECG irregularities in the published studies.31