Rebound hypertension following prolonged oxymetazoline use: a signal-generating case report

Abstract

Topical nasal decongestants containing α-adrenergic agonists such as oxymetazoline are widely available over the counter and are generally perceived as safe when used as directed. Manufacturer instructions typically recommend limited dosing frequency and short-term use (e.g. up to twice daily for no more than 3–7 days, depending on product labelling). This report describes a signal-generating case of clinically significant but reversible hypertension temporally associated with prolonged use of oxymetazoline nasal spray in a previously normotensive adult. After 16 consecutive days of exposure exceeding the manufacturer-recommended duration and frequency stated on the product packaging, the patient developed diastolic-predominant hypertension peaking at 160/110 mmHg, accompanied by headache and autonomic symptoms. Serial fasting-morning home blood pressure measurements obtained using a validated automated upper-arm device documented the onset, peak and progressive normalization of blood pressure following discontinuation of oxymetazoline without initiating antihypertensive therapy, consistent with a positive dechallenge. The temporal relationship between exposure and blood pressure elevation, together with the plausible pharmacological mechanism involving systemic α-adrenergic vasoconstriction, supports classification as a probable adverse drug reaction. Prolonged oxymetazoline nasal spray use may represent an under-recognized safety risk and a potential confounder in the evaluation of new-onset hypertension. Clinicians should routinely inquire about over-the-counter medication use and duration when assessing unexplained blood pressure elevations.

Plain language summary

High blood pressure after prolonged use of an over-the-counter nasal spray: a safety case report

Oxymetazoline nasal spray is an over-the-counter medicine commonly used for short-term relief of nasal congestion. Because it is widely available without a prescription, many patients assume it is completely safe. This case report describes a patient who developed significant but reversible high blood pressure after using oxymetazoline for longer than recommended. Blood pressure returned to normal after stopping the spray without requiring long-term medication. This case highlights two important clinical lessons. First, prolonged use of oxymetazoline nasal spray may cause systemic effects, including elevated blood pressure. Second, over-the-counter medicines and the duration of their use should be carefully reviewed when evaluating unexplained hypertension in both clinical practice and home blood pressure monitoring settings. Increased awareness among healthcare professionals, trainees, and patients may help prevent unnecessary investigations and treatments.

Introduction

Topical nasal decongestants containing α-adrenergic agonists, such as oxymetazoline, are widely available over the counter (OTC) and commonly perceived as benign.^1–3 Their recommended duration of use is deliberately limited, primarily to avoid rebound nasal congestion; however, systemic adrenergic effects, including blood pressure elevation, may also occur.^4–6 Hypertension associated with topical decongestant use remains under-recognized in routine clinical practice, particularly when exposure is prolonged beyond labelling recommendations. This report describes a signal-generating case of reversible, clinically significant hypertension temporally associated with prolonged oxymetazoline use, highlighting a potential patient-safety risk relevant to pharmacovigilance. Beyond posing a safety risk, prolonged topical adrenergic agonist exposure may act as an under-recognized confounder during evaluation of elevated blood pressure in both home-monitoring and clinical settings. Chronic nasal conditions, including rhinosinusitis, are highly prevalent and associated with a substantial burden on quality of life and healthcare utilization. ⁷

Methods

The reporting of this case conforms to the CARE (CAse REport) reporting guideline. ⁸ (see Supplementary Material). Clinical information was derived from patient-reported history and structured home blood pressure monitoring records.

Case presentation

A 62-year-old man (height 176 cm, weight 92 kg; BMI 29.7) with no history of hypertension, diabetes or cardiovascular disease developed new-onset blood pressure elevation following extended use of oxymetazoline nasal spray. Throughout adult life, his baseline blood pressure ranged between 110–125 mmHg and 70–85 mmHg, with occasional low-normal values. His medical history was notable for episodic rhinosinusitis treated intermittently with OTC decongestants. Family history included paternal myocardial infarction in the context of type 2 diabetes.

The patient initiated oxymetazoline 0.05% nasal spray on 22 October 2025 for acute nasal congestion. During the first 10 days, dosing averaged three sprays per nostril daily, followed by one spray in the morning and evening for an additional 6 days, for a total exposure of 16 consecutive days. This exceeded the manufacturer-recommended duration stated on the product packaging. Recommendations beyond the specific product labelling are addressed in the ‘Discussion’ section.^1,2 No concomitant vasoactive medications were used, apart from low-dose aspirin (75 mg three times weekly); the indication was not documented.

While still using oxymetazoline, the patient reported blurred vision and lacrimation (frequency and duration were not systematically recorded). After discontinuation, he reported progressively worsening headache and neck pressure (the frequency and duration were not systematically recorded). On Day 3 post-discontinuation, morning fasting blood pressure was 120/83 mmHg (heart rate 86/min). On Day 4, blood pressure rose sharply to 150/100 mmHg in the morning, with a peak evening value of 160/110 mmHg (heart rate 73/min). No antihypertensive therapy was initiated, reflecting a conservative clinical decision to observe given the suspected medication-related aetiology. Serial morning fasting home blood pressure measurements (validated automated upper-arm device; recorded electronically and transferred to the author) obtained over Days 3–9 demonstrated progressive improvement, with values returning towards baseline by Day 9 (Figure 1). Heart rate (HR) remained within the normal range throughout. Exact daily blood pressure and heart rate values are provided in Table 1.

Figure 1.

Morning fasting systolic and diastolic blood pressure and heart rate (HR) values recorded on Days 3–9 following discontinuation of oxymetazoline nasal spray. Measurements demonstrate progressive normalization of blood pressure without antihypertensive therapy, consistent with a positive dechallenge.

Table 1.

Morning fasting, sitting blood pressure, and heart rate measurements obtained on Days 3–9 after discontinuation of oxymetazoline.

Post-withdrawal day	Date	Condition	Systolic (mmHg)	Diastolic (mmHg)	Heart rate (bpm)	Notes
Day 1	7 Nov 2025	Morning, fasting, sitting	–	–	–	No measurement; patient asymptomatic except mild evening blurred vision, lacrimation and mild headache
Day 2	8 Nov 2025	Morning, fasting, sitting	–	–	–	No measurement; mild headache intensified in the evening/night
Day 3	9 Nov 2025	Morning, fasting, sitting	120	83	86	First documented post-withdrawal BP
Day 4	10 Nov 2025	Morning, fasting, sitting	150	100	79	Hypertensive rebound evident. Evening peak 160/110 (HR 73)
Day 5	11 Nov 2025	Morning, fasting, sitting	139	97	71	Improvement begins
Day 6	12 Nov 2025	Morning, fasting, sitting	137	94	68	Gradual decrease
Day 7	13 Nov 2025	Morning, fasting, sitting	136	94	80	Stabilization phase
Day 8	14 Nov 2025	Morning, fasting, sitting	125	84	77	Significant improvement
Day 9	15 Nov 2025	Morning, fasting, sitting	120	81	62	Return to baseline

No morning fasting blood pressure or heart rate measurements were recorded on Days 1–2 post-discontinuation because symptoms were mild and non-specific, except for a headache that intensified on the evening of Day 2.

No alternative secondary cause of hypertension was identified, and symptoms resolved completely with conservative management alone in a patient with normal renal function parameters. Laboratory values from prior years showed stable renal function with creatinine, urea and electrolytes within normal range. The patient’s most recent ECG and echocardiogram (2024) were normal, as was a carotid Doppler assessment. No acute medical evaluation was required (the patient did not report an emergency department visit or in-person consultation during the episode), and symptoms resolved fully with conservative management.

Discussion

This case represents a plausible pharmacovigilance signal of rebound hypertension following prolonged exposure to oxymetazoline, an imidazoline-derived α-adrenergic agonist widely used as an over-the-counter nasal decongestant. Although topical administration is intended to limit systemic exposure, several pharmacokinetic and pharmacodynamic factors can facilitate clinically meaningful absorption, particularly when dosing exceeds recommended durations or when the nasal mucosa is inflamed.^4,5

Oxymetazoline exerts its primary therapeutic effect through α1-adrenergic receptor-mediated vasoconstriction of the nasal mucosa, with partial α2-agonist activity.^9,10 When absorbed systemically, α1-mediated vasoconstriction increases total peripheral resistance, a mechanism that preferentially elevates diastolic blood pressure. The blood pressure pattern observed in this patient, a marked diastolic elevation with preserved heart rate, aligns with this mechanism and argues against alternative explanations such as anxiety-driven sympathetic activation or emerging essential hypertension.^4–6 Although BMI approached the overweight/obesity threshold, the patient had long-standing normotensive measurements prior to exposure, reducing the likelihood of emerging essential hypertension as the primary explanation.

Manufacturer labelling for oxymetazoline products typically recommends short-term use, often limited to approximately 3–7 days depending on regional product information. Some sources or product information may mention slightly longer durations (e.g. up to 10 days); however, prolonged or repeated use beyond recommended labelling increases the risk of rebound phenomena and systemic adrenergic effects. In the present case, exposure exceeded the duration specified on the specific product packaging, highlighting the importance of adherence to labelled instructions and awareness of variability in real-world use. Several features strengthen the causal relationship between oxymetazoline exposure and the hypertensive episode. First, the temporal association was clear: blood pressure elevation occurred after prolonged exposure and peaked within 48–96 h following discontinuation, a timeframe consistent with delayed normalization of adrenergic receptor sensitivity. Second, the absence of β-adrenergic stimulation was reflected by a stable heart rate throughout the episode, suggesting intact baroreflex buffering rather than systemic catecholamine excess. Third, progressive normalization of blood pressure without antihypertensive therapy constitutes a robust positive dechallenge, a key element in pharmacovigilance causality assessment.^11,12 According to the WHO-UMC causality assessment criteria, these features support classification as a probable adverse drug reaction.^11,12

Rebound phenomena associated with topical nasal decongestants are well described at the level of the nasal mucosa, commonly manifesting as rhinitis medicamentosa. However, systemic rebound effects, including transient hypertension, are less frequently reported and may therefore be under-recognized. Given the widespread availability of oxymetazoline and similar agents, even infrequent systemic adverse effects may translate into a meaningful population-level burden.

Patient behaviour plays an important role in this context. Over-the-counter availability, rapid symptomatic relief and limited awareness of duration warnings contribute to extended or repetitive use.^13–15 In this case, the patient exceeded recommended treatment duration in the absence of medical supervision, a pattern consistent with previously reported misuse behaviours. This highlights a gap between product labelling and real-world use that is highly relevant from a drug-safety perspective.

Structured home blood pressure monitoring was instrumental in this case. Serial morning fasting measurements allowed objective documentation of onset, peak and resolution of hypertension, supporting causal inference and preventing premature initiation of long-term antihypertensive therapy.^16–18 From a pharmacovigilance standpoint, patient-generated longitudinal data can provide valuable insights into adverse drug reactions that might otherwise escape detection in routine clinical encounters.

Although this report describes a single patient, it is not intended to estimate incidence or risk magnitude. Rather, it serves as a hypothesis-generating observation that underscores the need for clinician awareness and continued surveillance of systemic effects associated with topical α-adrenergic agents. Future observational studies or aggregated case series may help clarify susceptibility factors, including age, dosing patterns, mucosal integrity and individual variability in systemic absorption.

Patient perspective

The patient reported concern regarding unexpected blood pressure elevations but felt relieved when blood pressure values normalized after discontinuation of oxymetazoline without the need for long-term antihypertensive therapy.

Conclusion

This signal-generating case suggests that prolonged use of oxymetazoline nasal spray may precipitate clinically meaningful, reversible hypertension in previously normotensive individuals. Given the widespread availability of topical nasal decongestants, clinicians should routinely inquire about OTC medication use and duration when evaluating new-onset hypertension. Increased awareness of this potential adverse effect may prevent unnecessary diagnostic work-up and treatment, and support continued pharmacovigilance attention to systemic effects of topical α-adrenergic agents.

Supplemental Material

sj-docx-1-taw-10.1177_20420986261435799 – Supplemental material for Rebound hypertension following prolonged oxymetazoline use: a signal-generating case report

Supplemental material, sj-docx-1-taw-10.1177_20420986261435799 for Rebound hypertension following prolonged oxymetazoline use: a signal-generating case report by Domenico Merante in Therapeutic Advances in Drug Safety