Successful management of minoxidil toxicosis in a dog

CASE DESCRIPTION A 2-year-old sexually intact female mixed-breed dog was evaluated at an emergency hospital approximately 5 hours after ingestion of an unknown amount of over-the-counter topical hair growth promoter containing 5% minoxidil foam. Vomiting and signs of lethargy were reported by the owner, and physical examination revealed tachycardia and hypotension. No treatments were performed, and the dog was transferred to a veterinary referral hospital for management of suspected minoxidil toxicosis. CLINICAL FINDINGS On arrival at the referral hospital, the dog was tachycardic (heart rate, 200 to 220 beats/min) and hypotensive (systolic arterial blood pressure, 70 mm Hg). Electrocardiography revealed a regular, narrow-complex tachycardia with no evidence of ventricular ectopy. TREATMENT AND OUTCOME Hypotension was effectively managed with a constant rate infusion of dopamine hydrochloride (12.5 μg/kg/min [5.7 μg/lb/min], IV). Once normotensive, the dog remained tachycardic and a constant rate infusion of esmolol hydrochloride (40 μg/kg/min [18.2 μg/lb/min], IV) was initiated for heart rate control. A lipid emulsion was administered IV as a potential antidote for the toxic effects of the lipophilic minoxidil, with an initial bolus of 1.5 mL/kg (0.7 mL/lb) given over 15 minutes followed by a continuous rate infusion at 0.25 mL/kg/min (0.11 mL/lb/min) for 60 minutes. While hospitalized, the dog also received maropitant citrate and ondansetron. Resolution of clinical signs was achieved with treatment, and the dog was discharged from the hospital 36 hours after admission. Four days later, the owner reported that the dog had made a full recovery and had returned to its typical behavior and activity level at home. CLINICAL RELEVANCE To the authors' knowledge, this is the first report of successful clinical management of accidental minoxidil toxicosis in a dog.

Topical minoxidil: accidental poisoning in children

Hypotension and persistent tachycardia in a young girl after ingesting minoxidil cutaneous solution intended for her father.

[A case of minoxidil intoxication]

A 26-year-old man was found unable to move after oral consumption of 120 mL of RiUP X5® (containing 5 g/100 mL minoxidil) as a suicidal attempt. The patient complaining of frequent vomiting and weakness was transferred to our hospital. Findings on arrival: GCS E4V5M6; respiratory rate 24/ min; blood pressure 83/43 mmHg; pulse 152/min, regular; SpO₂97% (oxygen by mask: 6 L/min); thus, the patient was in shock. The systolic blood pressure and the pulse rate improved to about 90 mmHg and to about 130/min, respectively, in response to rapid intravenous infusion of 2,000 mL of lactated Ringer's solution. His circulatory condition tended to improve with parenteral fluid infusion alone. Forty hours after admission, however, heart failure developed due to excessive I.V. fluid infusion and abnormal body fluid distribution associated with delayed vascular smooth muscle relaxation; therefore, mechanical ventilation was initiated. Simultaneously, intravenous noradrenaline infusion was started because of a fall of the blood pressure. Subsequently, as the patient's respiratory and circulatory conditions gradually improved, he was weaned from mechanical ventilation, and the noradrenaline infusion was discontinued at 108 hours after admission. The patient made favorable progress and was discharged home on the 9th hospital day. Minoxidil exerts adverse effects mainly on the cardiovascular system. Since minoxidil is an over-the-counter drug readily available to the public, and emergency physicians should be aware of its severe toxicity.

Overdose of Rogaine Extra Strength for Men topical minoxidil preparation

CASE REPORT

Minoxidil is a potent arterial vasodilator used in the treatment of hypertension. A side effect, hypertrichosis, has prompted the marketing of a topical preparation, Rogaine, for the treatment of male-pattern baldness. Recently, a 5% solution of minoxidil became available over-the-counter as Rogaine Extra Strength For Men Hair Regrowth Treatment. We describe an oral overdose of minoxidil 3 g as the Rogaine Extra Strength preparation. Toxicity manifested as profound hypotension, requiring vasopressor support, intubation, prolonged tachycardia, and fluid overload with pleural effusions, requiring several days of therapy with furosemide. This is the largest reported ingestion of minoxidil and the first reported overdose of the extra strength 5% solution.

Minoxidil overdose

A 52-year-old man ingested 60 ml of 2 percent topical minoxidil solution resulting in severe hypotension and tachycardia. He was resuscitated with intravenously administered crystalloid solution and treated with intravenously administered dopamine, resulting in a partial hemodynamic improvement. Further treatment with intravenously administered phenylephrine infusion resulted in resolution of hypotension. The patient suffered a non-Q-wave myocardial infarction as a result of the ingestion. The toxicity of this increasingly common preparation is profound.

Minoxidil overdose with ECG changes: case report and review

A 20-year-old female ingested an unknown quantity of minoxidil tablets as a suicide gesture. She presented to the emergency department about 90 minutes later with tachycardia, diffuse T wave inversion, and S-T segment depression on the ECG, labile hypotension, and a substantially elevated total serum minoxidil concentration of 3140 ng/mL. She responded to supportive therapy with intravenous fluids, and was discharged 32 hours later with stable blood pressure and mild residual tachycardia. The clinical toxicology, treatment, and previous case reports of minoxidil overdose are reviewed.

Severe toxicity from ingestion of a topical minoxidil preparation

A 36-year-old man ingested several products, including a topical minoxidil solution. Within two hours of the ingestion the patient was difficult to arouse, tachycardic, and hypotensive with a systolic BP of 90 mmHg. Dopamine was required for two days to maintain his BP. Swan-Ganz catheter measurements demonstrated an increased cardiac output and decreased systemic vascular resistance. The estimated amount of minoxidil ingested was 1,000 mg. The patient recovered fully and was discharged nine days after the ingestion. The severity of symptoms and the prolonged duration of toxicity are disturbing because this product is becoming increasingly more popular and available.