Topical minoxidil reduces blood pressure

A Case Report of Successful Treatment of Minoxidil Toxicosis Using Hemodialysis in a Cat

A 5-year-old castrated male American Shorthair cat presented with lethargy and anorexia after accidentally knocking over a bottle of topical minoxidil and spilling it onto its body. Physical examination revealed rapid shallow breathing, pale mucous membranes, hypothermia, tachycardia, and hypotension. Thoracic radiography revealed mild pulmonary infiltration and pleural effusion. Despite conservative treatment, including oxygen therapy, and intravenous fluid, furosemide, and dopamine administration, the patient showed no improvement. After two sessions of intermittent hemodialysis, the cat's respiratory pattern and overall condition gradually improved; normal body temperature and blood pressure were achieved. The cat recovered fully and was discharged on the 11th day of hospitalization. This is the first report on the use of hemodialysis in the treatment of a cat with minoxidil toxicosis.

Topical Minoxidil Overdose in a Young Man With Androgenetic Alopecia: A Case Report

Minoxidil is an effective and relatively safe topical drug that is used to treat androgenetic alopecia and other types of alopecia. This active ingredient is used in dermatology as a hair growth stimulant; however, the use of solutions containing minoxidil can be accompanied by a variety of cardiovascular systemic side effects. In this case report, we describe the case of a 23-year-old man who presented with complaints of dizziness, blurred vision, general malaise, fatigue, and feeling pre-syncopal while standing after applying large amounts of topical minoxidil solution for three days in a row. Other potential causes of the presenting condition were excluded. The symptoms quickly resolved after the discontinuation of minoxidil. No other treatment was used apart from minoxidil withdrawal.

Topical Minoxidil Exposures and Toxicoses in Dogs and Cats: 211 Cases (2001-2019)

Topical minoxidil is a medication for hair loss, initially available in the United States by prescription only and available since 1996 as an over-the-counter product. To determine the epidemiology of minoxidil exposures and toxicoses in dogs and cats, 211 dog and cat cases with topical minoxidil exposure were identified from the American Society for the Prevention of Cruelty to Animals Animal Poison Control Center database. In 87 cases with clinical signs of toxicosis (62 cats, 25 dogs), case narratives were reviewed and coded for exposure-related circumstances. Unintentional delivery, especially while pet owners applied minoxidil for his/her own hair loss (e.g., pet licked owner's skin or pillowcase, pet was splashed during a medication spill), was the most common cat exposure circumstance. Exploratory behavior (e.g., searching through trash) was the most common dog exposure circumstance. Clinical signs occurred in dogs and cats even with low exposure amounts, such as drops or licks. In patients that developed clinical signs, most developed moderate or major illness (56.0% dogs, 59.7% cats). Death occurred in 8/62 (12.9%) cats that developed clinical signs after the pet owner's minoxidil use. Pet owners should be educated on the risk of dog and cat toxicosis from accidental minoxidil exposure.

The hydroxypropyl-β-cyclodextrin-minoxidil inclusion complex improves the cardiovascular and proliferative adverse effects of minoxidil in male rats: Implications in the treatment of alopecia

The efficacy of minoxidil (MXD) ethanolic solutions (1%-5% w/v) in the treatment of androgenetic alopecia is limited by adverse reactions. The toxicological effects of repeated topical applications of escalating dose (0.035%-3.5% w/v) and of single and twice daily doses (3.5% w/v) of a novel hydroxypropyl-β-cyclodextrin MXD GEL formulation (MXD/HP-β-CD) and a MXD solution were investigated in male rats. The cardiovascular effects were evaluated by telemetric monitoring of ECG and arterial pressure in free-moving rats. Ultrasonographic evaluation of cardiac morphology and function, and histopathological and biochemical analysis of the tissues, were performed. A pharmacovigilance investigation was undertaken using the EudraVigilance database for the evaluation of the potential cancer-related effects of topical MXD. Following the application of repeated escalating doses of MXD solution, cardiac hypertrophy, hypotension, enhanced serum natriuretic peptides and K+ -ion levels, serum liver biomarkers, and histological lesions including renal cancer were observed. In addition, the administration of a twice daily dose of MXD solution, at SF rat vs human = 311, caused reductions in the systolic, diastolic, and mean blood pressure of the rats (-30.76 ± 3%, -28.84 ± 4%, and -30.66 ± 5%, respectively, vs the baseline; t test P < .05). These effects were not reversible following washout of the MXD solution. Retrospective investigation showed 32 cases of cancer associated with the use of topical MXD in humans. The rats treated with MXD HP-β-CD were less severely affected. MXD causes proliferative adverse effects. The MXD HP-β-CD inclusion complex reduces these adverse effects.

Topical absorption and systemic toxicity

Dermal absorption of some chemicals and drugs can cause systemic toxicity. We evaluated several case reports from the past decade, which discuss the dermal absorption of a specific chemical and potential local and systemic effects. We focused on herbicide and pesticide exposure along with exposure to cutaneous medication, occupational contact, and cosmeceutical exposure. Although causality cannot be established in most cases, it is critical to be aware of the possible effects of topical absorption that may not be immediately apparent. We recommended further studies on specific chemicals to ascertain causality and determine the highest exposure level with no observed adverse affect level (NOAEL) and the reference dose (RfD). Post-marketing epidemiology data in most geographical areas are markedly limited. A weak link in public health resides in the inadequate reporting and workup of alleged chemically related adverse effects. This arena mandates a re-thinking of how to increase this reporting, and workup, as a backup to our preclinical and clinical studies. Public awareness and funding will be rewarded by increased evidence to backup pre-approval pre-marketing studies.

Protection against cytosine arabinoside-induced alopecia by minoxidil in a rat animal model

BACKGROUND

Alopecia is one of the most physically and psychologically distressing side effect of cancer chemotherapeutic agents. In the past 2 years, we reported that: (a) treatment of 8-day-old rats with 1-B-D-arabinofuranosylcytosine (Ara-C), doxorubicin, and cyclophosphamide (CYC) consistently produced alopecia; (b) Imuvert, a biological response modifier, produced complete protection against alopecia induced by Ara-C and doxorubicin, but not that produced by CYC, most probably through the release of interleukin-1; and (c) n-acetylcysteine protected against CYC-induced alopecia in the newborn rat.

METHODS

As an extension to these observations, we chose to test the efficacy of minoxidil, a drug known to be a hypertrichotic agent, in preventing chemotherapy-induced alopecia in the newborn rat animal model.

RESULTS

Minoxidil, when injected locally, offered good local prevention against Ara-C but not CYC-induced alopecia. Minoxidil 2% dissolved in a vehicle of ethanol, propylene glycol, and water was not effective when applied topically.

CONCLUSIONS

The mechanism of action of minoxidil in its prevention against Ara-C-induced alopecia is currently unknown. This observation may shed some light on the in vivo mechanism of action of minoxidil and may prove to be important in our efforts to search for agents to prevent alopecia among patients receiving chemotherapy.

Generalized hypertrichosis after treatment with topical minoxidil

Generalized hypertrichosis is a common side-effect of oral minoxidil treatment for hypertension. However, hypertrichosis is uncommon after treatment with topical minoxidil for alopecia, and normally only occurs in areas close to the site of application. A 16-year-old girl is presented who developed generalized hypertrichosis 3 months after applying topical minoxidil for treatment of diffuse alopecia in doses greater than that prescribed. Four months after discontinuing treatment, the abnormal hair gradually diminished and disappeared.

Topical minoxidil: cardiac effects in bald man

Systemic cardiovascular effects during chronic treatment with topical minoxidil vs placebo were evaluated using a double-blind, randomized design for two parallel groups (n = 20 for minoxidil, n = 15 for placebo). During 6 months of follow-up, blood pressure did not change, whereas minoxidil increased heart rate by 3-5 beats min-1. Compared with placebo, topical minoxidil caused significant increases in LV end-diastolic volume, in cardiac output (by 0.751 min-1) and in LV mass (by 5 g m-2). We conclude that in healthy subjects short-term use of topical minoxidil is likely not to be detrimental. However, safety needs to be established regarding ischaemic symptoms in patients with coronary artery disease as well as for the possible development of LV hypertrophy in healthy subjects during years of therapy.

Topical minoxidil. A preliminary review of its pharmacodynamic properties and therapeutic efficacy in alopecia areata and alopecia androgenetica

When minoxidil is administered orally for periods in excess of 1 month, hypertrichosis occurs as a side effect in a majority of patients. Consequently, topical minoxidil has been developed to try to improve hair growth in patients with alopecia areata and alopecia androgenetica. Preliminary studies have shown that topical minoxidil promotes cosmetically acceptable hair regrowth in a variable proportion of patients with alopecia areata. Data from a large multicentre trial indicate that cosmetically worthwhile results are achieved in about one-third of subjects with alopecia androgenetica after 1 year of treatment. A much higher proportion (about 80%) of patients with alopecia androgenetica exhibited some non-vellus hair regrowth after 1 year, and whether more of these patients would develop a cosmetically acceptable result with a longer treatment period is an important area of future investigation. Initial indications suggest that less severe disease is a predictor of likely response. Thus, topical minoxidil would seem to be a useful treatment modality for patients with alopecia androgenetica--a disease for which no other safe and effective drug therapy exists. Results from treating patients with alopecia areata with topical minoxidil, although encouraging, have been more variable and require further evaluation. Even though a number of questions remain to be answered about topical minoxidil (as would be expected at this stage in its development), it would seem to be the first available drug with the potential to promote substantial hair regrowth in these divergent diseases.