Propylthiouracil in psoriasis: results of an open trial

Therapies with Antioxidant Potential in Psoriasis, Vitiligo, and Lichen Planus

Oxidative stress plays an important pathogenetic role in many chronic inflammatory diseases, including those of dermatological interest. In particular, regarding psoriasis, vitiligo, and lichen planus, excess reactive oxygen species and a decline in endogenous antioxidant systems are observed. In this regard, treatments with antioxidant properties could be appropriate therapeutic options. To date, clinical trials in dermatology on these treatments are limited. We reviewed the available studies on the efficacy of antioxidant therapies in psoriasis, vitiligo, and lichen planus. The role of herbal derivatives, vitamins, and trace elements was analyzed. The antioxidant properties of conventional therapies were also evaluated. Data from the literature suggest that antioxidants might be useful, but available studies on this topic are limited, heterogeneous, not completely standardized, and on small populations. Furthermore, in most cases, antioxidants alone are unable to induce significant clinical changes, except perhaps in mild forms, and must be used in conjunction with standard drug treatments to achieve measurable results. Further studies need to be conducted, considering larger populations and using internationally validated scales, in order to compare the results and clinical efficacy.

The association of thyroid dysfunction with chronic plaque psoriasis: A hospital-based retrospective descriptive observational study

Background:

Associations among thyroid dysfunction, thyroid autoimmunity, and clinical features including age, gender, disease duration, and severity of psoriasis is less studied.

Objectives:

To study frequency of thyroid dysfunction and thyroid autoimmunity and examine association among thyroid dysfunction, thyroid autoimmunity, and clinical features including gender, age, duration, and severity of psoriasis.

Material and Methods:

The medical records of 290 (m:f 2.15:1) patients aged 13–75 years with plaque psoriasis were analyzed for thyroid dysfunction and thyroid autoimmunity. Thyroid dysfunction was defined as 10% variation in any thyroid hormone levels. Thyroid autoimmunity was diagnosed from presence of antithyroid peroxide (anti-TPO) antibodies.

Results:

The majority, 57.9% patients, was aged ≥41 years (Type-2 psoriasis) and duration of disease was <5 years in 58.6% patients. Mild and moderate to severe psoriasis was present in 58.3% and 41.7% patients, respectively. Deranged thyroid functions were present in 29 (10%) patients. Hypothyroidism and hyperthyroidism occurred in 5.4% and 2.7% patients, respectively. Anti-TPO antibodies were observed in 13.5% patients; 11had hypothyroidism. There was no statistically significant difference in gender, age, duration, and severity of psoriasis when compared with patients having normal thyroid function tests.

Conclusion:

The study suggests possible thyroid dysregulation and thyroid autoimmunity in psoriasis but results need careful interpretation and clinical application. Their significance as standalone risk factor for the chronicity, severity, and relapses in psoriasis or whether thyroid hormone replacement or antithyroid drugs become a useful therapeutic option remains tenuous at best for need of more robust evidence. Retrospective, observational, cross-sectional study design, small number of patients, and lack of controls remain major limitations.

Oxidative stress in psoriasis and potential therapeutic use of antioxidants

The pathophysiology of psoriasis is complex and dynamic. Recently, the involvement of oxidative stress in the pathogenesis of psoriasis has been proposed. Oxidative stress is an imbalance between oxidants and antioxidants in favor of the oxidants, leading to a disruption of redox signaling and control and/or molecular damage. In this article, the published studies on the role of oxidative stress in psoriasis pathogenesis are reviewed, focusing on the impacts of oxidative stress on dendritic cells, T lymphocytes, and keratinocytes, on angiogenesis and on inflammatory signaling (mitogen-activated protein kinase, nuclear factor-κB, and Janus kinase/signal transducer and activator of transcription). As there is compelling evidence that oxidative stress is involved in the pathogenesis of psoriasis, the possibility of using this information to develop novel strategies for treatment of patients with psoriasis is of considerable interest. In this article, we also review the published studies on treating psoriasis with antioxidants and drugs with antioxidant activity.

Clinical Usefulness of a Long-Term Treatment with an Antithyroid Drug for Psoriasis Vulgaris

We have previously reported that an antithyroid thiourethylene, thiamazole, can bring about significant clinical improvement in patients with psoriasis vulgaris. Although the efficacy of antithyroid thiourethylenes had been reported earlier, few studies have evaluated the safety of its long-term use. In this study, we aimed to study whether or not long-term thiamazole administration is complicated by any adverse effects. Eight patients with psoriasis vulgaris were enrolled in this study after informed consent was obtained. Each patient was administered thiamazole orally at 30 mg/day for 12 weeks. Two patients achieved complete clearance of psoriatic lesions. Four patients showed a significant improvement, and two patients did not reach satisfactory improvement. Some adverse effects developed in five patients; serum TSH levels elevated above the normal range in three patients and fell below the normal range in one patient. However, serum free-T3 and free-T4 levels remained within normal ranges during the treatment in all patients, and none of the patients developed clinical hypothyroidism. This preliminary study suggests that thiamazole administration is an effective and relatively safe treatment for patients with psoriasis vulgaris.

Acrodermatitis continua of Hallopeau: evolution of treatment options

Ever since its inception, acrodermatitis continua of Hallopeau, has been recognized as an uncommon clinical entity which has been sparingly reported from across the globe. The attempt to have cumulative information on prevalent nomenclature, definition, reminiscences, and clinical overtures has brought differential diagnosis and diagnosis in sharp focus, the highlights of which are outlined. Hence, it was considered important to review the evolution of treatment options available thus far including use of biologics.

Oral propylthiouracil for the treatment of resistant plaque psoriasis

BACKGROUND

Propylthiouracil (PTU) has been used in the treatment of hyperthyroidism for many years and inhibits the enzyme 5'-deiodinase, which converts thyroxine to triiodothyronine. Several studies have reported PTU as an effective treatment for plaque psoriasis. PTU exhibits immunomodulatory effects; however, its exact mechanism of action in psoriasis is unknown. Few patients were studied in these reports and treatment with PTU was continued for no longer than 8 weeks.

METHODS

In this study we report on four patients with resistant plaque psoriasis who had treatment with oral PTU for 4-32 weeks (mean 18.4).

RESULTS

Three of the four patients exhibited moderate clinical improvement with reductions in psoriasis severity observed within 4-6 weeks of commencing PTU therapy. The side effects noted were subclinical hypothyroidism in two patients and worsening of muscle aches in one patient. Monitoring included regular thyroid function, full blood count, and liver and renal function tests.

CONCLUSION

This study illustrates that oral PTU can be a useful addition to the therapy of resistant cases of plaque psoriasis and shows that this treatment can be continued for longer than 8 weeks with few side effects occurring secondary to PTU.

Preparation and Characterization of Propylthiouracil Niosomes

Propylthiouracil, a lyophobic drug with an antiproliferative activity, was formulated into niosomes using various classes of nonionic surfactants. Feasibility of vesicle formation by the sonication method was evaluated. Size and size distribution was measured by laser diffraction. Entrapment and drug release over 24 h were monitored by UV spectrophotometric method at 275 nm. The results revealed that niosomes readily formed from various compositions of nonionic surfactant and cholesterol, with or without a stabilizer. Entrapment of PTU in niosomes depended on bilayer composition. The release of PTU from all niosomal formulations studied was retarded and followed the first-order kinetics. Degree of slow release had a negative correlation with drug entrapment. The release rate also depended on the physical state of the bilayer. The results of this study indicate that PTU niosomes were able to control the release of PTU and might be of value to develop further into topical formulations.

Palmar skin lesions reversed by propylthiouracil therapy

Antithyroid thioureylene compounds such as propylthiouracil, methimazole, and thiamazole have been shown to have some beneficial effect in the treatment of plaque psoriasis in small clinical trials. An incidental finding is reported here on a patient with autoimmune polyendocrine syndrome type II who had dermatitis-like palmar skin lesions on the right palm, which was reversed with propylthiouracil therapy.

p16 expression in psoriatic lesions following therapy with propylthiouracil, an antithyroid thioureylene

Plaque formation is a characteristic finding in patients with psoriasis and reflects cytokine-induced keratinocyte proliferation and/or impaired apoptosis of keratinocytes. Antithyroid thioureylenes such as propylthiouracil (PTU) and methimazole (MMI) are effective in the treatment of plaque psoriasis. Following PTU and MMI treatment, proliferative cell nuclear antigen (PCNA) expression is significantly reduced, suggesting that these medications have an antiproliferative effect. p16 is an antiapoptotic protein that is present in relative abundance in psoriatic plaques and is believed to play a potential role in the persistent senescence and impaired apoptosis of the keratinocytes in the plaque. This study examined p16 expression in biopsy samples of eight patients with plaque psoriasis given 300 mg of propylthiouracil in divided doses for 3 months. Despite significant clinical and histological improvement with PTU treatment, p16 expression was essentially unchanged, suggesting that the beneficial effect of PTU in psoriasis is not mediated through a decrease in p16 expression. The effect of PTU on other antiapoptotic proteins such as bcl-xL remains to be determined.

Serum TNF-alpha in psoriasis after treatment with propylthiouracil, an antithyroid thioureylene

Background

Tumor necrosis factor-α (TNF-α) and its receptors play important roles in the development and persistence of psoriatic plaques. The antithyroid thioureylenes, propylthiouracil and methimazole, are effective in the treatment of patients with psoriasis with a significant number of patients showing clearing or near clearing of their lesions after a several weeks of treatment.

Methods

The present study examined the effect of treatment with propylthiouracil, given in a dose of 100 mg every 8 hours for 3 months, on the serum levels of TNF-α in 9 patients with plaque psoriasis.

Results

Propylthiouracil therapy did not result in a significant decline in serum TNF-α concentrations.

Conclusions

The findings suggest that the therapeutic effect of propylthiouracil in psoriasis appears not to be related to any change in the concentration of TNF-α but occurs via an anti-proliferative mechanism as we have previously speculated.

Anti-thyroid thioureylenes in the treatment of psoriasis

Psoriasis is a common skin disorder associated with significant morbidity. Many agents are used in the medical management of this debilitating condition with the newer anti-cytokine agents being the most recent addition to the pharmacological armamentarium to battle the disorder. Cost concerns are very important with the newer "biologic" treatments costing in excess of 10,000 US dollars annually. The need for cheaper, orally administered agents is therefore imperative. This paper addresses the potential role of anti-thyroid thioureylenes, propylthiouracil and methimazole, in the treatment of psoriasis and reviews the possible mechanism of action of these drugs in this disorder. It is hypothesized that the beneficial effect of anti-thyroid thioureylenes in psoriasis is linked to their effect as anti-proliferative agents as reflected by significant decrease in markers of cellular proliferation such as proliferative cell nuclear antigen in biopsy specimens after treatment with these drugs. Propylthiouracil has been shown to bind to the hepatic T 3 receptor and it is possible that propylthiouracil (6-n-propyl-2-thiouracil) binding to the ligand-binding site normally occupied by T 3 impairs transcription by inactivating the effect of T 3 as well as by squelching retinoic X receptor heterodimer formation with other receptors of the steroid receptor superfamily such as the peroxisome proliferator-activated receptor, retinoic acid receptor and vitamin D receptors.

CD1a expression in psoriatic skin following treatment with propylthiouracil, an antithyroid thioureylene

BACKGROUND

The antithyroid thioureylenes, propylthiouracil (PTU) and methimazole (MMI), are effective in the treatment of patients with plaque psoriasis. The mechanism of action of the drugs in psoriasis is unknown. Since the drugs reduce circulating IL-12 levels in patients with Graves' hyperthyroidism, the effect of propylthiouracil on CD1a expression in psoriatic lesions was examined in biopsy samples of patients with plaque psoriasis. CD1a is a marker of differentiated skin antigen presenting cells (APC, Langerhans cells). Langerhans cells and skin monocyte/macrophages are the source of IL-12, a key cytokine involved in the events that lead to formation of the psoriatic plaque.

METHODS

Biopsy specimens were obtained from six patients with plaque psoriasis who were treated with 300 mg propylthiouracil (PTU) daily for three months. Clinical response to PTU as assessed by PASI scores, histological changes after treatment, and CD1a expression in lesional skin before and after treatment were studied.

RESULTS

Despite significant improvement in clinical and histological parameters the expression of CD1a staining cells in the epidermis did not decline with propylthiouracil treatment.

CONCLUSIONS

It appears that the beneficial effect of propylthiouracil in psoriasis is mediated by mechanisms other than by depletion of skin antigen-presenting cells.

Short-term resolution of psoriasis after total thyroidectomy for euthyroid multinodular goitre

A 36-year-old Chinese female with an 8-year history of chronic, generalized plaque psoriasis demonstrated a marked improvement of the disease after removal of an intercurrent euthyroid multinodular goitre. Thyroxine was commenced immediately postoperatively. No thyroid antibodies were detected and thyroid function and calcium levels remained within normal limits both pre- and postoperatively. Four weeks following surgery, narrow-band ultraviolet B (nbUVB) therapy was recommenced for recurrent psoriasis. The manifestations of psoriasis at this stage were less severe than before thyroidectomy and responded well to treatment, whereas before surgery the response to therapy had been poor. One year following total thyroidectomy, the patient received very effective psoriasis control with nbUVB therapy. The possible role of surgery and thyroid hormones in altering the pathogenesis of psoriasis in the acute setting is clearly of interest and warrants further research consideration.

Antioxidant potential of propylthiouracil in patients with psoriasis

OBJECTIVE

There is growing evidence supporting the reactive oxygen species (ROS) in the pathogenesis of psoriasis. Propylthiouracil(PTU), an antithyroid drug, has been shown to have beneficial effects on psoriasis. The aim of this study was to investigate both disturbances in oxidant/antioxidant system in psoriasis and whether PTU, shown to have immunomodulatory effects and antioxidant potential, has effects on oxidant/antioxidant system and clinical improvement in psoriatics.

DESIGN AND METHODS

Malondialdehyde (MDA), end product of lipid peroxidation, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and antioxidant enzymes were measured in plasma, erythrocytes and skin biopsies of psoriatics who were resistant to conventional therapy before and after 8 weeks of oral treatment with PTU (300 mg/day) or PTU/thyroxine (25 microg/day- to prevent possible hypothyroidism). The same parameters were also studied in healthy controls. Psoriasis Area and Severity Index (PASI) scores were used to evaluate the severity of the disease, and routine analyses and thyroid function tests were measured during the study.

RESULTS

Increased baseline MDA in all samples were found to be lower. In addition baseline SOD and GSH-Px in skin and erythrocytes were also lower. The increased plasma SOD levels in skin and erythrocytes of the study groups was found to be higher and lower,respectively in all patients after the treatment. No tissue parameters or erythrocyte GSH-Px were different from control levels at the end of the study. Significant clinical improvement and decreased PASI scores were observed in all patients. Post treatment TSH levels were higher in all patients, but these levels were within the reference range and none had clinical hypothyroidism.

CONCLUSION

These findings may provide some evidence for a potential role of increased lipid peroxidation and decreased antioxidant activity in psoriasis. PTU may be considered as treatment model in psoriasis, in particular for resistant cases, because of its antioxidant potential, and also antiproliferative and immunomodulatory effects.

Treatment of acrodermatitis continua of Hallopeau with oral propylthiouracil and methotrexate

A 71-year-old man with acrodermatitis continua of Hallopeau was treated successfully with a combination of oral propylthiouracil and methotrexate. After 14 weeks, he developed acute pancytopenia, an uncommon idiosyncratic side-effect of propylthiouracil, and presented with a life-threatening methicillin-resistant Staphylococcus aureus pneumonia. This illustrates the potential value and associated risks of propylthiouracil in the management of this difficult condition.

Development and validation of a high-performance liquid chromatographic method for the analysis of propylthiouracil in pharmaceuticals

A simple, rapid, and stability-indicating high-performance liquid chromatographic (HPLC) method was developed and validated for the assay of propylthiouracil (PTU). The method was used to quantify PTU in topical formulations and in tablets. Excellent linearity was observed between PTU concentration and the peak area (R2= 0.999). The limit of detection was 1 ng, and the limit of quantitation was 1.2 ng. The method proved to be selective. Selectivity was validated by subjecting a stock solution of PTU to acidic, basic, and oxidative degradations. The peaks of the degradation products did not interfere with the peak of PTU. Excipients present in the dosage forms did not interfere with the analysis, and the recovery of PTU from each dosage form was quantitative.

Effect of propylthiouracil on adenosine deaminase activity and thyroid function in patients with psoriasis

BACKGROUND

T-cell activation has been implicated in the pathogenesis of psoriasis; adenosine deaminase (ADA) activity has been considered as a marker of T-cell activation. The antithyroid drug propylthiouracil (PTU) has recently been shown to have beneficial effects on psoriatic lesions, probably by acting on the immune system.

OBJECTIVES

To investigate whether ADA activity may be related to psoriasis and whether oral PTU affects ADA activity and gives clinical improvement in psoriatic patients.

METHODS

ADA activities were measured in plasma, erythrocyte and tissue samples of patients with psoriasis before and after 2 months of treatment with either PTU 100 mg three times daily or PTU plus thyroxine 25 microg once daily (to prevent possible hypothyroidism, which may be induced by PTU) as well as in healthy controls. The severity of the disease was evaluated before and after treatment according to Psoriasis Area and Severity Index (PASI) scores. Routine analyses and thyroid function tests were also carried out during the study.

RESULTS

All patients showed significant clinical improvement in their lesions and decreased PASI scores after the treatments. Elevated baseline ADA activities in skin and plasma were found to be lower, and decreased baseline erythrocyte ADA was higher, after the treatments in all patients, and they were not different from control values. Although thyroid function tests were not affected by the treatments, serum thyroid-stimulating hormone levels were found to be higher after the treatments, and there was a larger increase in patients treated with PTU alone. However, none of the patients had clinical hypothyroidism or cytopenia.

CONCLUSIONS

ADA activity may be clinically useful for indicating T-cell activation in psoriasis. Because of its antiproliferative and immunomodulatory effects, antioxidant potential and low toxicity, PTU may be an effective agent in the treatment of psoriasis.

Recent advances in the treatment of psoriasis

We have seen great progress in the past decade in our understanding of the pathogenesis of psoriasis. The fruits of this knowledge are being realized in many of the exciting immunologic therapies currently in development. The potential for astute clinical observation to produce effective therapies and to change the direction of research has been proven in the past and still remains as an avenue for the future. Although individual treatments were discussed in this article, combination therapy is likely to continue to play a major role. Additionally, because future therapeutic developments are not likely to be free of toxicity, rotational therapy may still be necessary. Many questions remain unanswered. Substantial progress is just beginning into the.

Effect of orally administered antithyroid thioureylenes on PCNA and P53 expression in psoriatic lesions

BACKGROUND

Antithyroid thioureylenes are effective agents in the oral and topical treatment of patients with chronic plaque psoriasis.

METHOD

The effect of oral treatment with 6-n-propyl 2-thiouracil (propylthiouracil, PTU) and 2-mercapto 1-methyl imidazole (methimazole, MMI) on proliferating cell nuclear antigen (PCNA), and p53 protein expression was studied in patients with stable plaque psoriasis.

RESULTS

Following treatment with PTU and MMI, PCNA staining in psoriatic epidermis was significantly decreased. P53 was minimally expressed in untreated lesions, and treatment with PTU and MMI did not enhance p53 expression in the psoriatic lesions.

CONCLUSIONS

Since PCNA is a marker of cellular proliferation and p53 inhibits cellular cycling, some of the beneficial effects of PTU and MMI in psoriasis may depend on the ability of the drugs to impair cellular turnover, perhaps by binding to the triiodothyronine (T3) receptor. These effects may be in addition to the previously described effects of PTU and MMI as immune modulators and free radical scavengers.

Dermatologic therapy: 1993

This article reviews some therapeutic results reported in the English-language literature during 1993. Readers should review the original article in full before attempting any experimental or controversial therapy.

A controlled trial of topical propylthiouracil in the treatment of patients with psoriasis

BACKGROUND

Propylthiouracil (PTU, 6-n-propyl 2-thiouracil) is an antithyroid thioureylene, which, in addition to its ability to decrease thyroid hormone synthesis, also has immune modulatory and free radical scavenging abilities. We have previously shown that oral PTU and another antithyroid thioureylene are effective in the treatment of plaque psoriasis.

OBJECTIVE

The current study was performed to determine the efficacy of topical PTU in psoriasis.

METHODS

Topical PTU and placebo were administered, in a double-blind fashion, three times daily for 4 to 8 weeks to nine volunteers with long-standing plaque psoriasis. The patients had biopsy specimens of their lesions taken at the start and end of the study. Clinical response was monitored with a scoring system based on scale, erythema, and thickness of the plaques. Complete blood cell count and thyroid function studies were obtained in each patient at the beginning and at 2-week intervals thereafter until completion of the study.

RESULTS

Topically applied PTU produced significant clearing of the lesions (clinical scores 8.0 +/- 0.6 vs 3.7 +/- 0.3, p < 0.0001 at 4 weeks, and 4.0 +/- 0.6, p < 0.02 at 8 weeks); two patients demonstrated nearly complete clearing. Placebo-treated and untreated "control" areas showed no significant change during the study. None of the subjects had hypothyroidism or cytopenia.

CONCLUSION

Topical applied PTU is effective in the treatment of patients with stable plaque psoriasis and has low toxicity.