1.Why do I need combination therapy? For patients with moderate to severe psoriasis, it may be difficult to achieve and maintain remission of the lesions. When treating psoriasis, there is a need for both drugs that work quickly and drugs that are maintained for a long time. However, among the various treatments currently in use, the efficacy of a single one is often less than satisfactory or the efficacy is inversely proportional to the safety. In order to improve the efficacy and reduce adverse reactions, combined therapy is often needed to treat moderate to severe psoriasis. 2.How does psoriasis belong to moderate to severe condition? Currently, it is mostly classified according to the National Psoriasis Foundation. Mild: 2% of the lesion area is involved, moderate: 2% to 10% of the lesion area is involved. Severe: 10% of the lesion area is involved. The degree of disability caused by the lesions should also be taken into account when typing, for example, psoriasis occurring on the hands and feet is classified as severe despite the small extent of involvement. For example, psoriasis that occurs on the hands and feet is classified as severe even though the area of involvement is small. Therefore, lesions with an area of involvement greater than 2% of the body surface area belong to moderate to severe. 3.What are the drugs and therapies commonly used in the treatment of psoriasis? At present, the first line of drugs and methods for the treatment of psoriasis include Avelox, methotrexate, narrow-spectrum medium-wave ultraviolet light (NB-UVB) and cyclosporine A. The second line of drugs: hydroxyurea, etc. The main topical drugs commonly used are tacalcitol, carbotriol, tazarotene, glucocorticoids, tacrolimus, pimecrolimus, etc . New biological agents have also been added to the combined treatment of psoriasis this year. 4.What are the commonly used combination therapies? Conventional combination therapy: two or more drugs (or methods) are applied simultaneously with synergistic or complementary effects, and each drug is applied at a minimum dose to reduce toxicity. Specific methods include: phototherapy plus internal medication, phototherapy plus external medication, internal medication plus internal medication, external medication plus external medication, internal medication plus external medication. 5.The effect of the combination of narrow spectrum medium wave ultraviolet light (NB-UVB) and methotrexate or topical drugs? The combination of NB-UVB and methotrexate has a synergistic effect and can reduce the dosage of each, thus reducing the cumulative amount. NB-UVB can also be combined with topical drugs. Studies have confirmed that the combination of NB-UVB with tacalcitol and carbotriol is more effective. The combination of NB-UVB and tazarotene can increase the efficacy of each, but topical tazarotene can cause thinning of the epidermal layer 3 times a week for 2 weeks, so the dosage of NB-UVB should be reduced by at least 1/3. No advantage, it can not reduce the amount of NB-UVB, but can make the remission period shorten. 6.What should I pay attention to when combining systemic drugs? Aveline and methotrexate, Aveline and cyclosporine A, methotrexate and cyclosporine A, Aveline and hydroxyurea, and Aveline and methotrexate can be used in combination. Both Aveline and methotrexate can cause damage to the liver. The combination of Aveline and methotrexate should be considered only when the effect of Aveline and methotrexate alone is unsatisfactory. Liver enzymes, white blood cells and platelets must be tested regularly when combined. Alternating therapy with adequate doses of cyclosporine A and methotrexate (several months of each drug) is another combination that avoids nephrotoxicity, hypertension, and hepatotoxicity, and because both drugs have a short half-life, they can be switched to one drug after a week of discontinuation. Although alternating therapy is more expensive than methotrexate alone, the time required to treat psoriasis with methotrexate alone is increased by a factor of 1. The combination of Avia and hydroxyurea is suitable for patients with severe and stubborn psoriasis who are not suitable for methotrexate or cyclosporine A and whose disease cannot be completely controlled with Avia. 7.What is the effect of the combination of systemic and local medication? The combination of Avelox and carbotriol can reduce the dose of Avelox and increase the efficacy. The combination of Avelox and glucocorticoids is effective, and the lesions can be maintained in long-term remission with maintenance therapy after remission. The combination of cyclosporine A and caspofriol may improve the remission rate. The combination of Avia plus dithranol can improve the local penetration of dithranol and is effective for patients who were previously ineffective with dithranol treatment alone. 8.What are other effective combination therapies? The combination of tazarotene and glucocorticoids can increase the efficacy and avoid the occurrence of vincristine dermatitis, and can lead to a longer remission period. The combination of carbofurantrin and glucocorticoids can reduce the risk of skin irritation, increase the efficacy and make the effect faster than either drug alone. The combination of cyclosporine A and dithranol has been reported to be more effective than cyclosporine A alone. The combination of cyclosporine A and mycophenolate has been reported to be more effective than cyclosporine A alone. When cyclosporine A is used to treat psoriasis from efficacy to withdrawal, mycophenolate can be added to prevent rebound when the amount of cyclosporine A decreases. The combination of cyclosporine A and hydroxyurea is effective in the short course of treatment of psoriasis with small doses of cyclosporine A and hydroxyurea. Because hydroxyurea is excreted through the kidney, so long-term application should pay attention to kidney damage, and the combination also has the possibility of causing bone marrow toxicity. 9.Can it be used in combination with biological agents? At present, the commonly used biologic agents are: infliximab, etanercept, alfacalcid, efalizumab, etc., which do not produce the specific organ toxicity of other immunosuppressive agents in long-term application. Because they are not hepatotoxic and myelotoxic, they can be combined with methotrexate, and because they are not nephrotoxic, they can be safely combined with cyclosporine A. Aveloxan has no immunosuppressive effect and can be combined with biological agents. 10.What combination therapies are prohibited and have restrictions on their use? Some combination therapies are prohibited due to safety concerns. The combination of cyclosporine A and phototherapy is prohibited because cyclosporine A has immunomodulatory effects and the combination may increase the incidence of UVB and PUVA induced skin malignancies. In fact, the incidence of squamous cell carcinoma is increased in patients treated with the combination of cyclosporine and PUVA. Some patients have been successfully treated with cyclosporine A and then converted to PUVA therapy, so alternating (not applying simultaneously) is not a contraindication. Combined application of coal tar and PUVA is prohibited because it can induce significant phototoxicity. Hydroxyurea and methotrexate or azathioprine, all three of which can suppress bone marrow, should be avoided. The vast majority of the four main treatments recommended for psoriasis, namely Avelox, phototherapy, methotrexate and cyclosporine A, have significant synergistic effects when applied in combination . The combination of these treatments with topical agents such as retinoids, glucocorticoids, vitamin D3 derivatives, and dithranol can also increase the efficacy and generally have a better safety profile. Other immune agents such as hydroxyurea, mycophenolate, and 6-thioguanine have also shown efficacy in combination therapy . Some new biological agents have been initially shown to be important adjuvant methods in combination therapy.