Hi everyone, today in this video let us discuss tretinoin as topical medication. What is this drug tretinoin. Tretinoin is one of the topical medication which is used in the treatment of acne, this drug can also be used to treat the wrinkles on the face. And chemically tretinoin is a vitamin A derivative since this compound is having four double bonds all in the trans configuration, this tretinoin is one of the all trans-retinoic acid derivative. Being a retinoid, this drug can be used in the treatment of acne as well as wrinkles and it is available as a topical route. But this drug should not be given to the children with age less than 12 years because of any toxicity of retinoic acid derivatives. Generally acne is involved with cornification of epithelial cells and excessive keratinization. In such conditions, tretinoin can be used, which is available as a cream as well as a gel, this gel is available as a microsphere form which is increase the absorption into the skin. These formulations are available in different concentrations and when this tretinoin is topically applied, it can increase the detachment of cornified cells which reduce the skin eruptions that are associated with acne and it also increase the shedding of keratinocytes which further reduce the acne proliferation. And with use of tretinoin we can observe some decreased melanin pigmentation because of increased turnover of keratinocytes. Because of all these actions, tretinoin can reduce the acne formation as well as it can reduce the wrinkle formation so it can be topically used to treat these two conditions. So today in this video we are going to discuss how this drug really act at the molecular level, what is its chemical nature, what are the important precautions, side effects and dosage forms, all these things we will discuss in this video. First of all let's see how this drug acts. Within the inflammatory cells, the tretinoin can enter into the cytoplasm and it's one of the target is the DNA within the nucleus. Tretinoin is the vitamin A derivative, it is chemically a retinoid so it can bind to one of the receptor RAR retinoic acid receptor. Once it is bound to the retinoic acid receptor within the nucleus, it can activate another receptor RXR, which is the retinoid X receptor, again this receptor is activated by tretinoin. So after activation, these receptors can form a dimerization this is a heterodimer where the retinoic acid receptor forms a dimer with retinoid X receptor. This dimer can interact with the DNA at a particular region which is called RARE, retinoic acid responsive elements. So here it undergoes gene transcription and it can produce the protein synthesis and because of these actions and activation of retinoic acid receptors, it may result in the increased epidermal proliferation which reduce the cornification and acne formation. Similarly the activation of retinoid X receptors may produce cell differentiation which increases the apoptosis. Finally interaction with the DNA may increase the proteins synthesis, these proteins can release few of the mediators like TGF beta, which may induce the formation of many types of mRNA which are going to control the release of inflammatory mediators. In this way, the release of inflammatory mediators is somewhat reduced which reduce the acne proliferation and wrinkle formation. At the same time, cornified cells are detached and epidermal proliferation is increased to restore the skin structure and reduce the acne formation. By all these actions, tretinoin can be used as a topical medication for the treatment of acne and skin wrinkles. Now let us see the precautions of this drug. One of the important precautions of tretinoin is that this drug when it is applied on the skin it can produce some local skin irritation. This is very important because it can reduce the patient compliance so when this tretinoin is indicated for the treatment of acne, in the early few weeks of the treatment, the severity of the acne may be increased because of skin eruptions and detachment of cornified epithelial cells and even shedding of keratinocytes because of all these actions of tretinoin, initially the reddening of the skin may be increased, skin irritation increases and dryness of the skin can be observed which reflects like an increase in the acne formation. But these symptoms are generally associated with actions of tretinoin where it can reduce the acne proliferation when it is used for long term. But this skin irritation is one of the important precautions that should be considered in the people , when this skin irritation is not tolerated immediately the drug should be discarded, this cream should not be applied on the broken skin or inflamed skin where it can further increase the skin irritation. Similarly in the people with eczema, the skin irritation may be more pronounced so in such people tretinoin should be carefully used as it may produce some severe skin irritation, reddening and swelling of the skin. By taking proper precautions skin irritation produced by tretinoin can be reduced, generally this tretinoin should be applied on the skin which is washed properly and even after application, the skin irritation can be minimized by washing with a non-medicated soap. But at the same time, this drug can produce some skin itching so scrubbing of the skin is not recommended as it further increase the skin irritation. So if it is required the local area should be washed with a non-medicated soap and it should be dried with a clean cloth without any scrubbing action to reduce the skin irritation. And if it is required a moisturizer can be applied at the local area to minimize the irritation as well as reddening of the skin. But even with taking all precautions if anyone gets severe skin irritation with use of tretinoin, then it should be discarded as it may increase the hypersensitive reactions. Second important precaution of tretinoin is that this drug may increase the risk of phototoxicity. So when this drug is applied on the skin it can increase the sensitivity of the skin as well as it can change the pigmentation pattern so those people who are applying the tretinoin topically, if they are directly exposed to the sunlight it may increase the risk of phototoxicity so in such people the direct exposure to the sunlight should be avoided in order to eliminate severe phototoxicity. Similarly the exposure to the UV radiation can also increase the phototoxicity so caution should be taken while using the tretinoin and any exposure to the direct sunlight and UV radiation should be avoided but in few of the people those working in such environment where exposure of either sunlight or UV radiation is more possible in such conditions any sunscreen lotion should be applied with SPF value greater than 15 such that it can protect the effect of UV radiation or sunlight to avoid the phototoxicity produced by tretinoin. Similarly precautions should be taken while applying the tretinoin to the people, you should not be in contact with eye or mouth or vagina in order to reduce the skin irritation, only it should be applied on the affected area as a thin film at low dose possible in order to reduce skin irritation, skin dryness and redness of the skin. What are the side effects. The important side effects of tretinoin are mainly local reactions, when this drug is applied it can produce skin irritation, dryness of the skin, itching sensation, burning as well as stinging sensation can be observed with this tretinoin. Even it can affect the pigmentation it can either increase the pigmentation or it can reduce the pigmentation so either hyper or hypo pigmentation can be observed with use of tretinoin. And another effect is the erythema, redness of the skin can be observed, this tretinoin can also induce the nasopharyngitis and even it can increase the urticaria, all these effects can be observed because of local reactions of tretinoin. What is the chemical nature of this drug. So this is the structure of tretinoin, here you can observe four double bonds are there, all these are in the trans configuration, let us give the numbering, we have to start the numbering from carboxylic acid so this is one, two, three, four, five, six, seven, eight and nine. So now this is a nine carbon carboxylic acid derivative with four double bonds so we can write this as nona tetraenoic acid with double bonds at second, fourth, sixth and eighth position. So we can write this as nona-2,4,6,8- tetraenoic acid. To this nona tetraenoic acid, methyl groups are attached at third position and seventh position so 3,7-dimethyl, ninth position is cyclohexenyl ring is attached so 9- cyclohexen-1-yl. To this cyclohexene, again methyl groups are attached let us give the numbering to this cyclohexene, this is first one, this is second one, similarly this is the sixth one. So second position one methyl group and sixth position two methyl groups so we can write this as 2,6,6- trimethyl so this is the complete name of tretinoin. How it is given. This drug is available as a cream as well as gel, it is available at different strengths, as a cream it is available from 0.02 percent, 0.025 percent, it is available up to 0.1 percent. As a gel it is available from 0.04 percent, 0.08 percent and 0.1 percent. Either cream or gel should be applied as a thin film once daily before the bedtime in order to minimize the skin irritation and before application of this medication, the particular local area should be thoroughly washed and should be dried but it should not be scrubbed in order to avoid any unnecessary skin irritation. So that's all about this drug tretinoin, which is a topical medication indicated for the treatment of acne as well as wrinkle treatment. This drug is available as a cream as well as gel and this drug is a vitamin A derivative and it is chemically called as all trans retinoic acid derivative. When it is applied on the skin it can produce some skin irritation, dryness of the skin and redness of the skin, by taking careful precautions this skin irritation can be minimized and this drug can reduce the acne formation by increased detachment of cornified cells as well as increased shedding of the keratinocytes and it also affect the pigmentation and many of the times it can produce hyporpigmentation. So that's all about this drug tretinoin, hope you have enjoyed this video, If you like this video please subscribe to our Channel, share this video with your friends, post your comments in the comment box, thank you for watching this video.