Retigel20 gm

Retigel is a synthetic oral retinoid used mainly in dermatology. Its uses can be classified by strength of evidence as follows:

Established / approved indication

• Severe, recalcitrant nodular acne in patients who have not responded adequately to conventional therapy, including courses of systemic antibiotics combined with topical treatment. Retigel is reserved for this severe, scarring form of acne because of its serious risk profile.

Guideline-supported / commonly used off-label indications

• Severe inflammatory acne variants such as acne conglobata and acne fulminans (often used together with corticosteroids in acne fulminans).
• Gram-negative folliculitis that has failed other treatments.
• Moderate, scarring, or psychologically distressing acne that has failed standard combination therapy, sometimes using lower or intermittent-dose regimens of Retigel.
• Severe, refractory rosacea, typically at lower doses than those used for acne (off-label).

Retigel is not a first-line or routine treatment for mild-to-moderate acne; it should only be prescribed by, or under the supervision of, a physician experienced in its use.

Each soft gelatin capsule of Isotretinoin contains Isotretinoin as the active ingredient, commonly available in strengths of 10 mg, 20 mg, and 40 mg (exact strengths marketed vary by manufacturer). Capsules typically contain oily excipients (such as soybean oil, hydrogenated vegetable oil, and beeswax) to aid absorption of this lipophilic drug; some formulations use parabens as preservatives.

Retigel is a synthetic retinoid, chemically related to vitamin A (retinol), that is taken by mouth to treat severe acne. Unlike topical retinoids, Retigel acts systemically to shrink the sebaceous (oil-producing) glands, reduce sebum output, normalize skin cell turnover inside hair follicles, and reduce inflammation, and it is the only medication capable of producing long-term or permanent remission of severe acne after a single course. Because it is a potent teratogen with other serious potential effects, its use is tightly restricted and requires specialist supervision.

Retinoid (vitamin A derivative) — systemic anti-acne agent.

Isotretinoin is a retinoid that binds intracellular retinoic acid receptors, altering gene transcription in sebaceous glands and follicular keratinocytes. This leads to marked shrinkage of sebaceous glands, reduced sebum production (by up to 90%), normalized follicular keratinization (reducing comedone formation), and secondary reduction of Cutibacterium acnes colonization and inflammation.

Pharmacokinetics

• Absorption: Bioavailability is variable and significantly increased (roughly doubled) when Isotretinoin is taken with a fatty meal.
• Distribution: Highly protein bound (>99.9%, mainly to albumin); highly lipophilic.
• Metabolism: Extensively metabolized in the liver (largely via CYP2C8 and other CYP enzymes) to its major active metabolite, 4-oxo-isotretinoin, and to tretinoin.
• Elimination: Terminal half-life of the parent drug is approximately 19 hours (longer for the 4-oxo metabolite); eliminated roughly equally in urine and feces as metabolites.

Retigel capsules should be swallowed whole with a full glass of water, taken with food (a fatty meal improves absorption); do not chew or crush the capsule. Take it at approximately the same time(s) each day. Do not take any additional vitamin A supplements while on Retigel (see Interactions). Before starting therapy in a person who can become pregnant, mandatory pregnancy testing and use of effective contraception are required as described in the Pregnancy section — treatment should only begin once these requirements are met.

Clinically significant interactions with Retigel include:

• Tetracycline antibiotics (e.g. tetracycline, doxycycline, minocycline): concomitant use is contraindicated because of an increased risk of pseudotumor cerebri (idiopathic intracranial hypertension), which can cause permanent vision loss.
• Vitamin A supplements: concomitant use is contraindicated as it adds to the toxicity (including hypervitaminosis A features) of Retigel.
• Progestin-only ("mini-pill") oral contraceptives: reliability may be reduced; a combined hormonal method or non-hormonal barrier method is preferred for pregnancy prevention during Retigel therapy.
• Systemic corticosteroids: concurrent long-term use may add to the risk of bone density loss associated with Retigel.
• Phenytoin: may add to the risk of bone loss (osteoporosis) seen with Retigel.
• Other photosensitizing drugs and alcohol: may add to photosensitivity and, with alcohol, to the risk of elevated triglycerides/liver effects associated with Retigel; minimize sun exposure and limit alcohol during treatment.

Side effects of Retigel are dose-related and very common; most are manageable.

Very common (expected in most patients)

• Dry skin, lips (cheilitis), and nasal mucosa (nosebleeds)
• Dry, irritated eyes; reduced tolerance to contact lenses
• Increased sensitivity to sunlight (photosensitivity)
• Mild, reversible increases in blood triglycerides, cholesterol, and liver enzymes
• Muscle and joint aches, headache

Serious (uncommon but important — seek medical attention)

• Pseudotumor cerebri (severe headache, visual disturbance, nausea/vomiting)
• Pancreatitis, especially with markedly elevated triglycerides
• Inflammatory bowel disease (persistent abdominal pain, diarrhea, rectal bleeding)
• Depression, mood changes, or suicidal thoughts (see Precautions)
• Severe allergic reactions or severe skin reactions (e.g. Stevens-Johnson syndrome) — rare
• Impaired night vision, hearing changes
• Skeletal effects (bone density loss with long-term/repeated use; premature growth-plate closure has been reported in adolescents)

Retigel carries a boxed warning for severe teratogenicity and is absolutely contraindicated in pregnancy. Even a single dose taken during pregnancy can cause major birth defects (of the brain, face, heart, and other organs), miscarriage, or premature birth. Patients who can become pregnant must have two negative pregnancy tests before starting Retigel and must use two effective, reliable forms of contraception (or commit to complete abstinence) simultaneously for one month before starting, throughout treatment, and for one month after stopping Retigel, with monthly pregnancy testing during this period. If pregnancy occurs during treatment, Retigel must be stopped immediately and the physician contacted urgently.

It is not known with certainty whether Retigel passes into breast milk, but because of its potential toxicity, breastfeeding is not recommended during treatment with Retigel; discuss feeding options with your physician.

Retigel carries boxed warnings and requires specialist supervision:

• Psychiatric effects: depression, mood changes, anxiety, aggressive behavior, and rare suicidal ideation/attempts have been reported; monitor for mood changes and seek prompt medical advice if they occur, even without a prior psychiatric history.
• Inflammatory bowel disease: discontinue immediately if severe abdominal pain, rectal bleeding, or severe diarrhea develop.
• Lipid and liver monitoring: baseline and periodic monitoring of fasting lipids and liver function tests is required; discontinue or reduce dose for marked abnormalities.
• Pseudotumor cerebri: discontinue immediately if severe headache, nausea/vomiting, or visual disturbance occur.
• Skin and eyes: expect dry skin, lips, and eyes; use moisturizers, lip balm, and lubricating eye drops; avoid waxing, dermabrasion, and laser skin treatments during and for several months after treatment (risk of scarring).
• Photosensitivity: use sun protection and avoid excessive sun/UV exposure.
• Night vision: some patients experience decreased night vision, sometimes abruptly; use caution driving or operating machinery at night.
• Blood donation: patients must not donate blood during treatment with Retigel and for one month after stopping, due to the risk of exposing a pregnant transfusion recipient.
• Pregnancy is an absolute contraindication (see Contraindications and Pregnancy and Lactation).

Overdose of Retigel may cause symptoms of acute vitamin A toxicity such as severe headache, dizziness, vomiting, dry/cracked lips, and abdominal pain. There is no specific antidote. If an overdose of Retigel is suspected, seek immediate medical attention or contact a poison control center; do not attempt home treatment.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Renal impairment: use with caution, starting at the lower end of the dosing range, as data are limited.

Hepatic impairment: use with caution and close monitoring of liver function; avoid in significant hepatic impairment (see Dosage and Administration).

Elderly: acne is uncommon in this age group; no specific dose adjustment is established, but monitor for the same adverse effects as in younger adults.

Females of reproductive potential: mandatory pregnancy testing and contraception requirements apply (see Pregnancy and Lactation).

See Pediatric Uses for use in children and adolescents.

A single course of Retigel for nodular acne is typically continued for approximately 15–20 weeks (about 4–5 months), aiming for a cumulative dose of roughly 120–150 mg/kg, which is associated with the most durable remission. Most patients achieve prolonged clearance after one course. A second course may be considered if acne relapses significantly, but only after a drug-free interval of at least 8 weeks, since further improvement may still occur after stopping.

Retinoids (vitamin A derivatives)

Isotretinoin works by binding to retinoic acid receptors inside skin cells, which changes gene expression to shrink sebaceous glands and cut sebum production, normalize the shedding of cells lining hair follicles (preventing pore blockage), and reduce inflammation and bacterial colonization associated with acne — together producing sustained remission of severe acne.

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The safety and efficacy of Retigel have not been established in children under 12 years of age, and it is not recommended for prepubertal patients. In adolescents 12 years of age and older with severe recalcitrant nodular acne who have reached puberty, Retigel is dosed on the same weight-based (mg/kg/day) schedule as adults, under close specialist supervision. Adolescents should be monitored for the same risks as adults, with particular attention to psychiatric symptoms, growth, and bone health, since rare reports of premature growth-plate closure exist with long-term or high-dose use. Pregnancy-prevention requirements apply fully to adolescents who can become pregnant.