Complications
Isotretinoin has a restricted distribution programme in the US, called iPLEDGE, to minimise fetal exposure. iPLEDGE: what is the iPLEDGE® REMS (risk evaluation and mitigation strategy)? Opens in new window
About 18% to 28% of births of babies exposed to isotretinoin in utero have fetal anomalies.[45] The rate of spontaneous abortion is 18% to 22%.[46] About 30% to 60% of babies born without malformations have intellectual impairment.[47]
Any exposure to isotretinoin in the first trimester may lead to fetal defects.[48] The risk of defect decreases to 4% within 1 month after cessation of therapy.[48]
A black box warning for acitretin states that this drug is for use only by physicians experienced with systemic retinoids and with teratogenicity knowledge.
There is a theoretical risk of birth defects up to 2 years after discontinuation of acitretin, if the patient has imbibed alcohol while on treatment, because alcohol facilitates the conversion of acitretin to etretinate, which is stored in fat.[48]
Surgery and laser therapy are still considered emerging treatments for acanthosis nigricans, although laser therapy has shown efficacy in some studies.[39] Too few cases have been studied to accurately predict long-term results.
A rare but serious complication. May occur due to metformin accumulation in patient with renal impairment. Research has found metformin therapy is associated with 4.3 cases of lactic acidosis per 100,000 patient-years.[49] While this is not significantly different from the incidence in patients with type 2 diabetes mellitus who are not taking metformin, it is recommended that metformin be avoided or used with caution in patients with renal impairment. Metformin is contraindicated when eGFR is <30 mL/minute/1.73 m². Initiating treatment with metformin is not recommended in patients with an eGFR between 30 to 45 mL/minute/1.73 m²; however, in patients already on metformin with an eGFR that falls to <45 mL/minute/1.73 m², assess the risks and benefits of continuing treatment and discontinue metformin if their eGFR falls below 30 mL/minute/1.73 m². Metformin should also be discontinued in: patients undergoing imaging with iodinated contrast medium who have an eGFR between 30 to 60 mL/minute/1.73 m²; patients with a history of liver disease, heart failure, or alcoholism; or patients who are to be given intra-arterial iodinated contrast.[50][51] Metformin is often contraindicated in patients with hepatic dysfunction, pulmonary disease, congestive heart failure, peripheral vascular disease, or those aged over 64 years; all of which may increase the risk of tissue anoxia and, theoretically, lactic acidosis.[49]
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