Hydroxychloroquine (Plaquenil)
Plaquenil is used for the treatment of systemic lupus erythematosus, rheumatoid arthritis, and other inflammatory and dermatologic conditions. Retinal toxicity from Plaquenil is of serious concern because even after cessation of the drug there is little if any visual recovery, and sometimes a progression of visual loss over several years after the drug has been stopped. No medical therapy has proven effective in Plaquenil toxicity other than cessation of the drug. There may be a stage of very early functional loss where cessation of the drug will allow a reversal of the toxicity. However significant clinical recovery does not occur after bull's eye maculopathy becomes evident.
There appears to be minimal risk of toxicity for individuals using less than 6.5 mg/kg of hydroxychloroquine or 3 mg/kg of chloroquine for less than 5 years. Hydroxychloroquine has been prescribed typically at a dosage of either 200 or 400 mg/day, because of the tablet size, rather than on a per weight basis. A 200 mg daily dose will be relatively safe for all but extremely small individuals (less than 68 pounds or 31 kg, if of average build), but a daily dosage of 400 mg puts anyone under 135 pounds (62 kg) in the higher-risk category.
The baseline and subsequent eye examination includes Amsler Grid examination, Humphrey 10-2 visual field test, color vision test and color photographs of the retina. If a baseline examination is normal and dosages are at the relatively safe levels, screening during the next 5 years can be at the frequency of regular ophthalmic examinations. Annual screening during the first 5 years of usage is recommended only for individuals who are at higher risk because of their higher dosage, duration of use (more than 5 years), or other complicating factors (kidney or liver disease, obesity).
Reference: Recommendations on screening for chloroquine and hydroxychloroquine retinopathy - a report by the American Academy of Ophthalmology Ophthalmology 2002 Jul;109(7):1377-82.
Tamoxifen (Nolvadex)
Tamoxifen is a drug used in the treatment of breast cancer. Ocular side effects consist of crystalline retinopathy, corneal deposits, and optic neuritis. Ocular side effects to tamoxifen are relatively rare, with the reported incidence in the literature varying between 0.9% and 12%. There is evidence of retinal nerve fiber degeneration. Cessation of treatment usually prevents further deterioration but may not result in visual recovery.
Phenothiazines
Phenothiazines are a group of drugs used in psychiatry e.g. for treating psychotic symptoms and schizophrenia. Mellaril and Thorazine are commonly used drugs of this group.
? Thioridazine (Mellaril)
Mellaril is known to induce retinal pigment changes. Acute toxic effects of thioridazine include blurred vision, night vision problems and color vision problems and typically become evident within 2 to 8 weeks after receiving doses in excess of 800 mg/d. Early fundus examination may be normal or may show fine salt-and-pepper pigmentary retinopathy involving both the posterior pole and periphery. The precise amount of drug needed to produce pigmentary retinopathy is unclear; however, dosages up to 800 mg/d are generally considered safe. Thioridazine can remain bound to melanin in the retinal pigment epithelial cells for many years with progressive visual loss despite discontinuation of their use. Geographic retinal pigment epithelial and choriocapillaris atrophy may occur.
? Chlorpromazine (Thorazine)
Thorazine has been shown to be associated with pigmented corneal deposits and anterior capsular cataracts. Pigmentary retinopathy is usually associated with a much higher dose (>2400 mg/d). Pigment deposition on the cornea and lens appears to be dose related and is usually irreversible. Chlorpromazine-induced anterior cataracts do not normally extend to the rest of the lens even when patients continue taking chlorpromazine. They usually enjoy good vision for a long period despite a dense cataract at the pupillary region.
Sildenafil (Viagra)
Viagra is an oral medication for the treatment of male erectile dysfunction. Although the drug is marketed solely as therapy for impotence, its ability to intensify and prolong the erectile response has led to off-label and illicit use as a sexual potency drug.
Patients taking Viagra may complain of a bluish tinge or haze to vision, or a sense of increased light sensitivity. These symptoms follow the general time course of the plasma concentration of Viagra, becoming most prominent about an hour after taking the drug and disappearing over 3 to 4 hours. Vision symptoms are infrequent at the lowest clinical doses of the drug (25 and 50 mg), with a reported incidence of roughly 3%. However, the incidence of visual complaints rises to 11% after a 100-mg dose and is near 50% when patients use 200 mg dose. Patients taking up to 200-mg doses show no changes in visual acuity, contrast sensitivity, visual fields, or pupil responses. However, color vision testing shows an increase in errors at 100-mg and 200-mg doses. At these doses, the patients have increased difficulty with subtle color discriminations, particularly in the blue-green range (Surv Ophthalmol 1999;44:153-162).
Viagra and Vision Loss / Blindness
According to the FDA vision loss has been reported in 38 men taking Viagra and among four men taking Cialis (NYTimes.com May 27,2005). The vision loss occurs due to ischemic injury to the optic nerve - a condition referred to as nonarteritic anterior ischemic optic neuropathy (NAION). The onset of NAION within hours after ingestion of Viagra supports an association between use of this drug and NAION. Patients with erectile dysfunction are more likely to have the microvascular risk factors typically associated with spontaneous NAION but an ischemic effect of Viagra on the optic nerve is also plausible. The Food and Drug Administration has asked Pfizer Inc. to include a warning of possible vision loss in people taking Viagra. Until further investigations and clinical data allows for definitive conclusions, current recommendation based on weak anecdotal evidence is that patients with a history of monocular NAION be cautioned that Viagra may increase the risk of NAION in the fellow eye. (J Neuroophthalmol. 2005 Mar;25(1):9-13)
Pfizer statement regarding Viagra (May 27, 2005): "A review of 103 Viagra clinical trials involving 13,000 patients found no reports of non-arteritic anterior ischemic optic neuropathy (NAION). Outside of clinical trials, Viagra has been used by more than 23 million men worldwide over the past seven years and reports of visual field loss due to NAION are extremely rare. There is no evidence showing that NAION occurred more frequently in men taking Viagra than men of similar age and health who did not take Viagra. NAION is the most common acute optic nerve disease in adults over age 50 and it shares a number of common risk factors with erectile dysfunction: age over 50, high blood pressure, high cholesterol, diabetes. Most of the reported cases in which NAION has occurred in men taking Viagra have involved patients with underlying anatomic or vascular risk factors associated with the development of NAION."
FDA Updates Labeling for Viagra, Cialis and Levitra for Rare Post-Marketing Reports of Eye Problems (July 8, 2005): The Food and Drug Administration approved updated labeling for Cialis, Levitra and Viagra to reflect a small number of post-marketing reports of sudden vision loss, attributed to NAION (non arteritic ischemic optic neuropathy), a condition where blood flow is blocked to the optic nerve. FDA advises patients to stop taking these medicines, and call a doctor or healthcare provider right away if they experience sudden or decreased vision loss in one or both eyes. Further, patients taking or considering taking these products should inform their health care professionals if they have ever had severe loss of vision, which might reflect a prior episode of NAION. Such patients are at an increased risk of developing NAION again. At this time, it is not possible to determine whether these oral medicines for erectile dysfunction were the cause of the loss of eyesight or whether the problem is related to other factors such as high blood pressure or diabetes, or to a combination of these problems.
Plaquenil is used for the treatment of systemic lupus erythematosus, rheumatoid arthritis, and other inflammatory and dermatologic conditions. Retinal toxicity from Plaquenil is of serious concern because even after cessation of the drug there is little if any visual recovery, and sometimes a progression of visual loss over several years after the drug has been stopped. No medical therapy has proven effective in Plaquenil toxicity other than cessation of the drug. There may be a stage of very early functional loss where cessation of the drug will allow a reversal of the toxicity. However significant clinical recovery does not occur after bull's eye maculopathy becomes evident.
There appears to be minimal risk of toxicity for individuals using less than 6.5 mg/kg of hydroxychloroquine or 3 mg/kg of chloroquine for less than 5 years. Hydroxychloroquine has been prescribed typically at a dosage of either 200 or 400 mg/day, because of the tablet size, rather than on a per weight basis. A 200 mg daily dose will be relatively safe for all but extremely small individuals (less than 68 pounds or 31 kg, if of average build), but a daily dosage of 400 mg puts anyone under 135 pounds (62 kg) in the higher-risk category.
The baseline and subsequent eye examination includes Amsler Grid examination, Humphrey 10-2 visual field test, color vision test and color photographs of the retina. If a baseline examination is normal and dosages are at the relatively safe levels, screening during the next 5 years can be at the frequency of regular ophthalmic examinations. Annual screening during the first 5 years of usage is recommended only for individuals who are at higher risk because of their higher dosage, duration of use (more than 5 years), or other complicating factors (kidney or liver disease, obesity).
Reference: Recommendations on screening for chloroquine and hydroxychloroquine retinopathy - a report by the American Academy of Ophthalmology Ophthalmology 2002 Jul;109(7):1377-82.
Tamoxifen (Nolvadex)
Tamoxifen is a drug used in the treatment of breast cancer. Ocular side effects consist of crystalline retinopathy, corneal deposits, and optic neuritis. Ocular side effects to tamoxifen are relatively rare, with the reported incidence in the literature varying between 0.9% and 12%. There is evidence of retinal nerve fiber degeneration. Cessation of treatment usually prevents further deterioration but may not result in visual recovery.
Phenothiazines
Phenothiazines are a group of drugs used in psychiatry e.g. for treating psychotic symptoms and schizophrenia. Mellaril and Thorazine are commonly used drugs of this group.
? Thioridazine (Mellaril)
Mellaril is known to induce retinal pigment changes. Acute toxic effects of thioridazine include blurred vision, night vision problems and color vision problems and typically become evident within 2 to 8 weeks after receiving doses in excess of 800 mg/d. Early fundus examination may be normal or may show fine salt-and-pepper pigmentary retinopathy involving both the posterior pole and periphery. The precise amount of drug needed to produce pigmentary retinopathy is unclear; however, dosages up to 800 mg/d are generally considered safe. Thioridazine can remain bound to melanin in the retinal pigment epithelial cells for many years with progressive visual loss despite discontinuation of their use. Geographic retinal pigment epithelial and choriocapillaris atrophy may occur.
? Chlorpromazine (Thorazine)
Thorazine has been shown to be associated with pigmented corneal deposits and anterior capsular cataracts. Pigmentary retinopathy is usually associated with a much higher dose (>2400 mg/d). Pigment deposition on the cornea and lens appears to be dose related and is usually irreversible. Chlorpromazine-induced anterior cataracts do not normally extend to the rest of the lens even when patients continue taking chlorpromazine. They usually enjoy good vision for a long period despite a dense cataract at the pupillary region.
Sildenafil (Viagra)
Viagra is an oral medication for the treatment of male erectile dysfunction. Although the drug is marketed solely as therapy for impotence, its ability to intensify and prolong the erectile response has led to off-label and illicit use as a sexual potency drug.
Patients taking Viagra may complain of a bluish tinge or haze to vision, or a sense of increased light sensitivity. These symptoms follow the general time course of the plasma concentration of Viagra, becoming most prominent about an hour after taking the drug and disappearing over 3 to 4 hours. Vision symptoms are infrequent at the lowest clinical doses of the drug (25 and 50 mg), with a reported incidence of roughly 3%. However, the incidence of visual complaints rises to 11% after a 100-mg dose and is near 50% when patients use 200 mg dose. Patients taking up to 200-mg doses show no changes in visual acuity, contrast sensitivity, visual fields, or pupil responses. However, color vision testing shows an increase in errors at 100-mg and 200-mg doses. At these doses, the patients have increased difficulty with subtle color discriminations, particularly in the blue-green range (Surv Ophthalmol 1999;44:153-162).
Viagra and Vision Loss / Blindness
According to the FDA vision loss has been reported in 38 men taking Viagra and among four men taking Cialis (NYTimes.com May 27,2005). The vision loss occurs due to ischemic injury to the optic nerve - a condition referred to as nonarteritic anterior ischemic optic neuropathy (NAION). The onset of NAION within hours after ingestion of Viagra supports an association between use of this drug and NAION. Patients with erectile dysfunction are more likely to have the microvascular risk factors typically associated with spontaneous NAION but an ischemic effect of Viagra on the optic nerve is also plausible. The Food and Drug Administration has asked Pfizer Inc. to include a warning of possible vision loss in people taking Viagra. Until further investigations and clinical data allows for definitive conclusions, current recommendation based on weak anecdotal evidence is that patients with a history of monocular NAION be cautioned that Viagra may increase the risk of NAION in the fellow eye. (J Neuroophthalmol. 2005 Mar;25(1):9-13)
Pfizer statement regarding Viagra (May 27, 2005): "A review of 103 Viagra clinical trials involving 13,000 patients found no reports of non-arteritic anterior ischemic optic neuropathy (NAION). Outside of clinical trials, Viagra has been used by more than 23 million men worldwide over the past seven years and reports of visual field loss due to NAION are extremely rare. There is no evidence showing that NAION occurred more frequently in men taking Viagra than men of similar age and health who did not take Viagra. NAION is the most common acute optic nerve disease in adults over age 50 and it shares a number of common risk factors with erectile dysfunction: age over 50, high blood pressure, high cholesterol, diabetes. Most of the reported cases in which NAION has occurred in men taking Viagra have involved patients with underlying anatomic or vascular risk factors associated with the development of NAION."
FDA Updates Labeling for Viagra, Cialis and Levitra for Rare Post-Marketing Reports of Eye Problems (July 8, 2005): The Food and Drug Administration approved updated labeling for Cialis, Levitra and Viagra to reflect a small number of post-marketing reports of sudden vision loss, attributed to NAION (non arteritic ischemic optic neuropathy), a condition where blood flow is blocked to the optic nerve. FDA advises patients to stop taking these medicines, and call a doctor or healthcare provider right away if they experience sudden or decreased vision loss in one or both eyes. Further, patients taking or considering taking these products should inform their health care professionals if they have ever had severe loss of vision, which might reflect a prior episode of NAION. Such patients are at an increased risk of developing NAION again. At this time, it is not possible to determine whether these oral medicines for erectile dysfunction were the cause of the loss of eyesight or whether the problem is related to other factors such as high blood pressure or diabetes, or to a combination of these problems.
No comments:
Post a Comment