Side Effects

Chloroquine and its congeners can cause two typical effects in the eye, a keratopathy and a specific retinopathy. Both of these effects are associated with the administration of the drug over longer periods of time. Chloroquine-induced keratopathy is limited to the corneal epithelium, where high concentrations of the drug are readily demonstrable. Slit lamp examination shows a series of punctate opacities scattered diffusely over the cornea; these are sometimes seen as lines just below the center of the cornea, while thicker yellow lines may be seen in the stroma.

The “gray syndrome” is the term given to the vasomotor collapse that occurs in neonates who are given excessive parenteral doses of chloramphenicol. The syndrome is characterized by an ashen gray, cyanotic color of the skin, a fall in body temperature, vomiting, a protuberant abdomen, refusal to suck, irregular and rapid respiration, and lethargy. It is mainly seen in newborn infants, particularly when premature.

Albendazole has been used in the treatment of human hookworm and trichuriasis. In a mass-treatment report from Western Australia 295 individuals in a remote rural area were treated with albendazole 400 mg/day for 5 days because of possible Giardia lamblia and hookworm infections. The 37% prevalence of Giardia fell to 12% between days 6 and 9, but rose again to 28% between days 18 and 30. The effect on hookworms (Ankylostoma duodenale) was more pronounced and more sustained with a reduction of the pretreatment prevalence of hookworm infections from 76% before treatment to 0% after 3^1 weeks.

In a double-blind, multicenter study 171 patients who had acute pyelonephritis were given intravenous cefuroxime for 2-3 days, followed by ceftibuten 200 mg bd or norfloxacin 400 mg bd for 10 days. There were fewer bacterial relapses after oral norfloxacin than ceftibuten. Adverse events were reported by 47% of the patients taking ceftibuten and by 38% of those taking norfloxacin. This difference was not significant, but diarrhea or loose stools occurred more often with ceftibuten.

Over a number of years, ivermectin has shown excellent results in the treatment of onchocerciasis, both in controlled studies and in the field, including use in the WHO-sponsored program of treatment. This experience has provided a thorough picture of its adverse effects. The effective dosage is of the order of 50-200 micrograms/kg.

Supine and postural tachycardia with postural hypotension can occur; in one large study, such effects were found in three of 40 patients. In another there was hypotension in 13 of 69 cases, but in some series these effects have not been observed at all. A massive community study in Ghana noted hypotension in only 37 of nearly 15 000 patients treated.

Emesis, ataxia, and mydriasis are cardinal signs of ivermectin toxicity. The safety, tolerability, and pharma-cokinetics of escalating high-dose ivermectin have been studied in 68 healthy subjects in a randomized, double-blind, placebo-controlled study in the following doses: Ivermectin was generally well tolerated. Quantitative pupillometry ruled out any mydriatic effect of ivermectin.

Among the published studies some have specifically sought to define the pattern of adverse effects. In one such study, although a single dose of the drug was combined in some patients with diethylcarbamazine, the adverse effect pattern was similar to that when ivermectin was used alone. There now seem to be some circumstances in which a single low dose of ivermectin is sufficient to have a prolonged effect, for example in loaiasis a dose of 150 micrograms/kg resulted in a very much reduced level of microfilaria as much as a year later, and seemed to eliminate the infestation entirely in more than half the users. If further work confirms the validity of this approach, the adverse reactions problem may be lessened, since at these doses the few reactions experienced were limited to the skin and joints, although some calabar-like swellings were also noted.

Ofloxacin ophthalmic is one of the medications to treat bacterial infections of the eye. The main active ingredient is also used in the Ofloxacin ear drops, which proved their effectiveness over time. Both remedies are to be applied with precaution and according to the prescription.

Minocycline and doxycycline are predominantly eliminated by the liver and biliary tract (70-90%). Therefore, no change in dose is needed in patients with impaired renal function. However, it should be considered that hepatic elimination of doxycycline or minocycline might be accelerated by co-administration of agents that induce hepatic enzymes.