While Valcyte exerts effective antiviral effects, it also presents significant toxic and side effects.

I. Common Side Effects of Valcyte

1. Hematological Toxicity

(1) It is one of the most severe adverse reactions of Valcyte.

(2) It may cause severe leukopenia, neutropenia, anemia, thrombocytopenia, and even aplastic anemia.

(3) Hematological toxicity can occur at any stage of treatment, and recovery generally begins 3 to 7 days after drug discontinuation.

2. Gastrointestinal Reactions

(1) Diarrhea is the most prevalent gastrointestinal side effect.

(2) Other manifestations include nausea, vomiting and abdominal pain.

(3) The incidence of diarrhea is relatively higher in renal transplant recipients.

(4) Most of these reactions are mild to moderate, but may compromise medication adherence.

3. Renal Impairment

(1) Acute renal failure may occur in elderly patients, individuals receiving concurrent nephrotoxic drugs, or dehydrated patients.

(2) Renal function requires close monitoring during medication, and dosage shall be adjusted according to creatinine clearance rate.

4. Neurological Symptoms

(1) Headache, insomnia, peripheral neuropathy, paresthesia and tremor have all been reported.

(2) Some patients may experience epilepsy, dizziness or confusion, which impairs the ability to drive and operate machinery.

5. Other Common Adverse Reactions

(1) Fever, fatigue, retinal detachment, urinary tract infection and other conditions are also common.

(2) The incidence of upper respiratory tract infection, nasopharyngitis and elevated blood creatinine in pediatric patients is higher than that in adults.

II. Measures to Alleviate Valcyte Side Effects

1. Management of Hematological Toxicity

(1) Complete blood cell count and platelet count shall be monitored frequently throughout treatment. Discontinuation should be considered if the absolute neutrophil count drops below 500/μL, platelets below 25,000/μL, or hemoglobin below 8 g/dL.

(2) Blood cell counts usually start to recover within 3 to 7 days after drug withdrawal.

(3) Hematopoietic growth factors (e.g., G-CSF) may be administered for severe cytopenia.

2. Relief of Gastrointestinal Reactions

(1) Administration with meals can enhance drug absorption and relieve gastric discomfort such as nausea.

(2) Patients with diarrhea should replenish water and electrolytes adequately to prevent dehydration.

(3) In case of severe symptoms, consult a physician for antidiarrheal medication or dosage adjustment if necessary.

3. Prevention and Management of Nephrotoxicity

(1) Serum creatinine and creatinine clearance rate should be monitored before and during treatment.

(2) Maintain adequate hydration and avoid concomitant use of other nephrotoxic agents (e.g., cyclosporine, amphotericin B, tacrolimus).

(3) Dosage adjustment based on creatinine clearance rate is required for patients with renal insufficiency.

(4) Special caution is warranted in elderly patients.

4. Intervention for Neurological Symptoms

(1) Patients with epilepsy, dizziness or confusion must refrain from driving or operating mechanical equipment.

(2) Seek prompt medical evaluation if symptoms persist or worsen; discontinue the drug or adjust the treatment regimen when needed.

5. General Supportive Measures

(1) All patients require regular follow-up with monitoring of blood routine, renal function and hepatic function.

(2) Do not self-manage any severe adverse reactions; contact a healthcare provider immediately.

(3) Physicians may prescribe dose reduction, temporary suspension or permanent discontinuation according to clinical conditions.

III. Storage Conditions of Valcyte

1. Storage of Tablets

(1) Valcyte tablets should be stored at room temperature of 20°C to 25°C, with permissible short-term fluctuations between 15°C and 30°C.

(2) Keep in the original bottle, protected from moisture and direct sunlight.

(3) Each bottle contains 60 tablets; the shelf life is subject to package labeling.

2. Storage of Oral Solution

(1) The dry powder can be stored at room temperature before reconstitution.

(2) Reconstituted oral solution must be refrigerated at 2°C to 8°C (36°F to 46°F) and used within 49 days.

(3) Freezing is strictly prohibited.

(4) Pharmacists shall mark the discard date on the bottle.