<p>Valsartan is generally well tolerated and side effects are rare. The most common side effects include headache, dizziness, fatigue, abdominal pain, cough, diarrhea and nausea. Patient may also experience hyperkalemia, impotency, reduced renal function, allergic reactions, dyspnea, constipation, back pain, muscle cramps, rash, anxiety, insomnia and vertigo. Hypotension may also occur if patient have been taking diuretics along with Valsartan.</p>