Rex Side Effects

Rex is an antihistamine commonly used to treat allergies and allergic reactions. Rex can have various side effects, some of which are more common than others. It’s important to note that not everyone experiences these side effects, and their severity can vary from person to person health conditions. Some common and less common side effects of Rex may include:

Common Side Effects

• Drowsiness or fatigue: Although Rex is considered a non-sedating antihistamine, some individuals might still experience mild drowsiness, especially when first starting the medication.
• Dry mouth: A common side effect of Rex is a sensation of dryness in the mouth.
• Headache: Some people may experience mild headaches while taking Rex.
• Dizziness: Feeling lightheaded or dizzy might occur, particularly at the onset of treatment or in sensitive individuals.
• Sore throat or nasal irritation: In a few cases, Rex might cause a dry or irritated throat.
• Gastrointestinal symptoms: This might include nausea, vomiting, diarrhea, or abdominal pain in some individuals.
• Increased appetite: A small number of people might experience an increase in appetite while taking Rex.
• Weight gain: Rarely, Rex might contribute to slight weight gain in some individuals.
• Muscle pain: Some individuals might experience mild muscle pain or weakness.

Less Common Side Effects

• Heart palpitations: Rarely, Rex might cause irregular or rapid heartbeat in some individuals.
• Urinary retention: Difficulty or discomfort in passing urine might occur in rare cases.
• Liver problems: There have been reports of elevated liver enzymes or liver damage associated with Rex, though this is exceedingly rare.
• Allergic reactions: While Rex is used to treat allergic reactions, in rare instances, it might cause allergic responses like rash, itching, swelling (especially of the face, lips, or tongue), severe dizziness, or trouble breathing.
• Mood changes or confusion: Some individuals might experience changes in mood, irritability, or confusion.
• Visual disturbances: Blurred vision or other visual disturbances are possible, although infrequent.
• Joint pain: Rarely, Rex might cause joint pain or discomfort.
• Tremors or shaking: Some individuals might experience tremors or shaking, particularly in the hands.
• Insomnia or sleep disturbances: While Rex is considered non-sedating for most people, it can cause sleep disturbances such as difficulty falling asleep in a small percentage of users.
• Hypersensitivity reactions: In very rare cases, Rex might cause severe allergic reactions known as hypersensitivity syndrome, which includes symptoms such as fever, rash, swollen lymph nodes, and organ inflammation.

Rex is one of the leading brands of Cetirizine Dihydrochloride, manufactured and marketed by Albro Pharma (Pakistan).

Presently, Rex is available in Tablet and Syrup Forms with the following strengths.

Rex Tablet : 10mg strength.

Rex Syrup : 5mg/5ml strength.

1. Central Nervous System (CNS) Depressants: Combining Rex with other medications that have a sedative effect, such as benzodiazepines, certain antipsychotics, muscle relaxants, or opioids, can potentiate drowsiness. Although Rex is considered non-sedating, the additive effect can still cause increased drowsiness or impaired alertness.
2. Alcohol: Drinking alcohol while taking Rex can increase drowsiness and impair your ability to perform tasks requiring mental alertness.
3. Antihistamines: Combining Rex with other antihistamines, whether prescription or over-the-counter, can intensify the antihistaminic effects and may increase the risk of side effects.
4. CYP3A4 Inhibitors: Medications that inhibit the CYP3A4 enzyme, such as ketoconazole, erythromycin, or ritonavir, might increase the blood levels of Rex, potentially leading to enhanced effects or a higher risk of side effects.
5. Kidney Function: Drugs that affect kidney function or are excreted through the kidneys might potentially interact with Rex. Although Rex is mainly excreted unchanged in the urine, drugs that affect kidney function might alter its elimination.
6. Other Medications: While Rex is generally considered safe to use with most medications, it’s always wise to consult with a healthcare professional before combining it with other prescription or over-the-counter medications, including herbal supplements and vitamins.