Drinking alcohol is generally not recommended while taking antihistamines, especially older first-generation antihistamines, because it can increase drowsiness, dizziness, and impaired coordination. Many health sources advise avoiding alcohol with any antihistamine, and some suggest waiting or discussing with a healthcare professional if there's a specific need or reaction concerns. Key points to consider:

• First-generation antihistamines (e.g., diphenhydramine/Benadryl) tend to cause more sedation; alcohol can markedly amplify these effects.
• Second-generation antihistamines (e.g., cetirizine/Zyrtec, loratadine/Claritin) are less sedating, but alcohol can still increase drowsiness or impair performance in some people.
• Individual responses vary; if already feeling sleepy from the medication, avoid alcohol entirely.
• If a medical emergency occurs (wheezing, swelling, breathing difficulty) after alcohol consumption while on an antihistamine, seek urgent care.

Practical guidance:

• Check the specific antihistamine you’re taking (brand and generation) and follow the label instructions.
• If uncertain, err on the side of caution and avoid alcohol while taking the medication.
• If you must drink, consider delaying alcohol until after the medication has fully cleared your system and you are certain you do not feel drowsy from the drug (timing will depend on the drug’s half-life; many antihistamines have active effects for 24 hours or more).

If you share the exact antihistamine you’re using (and whether it’s a first- or second-generation type), more tailored guidance can be provided.