chlorpheniramine vs terazosin
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of chlorpheniramine and terazosin. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
Terazosin has been used concomitantly in at least 50 patients on the following drugs or drug classes: analgesic/anti-inflammatory (e.g., acetaminophen, aspirin, codeine, ibuprofen, indomethacin); antibiotics (e.g., erythromycin, trimethoprim and sulfamethoxazole); anticholinergic/sympathomimetics (e.g., phenylephrine hydrochloride, phenylpropanolamine hydrochloride, pseudoephedrine hydrochloride); antigout (e.g., allopurinol); antihistamines (e.g., chlorpheniramine); cardiovascular agents (e.g., atenolol, hydrochlorothiazide, methyclothiazide, propranolol); corticosteroids;...
Chlor-Trimeton
Hytrin
Chlorpheniramine is an antihistamine medicine. It helps relieve allergy symptoms.
Terazosin is a medicine that can help men with enlarged prostate and also treat high blood pressure. It works by relaxing certain muscles in your body.
This medicine temporarily relieves symptoms from allergies or a cold. It can help with sneezing, runny nose, and itchy eyes. It also helps with itching of the nose or throat.
Terazosin is used to treat enlarged prostate in men. An enlarged prostate can cause problems with urination. Terazosin helps improve urine flow and reduce symptoms. It is also used to treat high blood pressure, either alone or with other medicines.
Chlorpheniramine blocks histamine, a natural substance your body makes during an allergic reaction. By blocking histamine, it reduces allergy symptoms. This medicine is a first-generation antihistamine.
Terazosin belongs to a class of drugs called alpha-1 blockers. It works by relaxing the muscles in the prostate and bladder neck, making it easier to urinate. It also relaxes blood vessels, which helps to lower blood pressure.
- • Dizziness
- • Constipation
- • Feeling weak or tired
- • Dizziness
- • Stuffy nose
- • Headache
- Nausea 601
- Diarrhoea 568
- Fatigue 467
- Dyspnoea 416
- Pyrexia 383
- Fatigue 466
- Diarrhoea 395
- Dizziness 385
- Dyspnoea 383
- Asthenia 351
No specific warnings noted.
Be careful when you first start taking terazosin, as it can cause your blood pressure to drop too low. This can lead to dizziness or fainting. Take your first dose at bedtime and be careful when standing up.
If you are pregnant or breastfeeding, talk to your doctor before using this medicine. They can advise you on whether it is safe for you and your baby.
It is not known if terazosin can harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if terazosin passes into breast milk, so talk to your doctor if you are breastfeeding.
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How to Read This chlorpheniramine vs terazosin Comparison
chlorpheniramine is classified in the First-Generation Antihistamine drug class, while terazosin sits within the Alpha-1 Blocker class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are split between OTC and prescription status, which affects access and supervision.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, chlorpheniramine has 2,435 submissions while terazosin has 1,980. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to these drugs can both cause sleepiness and may lower your blood pressure, making you feel more dizzy or lightheaded.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for chlorpheniramine or terazosin.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.